Use of NHS England Outcomes Data for Covid-19 purposes – HOSTED Project

Data is to be shared for the purpose of supporting a Department of Health and Social Care (DHSC) - UK Health Security Agency (UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

DATA CONTROLLER AND DATA PROCESSOR ROLES

The Controller, for UK GDPR purposes, is the Department of Health and Social Care (DHSC); the legal signatory for this agreement (and for the overarching DSFC) is the Secretary of State for Health and Social Care (acting as part of the Crown), acting through the UK Health Security Agency (hereinafter referred to as UKHSA) within the Department of Health and Social Care; and the licensee is UKHSA, not the wider DHSC.

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care (DHSC). The Agency is the national expert agency responsible with protecting the nation’s health and is responsible for preventing, detecting, analysing, responding to, and leading partnerships to protect the UK from communicable diseases and other threats to public health and acts as the Executive agency for DHSC and as such has operational autonomy from DHSC to fulfil its remit.

The Controller in the application will be shown as the DHSC with the DHSC data sharing framework contract and the DHSC security listed under Security Assurance. The Processor will be shown as UKHSA with the UKHSA DSPT listed under Security Assurance.

UKHSA is an executive agency of DHSC and as such the same legal entity, therefore there are no data processing agreements between DHSC and UKHSA.

The government’s Living with COVID strategy (https://www.gov.uk/government/publications/covid-19-response-living-with-covid-19) remains extant, placing a significant emphasis on the ability to monitor both disease activity and ensuring the vaccination programme provides sufficient protection for the population.

Covid-19 laboratory and case data from UKHSA can be linked to NHS England controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts. HOSTED remains UKHSA’s preferred national dataset to monitor these on a household basis.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of index cases and household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 index cases and household contacts

d) risk factors for Covid-19 among index cases and household contacts

e) deaths from Covid-19 among index cases and household contacts

f) vaccination status of cases of index Covid-19 infection and their household contacts **Added under version 4 of this agreement**

The analysis is for Secondary Use Purposes – the data released for HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Covid-19 remains a potential risk for morbidty and mortality, and the national vaccination programme still operates at this time, so the study requires a further year of dtaa to understand the epidemiology.

Linkage and analysis by NHS England to produce the HOSTED dataset and to support UKHSA to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government.

5. research and planning in relation to Covid-19 including assessing the national COVID-19 vaccination programmes.

The following NHS England data will be accessed:

- COVID-19 Ethnic Category Data Set

- COVID-19 General Practice Extraction Service (GPES) Data for Pandemic Planning and Research (GDPPR)

- COVID-19 Hospitalization in England Surveillance System

- COVID-19 SGSS First Positives (Second Generation Surveillance System)

- COVID-19 UK Non-hospital Antigen Testing Results (Pillar 2)

- COVID-19 Vaccination Status

- Hospital Episode Statistics Accident and Emergency (HES A and E)

- Hospital Episode Statistics Admitted Patient Care (HES APC)

- Hospital Episode Statistics Outpatients (HES OP)

- Personal Demographic Service

- Secondary Uses Service Payment By Results Episodes

Data extracts will be provided on a weekly basis.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

Where individuals have opted out of disease registration by the National Disease Registration Service (NDRS), their data has been permanently removed from the registry and therefore will not be disseminated under this Data Sharing Agreement (DSA). https://digital.nhs.uk/ndrs/patients/opting-out

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS England has agreed to share the data identified with UKHSA (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission surveillance and modelling during the course of the pandemic while SARS-CoV-2 is detected in the population.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts of deaths from Covid-19 among household contacts (including vaccination information).

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by UKHSA for clinical management or intervention at a specific household level.

The Disclosed Data will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared with the UKHSA Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by UKHSA for the purposes of providing routine and bespoke aggregate level small number suppressed reports as per the Hospital Episode Statistics (HES) analysis guide. These are:

- Routine reports to be produced for inclusion in UKHSA epidemiological reporting. These are shared with UKHSA and Department of Health and Social Care (DHSC) colleagues. In addition, results of specific focussed analyses in aggregate format with small numbers supressed are shared with technical experts as relevant, such as in relation to vaccine effectiveness. These reviews by technical experts support dissemination of the scientific findings similar to peer-review publications. In the pandemic situation, it is important to ensure relevant findings are available to experts who may be involved in discussions about interventions such as vaccinations. When these findings are shared, it is only at the level of detail of what would be described in a scientific journal article.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS England and Office for National Statistics guidance. NHS England should be quoted as the source of the Disclosed Data together with other sources.

UKHSA are not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, UKHSA will re-direct them to NHS England who will consider their request.

Changes under version 1 of this agreement in March 2021:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHS England already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHS England in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields for each vaccine dose to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (Index of Multiple Deprivation (IMD)), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts who are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant (differing) vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to UKHSA.

Changes under version 2 of this agreement in May 2021:

1. Enhanced Ethnicity Data

UKHSA have requested that the existing ethnicity data item previously provided by NHS England via the existing Secondary Use Services (SUS) and Second Generation Surveillance System (SGSS) outputs is replaced by the ethnicity data item as held by NHS England within the ‘MI Ethnic Category Coverage’ (MIECC) dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatients (OP), HES Accident and Emergency (A&E, also known as Emergency Care Data Set or ECDS), and General Practice Extraction Service (GPES) Data for Pandemic Planning Research (GDPPR), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SGSS variable

UKHSA have requested that the data item ‘sgtf_under30CT’ (S-gene target failures (SGTF) field) be added to their existing SGSS output, which relates to the English variant of COVID-19. SGTF is an identifier which will help UKHSA understand which Covid-19 variant is present in the data. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so UKHSA can determine if households with the new variant see more transmissions than those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

Changes under Version 4 of this agreement in March 2022:

1. Ethnicity Data

UKHSA are currently receiving ethnicity data item provided by NHS England via the HES APC, HES OP, HES A&E (also known as ECDS), and GDPPR. Within v4 of this agreement, these 4 datasets are to be replaced by the ‘MI (Management Information) Ethnic Category Coverage’ dataset (MIECC). This will provide the same ethnicity data field to the study, with no change to the purpose of use.

2. COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2)

All previous versions of this agreement have included access to COVID-19 Second Generation Surveillance System (SGSS) data. It is anticipated that this dataset will shortly be changing and the new SGSS asset will contain all information relating to Pillar 1 data (people testing for COVID-19 in hospitals only) however the new feed will not contain any data for Pillar 2, which is the COVID-19 testing done within the community (including drive through centres and postal kits etc.) Although it is unknown at which time how soon this change will occur, in order for UKHSA to continue to receive data on COVID-19 testing undertaken within the community, the COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2) dataset has been added to this agreement, with the condition that this dataflow will only commence once SGSS dataflow no longer contains the Pillar 2 information required for this agreement.

Update as of 13/06/2023:

For analytical purposes, UKHSA processes the dataset for the specified epidemiological purposes, which includes data as follows:

- 29,398,476 unique individuals

- 8,187,837 households

- 14,479,933 test-confirmed cases

-- of which, 2,129,425 were secondary cases

UK GDPR Legal Basis for the Data Controller to process the Disclosed Data

The DHSC can rely on UK GDPR Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS England for the above described Purposes. As this is health information and therefore special category personal data the DHSC can also rely on UK GDPR Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the above described Purposes.

NHS England will publish details about the sharing of the Disclosed Data with the UKHSA in its Data Uses Register.

All outputs will be aggregated with small number suppression applied as per the HES analysis guide.

- UKHSA will use the data to produce routine and bespoke reports.

- Analyses have been included in situational awareness reports and briefings which are available to public health agencies and DHSC. HOSTED information has been used by National Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. Analyses have been presented to New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), and subsequently published in academic journals.

- The routine HOSTED outputs are used for internal monitoring reports of the epidemiology of COVI-19, which is part of UKHSA’s situational awareness to monitor for increases in COVID-19.

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to Joint Committee on Vaccination and Immunisation (JCVI) on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. The data has been used to support understanding of the national vaccine programme in reducing onward transmission, with further analyses published since the previous agreement (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9796187/), and work is currently underway to analyses the impact of vaccine booster doses.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles. Work assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

Along with the weekly routine outputs, the modelling cell in UKHSA will use the pseudonymised record level data to undertake household transmission modelling.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to UKHSA will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. There will be no re-identification of individuals by UKHSA.

The record level data set will not be disseminated to other organisations by UKHSA. UKHSA will produce aggregate reports with small number suppression in accordance with the HES analysis guide and Office for National Statistics (ONS) guidance.

HOSTED has had an important impact in understanding the contribution of SARS-CoV-2 vaccines in reducing onward transmission to household contacts of confirmed cases.

A key analysis following the inclusion of vaccination data, demonstrated that the likelihood of household transmission was between 40% - 50% lower in households of index patients who had been vaccinated 21 days or more before testing positive, compared to households of unvaccinated index patients. These findings were reported by the Secretary of State for Health and Social at a national press conference on 28th April 2021 during the initial phase of the vaccine campaign, to reinforce the benefits of vaccination to the public during the vaccine rollout. This analysis was published on the gov.uk website at the time and was later published in The New England Journal of Medicine (NEJM). Prior to publication, findings were shared with the national multi-agency group examining vaccine effectiveness to ensure early awareness among relevant experts.

The advantages of the HOSTED dataset relate to its national coverage of laboratory confirmed cases and rapid assessment of their household contacts, linked to their vaccination status, which allowed the impact of vaccination on household transmission to be quickly assessed. Further work continues to evaluate these effects following expansion of the vaccination programme, with the requested inclusion of further vaccine doses, (following the primary course), being critical to characterising the effects of numbers of vaccination doses, potential waning effects and temporal changes in circulating variants on household transmission. As the vaccination programme has matured and individuals’ vaccination histories become more complex, HOSTED will have critical value in understanding the influence of these factors prospectively. In addition, other work has been undertaken using the HOSTED dataset to assess household risks of hospitalisation among contacts of confirmed cases.

This data has directly benefited the response by informing the UKHSA Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) and Joint Committee on Vaccination and Immunisation (JCVI) expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M-O* and has been published in the NEJM and International Journal of Epidemiology (IJE). It should be noted that the articles published in NEJM and IJE are authored with an employee from University College London (UCL) under secondment to UKHSA to support the national public health response. As an employee on honorary secondment, the author was obliged to follow Information Governance as per any permanent substantive employee.

*SPI-M-O is a sub-group of the Scientific Advisory Group for Emergencies (SAGE) that gives expert advice to the UK government on COVID-19 based on infectious disease modelling and epidemiology

The data continues to be used with current work underway on assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

In addition, analyses of the vaccination in reducing secondary transmission to household contacts during the period of Delta variant dominance have been presented to the National Vaccine Effectiveness review group (attended by public health agency representatives and academics), and since published in Emerging Infectious Diseases (EID)** (https://wwwnc.cdc.gov/eid/article/29/1/22-0996_article). Further analyses are in progress following the inclusion of data on booster doses beyond the primary course, to determine the potential impacts of the booster doses on preventing transmission to household contacts.

**EID is a peer-reviewed, monthly journal published by the Centers for Disease Control and Prevention (CDC)

Data is to be shared for the purpose of supporting a Department of Health and Social Care (DHSC) - UK Health Security Agency (UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

DATA CONTROLLER AND DATA PROCESSOR ROLES

The Controller, for UK GDPR purposes, is the Department of Health and Social Care (DHSC); the legal signatory for this agreement (and for the overarching DSFC) is the Secretary of State for Health and Social Care (acting as part of the Crown), acting through the UK Health Security Agency (hereinafter referred to as UKHSA) within the Department of Health and Social Care; and the licensee is UKHSA, not the wider DHSC.

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care (DHSC). The Agency is the national expert agency responsible with protecting the nation’s health and is responsible for preventing, detecting, analysing, responding to, and leading partnerships to protect the UK from communicable diseases and other threats to public health and acts as the Executive agency for DHSC and as such has operational autonomy from DHSC to fulfil its remit.

The Controller in the application will be shown as the DHSC with the DHSC data sharing framework contract and the DHSC security listed under Security Assurance. The Processor will be shown as UKHSA with the UKHSA DSPT listed under Security Assurance.

UKHSA is an executive agency of DHSC and as such the same legal entity, therefore there are no data processing agreements between DHSC and UKHSA.

The government’s Living with COVID strategy (https://www.gov.uk/government/publications/covid-19-response-living-with-covid-19) remains extant, placing a significant emphasis on the ability to monitor both disease activity and ensuring the vaccination programme provides sufficient protection for the population.

Covid-19 laboratory and case data from UKHSA can be linked to NHS England controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts. HOSTED remains UKHSA’s preferred national dataset to monitor these on a household basis.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of index cases and household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 index cases and household contacts

d) risk factors for Covid-19 among index cases and household contacts

e) deaths from Covid-19 among index cases and household contacts

f) vaccination status of cases of index Covid-19 infection and their household contacts **Added under version 4 of this agreement**

The analysis is for Secondary Use Purposes – the data released for HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Covid-19 remains a potential risk for morbidty and mortality, and the national vaccination programme still operates at this time, so the study requires a further year of dtaa to understand the epidemiology.

Linkage and analysis by NHS England to produce the HOSTED dataset and to support UKHSA to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government.

5. research and planning in relation to Covid-19 including assessing the national COVID-19 vaccination programmes.

The following NHS England data will be accessed:

- COVID-19 Ethnic Category Data Set

- COVID-19 General Practice Extraction Service (GPES) Data for Pandemic Planning and Research (GDPPR)

- COVID-19 Hospitalization in England Surveillance System

- COVID-19 SGSS First Positives (Second Generation Surveillance System)

- COVID-19 UK Non-hospital Antigen Testing Results (Pillar 2)

- COVID-19 Vaccination Status

- Hospital Episode Statistics Accident and Emergency (HES A and E)

- Hospital Episode Statistics Admitted Patient Care (HES APC)

- Hospital Episode Statistics Outpatients (HES OP)

- Personal Demographic Service

- Secondary Uses Service Payment By Results Episodes

Data extracts will be provided on a weekly basis.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

Where individuals have opted out of disease registration by the National Disease Registration Service (NDRS), their data has been permanently removed from the registry and therefore will not be disseminated under this Data Sharing Agreement (DSA). https://digital.nhs.uk/ndrs/patients/opting-out

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS England has agreed to share the data identified with UKHSA (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission surveillance and modelling during the course of the pandemic while SARS-CoV-2 is detected in the population.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts of deaths from Covid-19 among household contacts (including vaccination information).

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by UKHSA for clinical management or intervention at a specific household level.

The Disclosed Data will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared with the UKHSA Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by UKHSA for the purposes of providing routine and bespoke aggregate level small number suppressed reports as per the Hospital Episode Statistics (HES) analysis guide. These are:

- Routine reports to be produced for inclusion in UKHSA epidemiological reporting. These are shared with UKHSA and Department of Health and Social Care (DHSC) colleagues. In addition, results of specific focussed analyses in aggregate format with small numbers supressed are shared with technical experts as relevant, such as in relation to vaccine effectiveness. These reviews by technical experts support dissemination of the scientific findings similar to peer-review publications. In the pandemic situation, it is important to ensure relevant findings are available to experts who may be involved in discussions about interventions such as vaccinations. When these findings are shared, it is only at the level of detail of what would be described in a scientific journal article.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS England and Office for National Statistics guidance. NHS England should be quoted as the source of the Disclosed Data together with other sources.

UKHSA are not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, UKHSA will re-direct them to NHS England who will consider their request.

Changes under version 1 of this agreement in March 2021:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHS England already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHS England in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields for each vaccine dose to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (Index of Multiple Deprivation (IMD)), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts who are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant (differing) vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to UKHSA.

Changes under version 2 of this agreement in May 2021:

1. Enhanced Ethnicity Data

UKHSA have requested that the existing ethnicity data item previously provided by NHS England via the existing Secondary Use Services (SUS) and Second Generation Surveillance System (SGSS) outputs is replaced by the ethnicity data item as held by NHS England within the ‘MI Ethnic Category Coverage’ (MIECC) dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatients (OP), HES Accident and Emergency (A&E, also known as Emergency Care Data Set or ECDS), and General Practice Extraction Service (GPES) Data for Pandemic Planning Research (GDPPR), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SGSS variable

UKHSA have requested that the data item ‘sgtf_under30CT’ (S-gene target failures (SGTF) field) be added to their existing SGSS output, which relates to the English variant of COVID-19. SGTF is an identifier which will help UKHSA understand which Covid-19 variant is present in the data. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so UKHSA can determine if households with the new variant see more transmissions than those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

Changes under Version 4 of this agreement in March 2022:

1. Ethnicity Data

UKHSA are currently receiving ethnicity data item provided by NHS England via the HES APC, HES OP, HES A&E (also known as ECDS), and GDPPR. Within v4 of this agreement, these 4 datasets are to be replaced by the ‘MI (Management Information) Ethnic Category Coverage’ dataset (MIECC). This will provide the same ethnicity data field to the study, with no change to the purpose of use.

2. COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2)

All previous versions of this agreement have included access to COVID-19 Second Generation Surveillance System (SGSS) data. It is anticipated that this dataset will shortly be changing and the new SGSS asset will contain all information relating to Pillar 1 data (people testing for COVID-19 in hospitals only) however the new feed will not contain any data for Pillar 2, which is the COVID-19 testing done within the community (including drive through centres and postal kits etc.) Although it is unknown at which time how soon this change will occur, in order for UKHSA to continue to receive data on COVID-19 testing undertaken within the community, the COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2) dataset has been added to this agreement, with the condition that this dataflow will only commence once SGSS dataflow no longer contains the Pillar 2 information required for this agreement.

Update as of 13/06/2023:

For analytical purposes, UKHSA processes the dataset for the specified epidemiological purposes, which includes data as follows:

- 29,398,476 unique individuals

- 8,187,837 households

- 14,479,933 test-confirmed cases

-- of which, 2,129,425 were secondary cases

UK GDPR Legal Basis for the Data Controller to process the Disclosed Data

The DHSC can rely on UK GDPR Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS England for the above described Purposes. As this is health information and therefore special category personal data the DHSC can also rely on UK GDPR Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the above described Purposes.

NHS England will publish details about the sharing of the Disclosed Data with the UKHSA in its Data Uses Register.

All outputs will be aggregated with small number suppression applied as per the HES analysis guide.

- UKHSA will use the data to produce routine and bespoke reports.

- Analyses have been included in situational awareness reports and briefings which are available to public health agencies and DHSC. HOSTED information has been used by National Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. Analyses have been presented to New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), and subsequently published in academic journals.

- The routine HOSTED outputs are used for internal monitoring reports of the epidemiology of COVI-19, which is part of UKHSA’s situational awareness to monitor for increases in COVID-19.

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to Joint Committee on Vaccination and Immunisation (JCVI) on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. The data has been used to support understanding of the national vaccine programme in reducing onward transmission, with further analyses published since the previous agreement (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9796187/), and work is currently underway to analyses the impact of vaccine booster doses.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles. Work assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

Along with the weekly routine outputs, the modelling cell in UKHSA will use the pseudonymised record level data to undertake household transmission modelling.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to UKHSA will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. There will be no re-identification of individuals by UKHSA.

The record level data set will not be disseminated to other organisations by UKHSA. UKHSA will produce aggregate reports with small number suppression in accordance with the HES analysis guide and Office for National Statistics (ONS) guidance.

HOSTED has had an important impact in understanding the contribution of SARS-CoV-2 vaccines in reducing onward transmission to household contacts of confirmed cases.

A key analysis following the inclusion of vaccination data, demonstrated that the likelihood of household transmission was between 40% - 50% lower in households of index patients who had been vaccinated 21 days or more before testing positive, compared to households of unvaccinated index patients. These findings were reported by the Secretary of State for Health and Social at a national press conference on 28th April 2021 during the initial phase of the vaccine campaign, to reinforce the benefits of vaccination to the public during the vaccine rollout. This analysis was published on the gov.uk website at the time and was later published in The New England Journal of Medicine (NEJM). Prior to publication, findings were shared with the national multi-agency group examining vaccine effectiveness to ensure early awareness among relevant experts.

The advantages of the HOSTED dataset relate to its national coverage of laboratory confirmed cases and rapid assessment of their household contacts, linked to their vaccination status, which allowed the impact of vaccination on household transmission to be quickly assessed. Further work continues to evaluate these effects following expansion of the vaccination programme, with the requested inclusion of further vaccine doses, (following the primary course), being critical to characterising the effects of numbers of vaccination doses, potential waning effects and temporal changes in circulating variants on household transmission. As the vaccination programme has matured and individuals’ vaccination histories become more complex, HOSTED will have critical value in understanding the influence of these factors prospectively. In addition, other work has been undertaken using the HOSTED dataset to assess household risks of hospitalisation among contacts of confirmed cases.

This data has directly benefited the response by informing the UKHSA Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) and Joint Committee on Vaccination and Immunisation (JCVI) expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M-O* and has been published in the NEJM and International Journal of Epidemiology (IJE). It should be noted that the articles published in NEJM and IJE are authored with an employee from University College London (UCL) under secondment to UKHSA to support the national public health response. As an employee on honorary secondment, the author was obliged to follow Information Governance as per any permanent substantive employee.

*SPI-M-O is a sub-group of the Scientific Advisory Group for Emergencies (SAGE) that gives expert advice to the UK government on COVID-19 based on infectious disease modelling and epidemiology

The data continues to be used with current work underway on assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

In addition, analyses of the vaccination in reducing secondary transmission to household contacts during the period of Delta variant dominance have been presented to the National Vaccine Effectiveness review group (attended by public health agency representatives and academics), and since published in Emerging Infectious Diseases (EID)** (https://wwwnc.cdc.gov/eid/article/29/1/22-0996_article). Further analyses are in progress following the inclusion of data on booster doses beyond the primary course, to determine the potential impacts of the booster doses on preventing transmission to household contacts.

**EID is a peer-reviewed, monthly journal published by the Centers for Disease Control and Prevention (CDC)

Progress was previously delayed due to the delays in confirming the last renewal of this DSA and re-establishing data flows.

Data is to be shared for the purpose of supporting a Department of Health and Social Care (DHSC) - UK Health Security Agency (UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

DATA CONTROLLER AND DATA PROCESSOR ROLES

The Controller, for UK GDPR purposes, is the Department of Health and Social Care (DHSC); the legal signatory for this agreement (and for the overarching DSFC) is the Secretary of State for Health and Social Care (acting as part of the Crown), acting through the UK Health Security Agency (hereinafter referred to as UKHSA) within the Department of Health and Social Care; and the licensee is UKHSA, not the wider DHSC.

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care (DHSC). The Agency is the national expert agency responsible with protecting the nation’s health and is responsible for preventing, detecting, analysing, responding to, and leading partnerships to protect the UK from communicable diseases and other threats to public health and acts as the Executive agency for DHSC and as such has operational autonomy from DHSC to fulfil its remit.

The Controller in the application will be shown as the DHSC with the DHSC data sharing framework contract and the DHSC security listed under Security Assurance. The Processor will be shown as UKHSA with the UKHSA DSPT listed under Security Assurance.

UKHSA is an executive agency of DHSC and as such the same legal entity, therefore there are no data processing agreements between DHSC and UKHSA.

The government’s Living with COVID strategy (https://www.gov.uk/government/publications/covid-19-response-living-with-covid-19) remains extant, placing a significant emphasis on the ability to monitor both disease activity and ensuring the vaccination programme provides sufficient protection for the population.

Covid-19 laboratory and case data from UKHSA can be linked to NHS England controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts. HOSTED remains UKHSA’s preferred national dataset to monitor these on a household basis.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of index cases and household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 index cases and household contacts

d) risk factors for Covid-19 among index cases and household contacts

e) deaths from Covid-19 among index cases and household contacts

f) vaccination status of cases of index Covid-19 infection and their household contacts **Added under version 4 of this agreement**

The analysis is for Secondary Use Purposes – the data released for HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Covid-19 remains a potential risk for morbidty and mortality, and the national vaccination programme still operates at this time, so the study requires a further year of dtaa to understand the epidemiology.

Linkage and analysis by NHS England to produce the HOSTED dataset and to support UKHSA to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government.

5. research and planning in relation to Covid-19 including assessing the national COVID-19 vaccination programmes.

The following NHS England data will be accessed:

- COVID-19 Ethnic Category Data Set

- COVID-19 General Practice Extraction Service (GPES) Data for Pandemic Planning and Research (GDPPR)

- COVID-19 Hospitalization in England Surveillance System

- COVID-19 SGSS First Positives (Second Generation Surveillance System)

- COVID-19 UK Non-hospital Antigen Testing Results (Pillar 2)

- COVID-19 Vaccination Status

- Hospital Episode Statistics Accident and Emergency (HES A and E)

- Hospital Episode Statistics Admitted Patient Care (HES APC)

- Hospital Episode Statistics Outpatients (HES OP)

- Personal Demographic Service

- Secondary Uses Service Payment By Results Episodes

Data extracts will be provided on a weekly basis.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

Where individuals have opted out of disease registration by the National Disease Registration Service (NDRS), their data has been permanently removed from the registry and therefore will not be disseminated under this Data Sharing Agreement (DSA). https://digital.nhs.uk/ndrs/patients/opting-out

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS England has agreed to share the data identified with UKHSA (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission surveillance and modelling during the course of the pandemic while SARS-CoV-2 is detected in the population.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts of deaths from Covid-19 among household contacts (including vaccination information).

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by UKHSA for clinical management or intervention at a specific household level.

The Disclosed Data will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared with the UKHSA Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by UKHSA for the purposes of providing routine and bespoke aggregate level small number suppressed reports as per the Hospital Episode Statistics (HES) analysis guide. These are:

- Routine reports to be produced for inclusion in UKHSA epidemiological reporting. These are shared with UKHSA and Department of Health and Social Care (DHSC) colleagues. In addition, results of specific focussed analyses in aggregate format with small numbers supressed are shared with technical experts as relevant, such as in relation to vaccine effectiveness. These reviews by technical experts support dissemination of the scientific findings similar to peer-review publications. In the pandemic situation, it is important to ensure relevant findings are available to experts who may be involved in discussions about interventions such as vaccinations. When these findings are shared, it is only at the level of detail of what would be described in a scientific journal article.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS England and Office for National Statistics guidance. NHS England should be quoted as the source of the Disclosed Data together with other sources.

UKHSA are not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, UKHSA will re-direct them to NHS England who will consider their request.

Changes under version 1 of this agreement in March 2021:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHS England already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHS England in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields for each vaccine dose to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (Index of Multiple Deprivation (IMD)), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts who are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant (differing) vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to UKHSA.

Changes under version 2 of this agreement in May 2021:

1. Enhanced Ethnicity Data

UKHSA have requested that the existing ethnicity data item previously provided by NHS England via the existing Secondary Use Services (SUS) and Second Generation Surveillance System (SGSS) outputs is replaced by the ethnicity data item as held by NHS England within the ‘MI Ethnic Category Coverage’ (MIECC) dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatients (OP), HES Accident and Emergency (A&E, also known as Emergency Care Data Set or ECDS), and General Practice Extraction Service (GPES) Data for Pandemic Planning Research (GDPPR), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SGSS variable

UKHSA have requested that the data item ‘sgtf_under30CT’ (S-gene target failures (SGTF) field) be added to their existing SGSS output, which relates to the English variant of COVID-19. SGTF is an identifier which will help UKHSA understand which Covid-19 variant is present in the data. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so UKHSA can determine if households with the new variant see more transmissions than those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

Changes under Version 4 of this agreement in March 2022:

1. Ethnicity Data

UKHSA are currently receiving ethnicity data item provided by NHS England via the HES APC, HES OP, HES A&E (also known as ECDS), and GDPPR. Within v4 of this agreement, these 4 datasets are to be replaced by the ‘MI (Management Information) Ethnic Category Coverage’ dataset (MIECC). This will provide the same ethnicity data field to the study, with no change to the purpose of use.

2. COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2)

All previous versions of this agreement have included access to COVID-19 Second Generation Surveillance System (SGSS) data. It is anticipated that this dataset will shortly be changing and the new SGSS asset will contain all information relating to Pillar 1 data (people testing for COVID-19 in hospitals only) however the new feed will not contain any data for Pillar 2, which is the COVID-19 testing done within the community (including drive through centres and postal kits etc.) Although it is unknown at which time how soon this change will occur, in order for UKHSA to continue to receive data on COVID-19 testing undertaken within the community, the COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2) dataset has been added to this agreement, with the condition that this dataflow will only commence once SGSS dataflow no longer contains the Pillar 2 information required for this agreement.

Update as of 13/06/2023:

For analytical purposes, UKHSA processes the dataset for the specified epidemiological purposes, which includes data as follows:

- 29,398,476 unique individuals

- 8,187,837 households

- 14,479,933 test-confirmed cases

-- of which, 2,129,425 were secondary cases

Version 6 of this agreement in August 2023 was a 3-month extension in order to allow for further discussion between the Data Controllers and NHS England to establish the amendments required to the data requirements, which will manifest in a future amendment to this agreement. No further data is requested during this 3-month period.

*********************

Version 7 of this agreement in January 2024 is a 6-month extension in order to allow for further discussion between the Data Controllers and NHS England to establish the amendments required to the data requirements, which will manifest in a future amendment to this agreement. No further data is requested during this 6-month period.

*********************

UK GDPR Legal Basis for the Data Controller to process the Disclosed Data

The DHSC can rely on UK GDPR Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS England for the above described Purposes. As this is health information and therefore special category personal data the DHSC can also rely on UK GDPR Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the above described Purposes.

NHS England will publish details about the sharing of the Disclosed Data with the UKHSA in its Data Uses Register.

All outputs will be aggregated with small number suppression applied as per the HES analysis guide.

- UKHSA will use the data to produce routine and bespoke reports.

- Analyses have been included in situational awareness reports and briefings which are available to public health agencies and DHSC. HOSTED information has been used by National Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. Analyses have been presented to New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), and subsequently published in academic journals.

- The routine HOSTED outputs are used for internal monitoring reports of the epidemiology of COVI-19, which is part of UKHSA’s situational awareness to monitor for increases in COVID-19.

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to Joint Committee on Vaccination and Immunisation (JCVI) on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. The data has been used to support understanding of the national vaccine programme in reducing onward transmission, with further analyses published since the previous agreement (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9796187/), and work is currently underway to analyses the impact of vaccine booster doses.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles. Work assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

Along with the weekly routine outputs, the modelling cell in UKHSA will use the pseudonymised record level data to undertake household transmission modelling.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to UKHSA will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. There will be no re-identification of individuals by UKHSA.

The record level data set will not be disseminated to other organisations by UKHSA. UKHSA will produce aggregate reports with small number suppression in accordance with the HES analysis guide and Office for National Statistics (ONS) guidance.

HOSTED has had an important impact in understanding the contribution of SARS-CoV-2 vaccines in reducing onward transmission to household contacts of confirmed cases.

A key analysis following the inclusion of vaccination data, demonstrated that the likelihood of household transmission was between 40% - 50% lower in households of index patients who had been vaccinated 21 days or more before testing positive, compared to households of unvaccinated index patients. These findings were reported by the Secretary of State for Health and Social at a national press conference on 28th April 2021 during the initial phase of the vaccine campaign, to reinforce the benefits of vaccination to the public during the vaccine rollout. This analysis was published on the gov.uk website at the time and was later published in The New England Journal of Medicine (NEJM). Prior to publication, findings were shared with the national multi-agency group examining vaccine effectiveness to ensure early awareness among relevant experts.

The advantages of the HOSTED dataset relate to its national coverage of laboratory confirmed cases and rapid assessment of their household contacts, linked to their vaccination status, which allowed the impact of vaccination on household transmission to be quickly assessed. Further work continues to evaluate these effects following expansion of the vaccination programme, with the requested inclusion of further vaccine doses, (following the primary course), being critical to characterising the effects of numbers of vaccination doses, potential waning effects and temporal changes in circulating variants on household transmission. As the vaccination programme has matured and individuals’ vaccination histories become more complex, HOSTED will have critical value in understanding the influence of these factors prospectively. In addition, other work has been undertaken using the HOSTED dataset to assess household risks of hospitalisation among contacts of confirmed cases.

This data has directly benefited the response by informing the UKHSA Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) and Joint Committee on Vaccination and Immunisation (JCVI) expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M-O* and has been published in the NEJM and International Journal of Epidemiology (IJE). It should be noted that the articles published in NEJM and IJE are authored with an employee from University College London (UCL) under secondment to UKHSA to support the national public health response. As an employee on honorary secondment, the author was obliged to follow Information Governance as per any permanent substantive employee.

*SPI-M-O is a sub-group of the Scientific Advisory Group for Emergencies (SAGE) that gives expert advice to the UK government on COVID-19 based on infectious disease modelling and epidemiology

The data continues to be used with current work underway on assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

In addition, analyses of the vaccination in reducing secondary transmission to household contacts during the period of Delta variant dominance have been presented to the National Vaccine Effectiveness review group (attended by public health agency representatives and academics), and since published in Emerging Infectious Diseases (EID)** (https://wwwnc.cdc.gov/eid/article/29/1/22-0996_article). Further analyses are in progress following the inclusion of data on booster doses beyond the primary course, to determine the potential impacts of the booster doses on preventing transmission to household contacts.

**EID is a peer-reviewed, monthly journal published by the Centers for Disease Control and Prevention (CDC)

Progress was previously delayed due to the delays in confirming the last renewal of this DSA and re-establishing data flows.

Data is to be shared for the purpose of supporting a Department of Health and Social Care (DHSC) - UK Health Security Agency (UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

DATA CONTROLLER AND DATA PROCESSOR ROLES

The Controller, for UK GDPR purposes, is the Department of Health and Social Care (DHSC); the legal signatory for this agreement (and for the overarching DSFC) is the Secretary of State for Health and Social Care (acting as part of the Crown), acting through the UK Health Security Agency (hereinafter referred to as UKHSA) within the Department of Health and Social Care; and the licensee is UKHSA, not the wider DHSC.

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care (DHSC). The Agency is the national expert agency responsible with protecting the nation’s health and is responsible for preventing, detecting, analysing, responding to, and leading partnerships to protect the UK from communicable diseases and other threats to public health and acts as the Executive agency for DHSC and as such has operational autonomy from DHSC to fulfil its remit.

The Controller in the application will be shown as the DHSC with the DHSC data sharing framework contract and the DHSC security listed under Security Assurance. The Processor will be shown as UKHSA with the UKHSA DSPT listed under Security Assurance.

UKHSA is an executive agency of DHSC and as such the same legal entity, therefore there are no data processing agreements between DHSC and UKHSA.

The government’s Living with COVID strategy (https://www.gov.uk/government/publications/covid-19-response-living-with-covid-19) remains extant, placing a significant emphasis on the ability to monitor both disease activity and ensuring the vaccination programme provides sufficient protection for the population.

Covid-19 laboratory and case data from UKHSA can be linked to NHS England controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts. HOSTED remains UKHSA’s preferred national dataset to monitor these on a household basis.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of index cases and household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 index cases and household contacts

d) risk factors for Covid-19 among index cases and household contacts

e) deaths from Covid-19 among index cases and household contacts

f) vaccination status of cases of index Covid-19 infection and their household contacts **Added under version 4 of this agreement**

The analysis is for Secondary Use Purposes – the data released for HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Covid-19 remains a potential risk for morbidty and mortality, and the national vaccination programme still operates at this time, so the study requires a further year of dtaa to understand the epidemiology.

Linkage and analysis by NHS England to produce the HOSTED dataset and to support UKHSA to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government.

5. research and planning in relation to Covid-19 including assessing the national COVID-19 vaccination programmes.

The following NHS England data will be accessed:

- COVID-19 Ethnic Category Data Set

- COVID-19 General Practice Extraction Service (GPES) Data for Pandemic Planning and Research (GDPPR)

- COVID-19 Hospitalization in England Surveillance System

- COVID-19 SGSS First Positives (Second Generation Surveillance System)

- COVID-19 UK Non-hospital Antigen Testing Results (Pillar 2)

- COVID-19 Vaccination Status

- Hospital Episode Statistics Accident and Emergency (HES A and E)

- Hospital Episode Statistics Admitted Patient Care (HES APC)

- Hospital Episode Statistics Outpatients (HES OP)

- Personal Demographic Service

- Secondary Uses Service Payment By Results Episodes

Data extracts will be provided on a weekly basis.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS England has agreed to share the data identified with UKHSA (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission surveillance and modelling during the course of the pandemic while SARS-CoV-2 is detected in the population.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts of deaths from Covid-19 among household contacts (including vaccination information).

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by UKHSA for clinical management or intervention at a specific household level.

The Disclosed Data will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared with the UKHSA Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by UKHSA for the purposes of providing routine and bespoke aggregate level small number suppressed reports as per the Hospital Episode Statistics (HES) analysis guide. These are:

- Routine reports to be produced for inclusion in UKHSA epidemiological reporting. These are shared with UKHSA and Department of Health and Social Care (DHSC) colleagues. In addition, results of specific focussed analyses in aggregate format with small numbers supressed are shared with technical experts as relevant, such as in relation to vaccine effectiveness. These reviews by technical experts support dissemination of the scientific findings similar to peer-review publications. In the pandemic situation, it is important to ensure relevant findings are available to experts who may be involved in discussions about interventions such as vaccinations. When these findings are shared, it is only at the level of detail of what would be described in a scientific journal article.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS England and Office for National Statistics guidance. NHS England should be quoted as the source of the Disclosed Data together with other sources.

UKHSA are not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, UKHSA will re-direct them to NHS England who will consider their request.

Changes under version 1 of this agreement in March 2021:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHS England already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHS England in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields for each vaccine dose to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (Index of Multiple Deprivation (IMD)), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts who are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant (differing) vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to UKHSA.

Changes under version 2 of this agreement in May 2021:

1. Enhanced Ethnicity Data

UKHSA have requested that the existing ethnicity data item previously provided by NHS England via the existing Secondary Use Services (SUS) and Second Generation Surveillance System (SGSS) outputs is replaced by the ethnicity data item as held by NHS England within the ‘MI Ethnic Category Coverage’ (MIECC) dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatients (OP), HES Accident and Emergency (A&E, also known as Emergency Care Data Set or ECDS), and General Practice Extraction Service (GPES) Data for Pandemic Planning Research (GDPPR), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SGSS variable

UKHSA have requested that the data item ‘sgtf_under30CT’ (S-gene target failures (SGTF) field) be added to their existing SGSS output, which relates to the English variant of COVID-19. SGTF is an identifier which will help UKHSA understand which Covid-19 variant is present in the data. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so UKHSA can determine if households with the new variant see more transmissions than those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

Changes under Version 4 of this agreement in March 2022:

1. Ethnicity Data

UKHSA are currently receiving ethnicity data item provided by NHS England via the HES APC, HES OP, HES A&E (also known as ECDS), and GDPPR. Within v4 of this agreement, these 4 datasets are to be replaced by the ‘MI (Management Information) Ethnic Category Coverage’ dataset (MIECC). This will provide the same ethnicity data field to the study, with no change to the purpose of use.

2. COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2)

All previous versions of this agreement have included access to COVID-19 Second Generation Surveillance System (SGSS) data. It is anticipated that this dataset will shortly be changing and the new SGSS asset will contain all information relating to Pillar 1 data (people testing for COVID-19 in hospitals only) however the new feed will not contain any data for Pillar 2, which is the COVID-19 testing done within the community (including drive through centres and postal kits etc.) Although it is unknown at which time how soon this change will occur, in order for UKHSA to continue to receive data on COVID-19 testing undertaken within the community, the COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2) dataset has been added to this agreement, with the condition that this dataflow will only commence once SGSS dataflow no longer contains the Pillar 2 information required for this agreement.

***Update as of 13/06/2023:

For analytical purposes, UKHSA processes the dataset for the specified epidemiological purposes, which includes data as follows:

- 29,398,476 unique individuals

- 8,187,837 households

- 14,479,933 test-confirmed cases

-- of which, 2,129,425 were secondary cases***

*********************

Version 6 of this agreement in August 2022 seeks a 3-month extension in order to allow for further discussion between the Data Controllers and NHS England to establish the amendments required to the data requirements, which will manifest in a future amendment to this agreement. No further data is requested during this 3-month period.

*********************

UK GDPR Legal Basis for the Data Controller to process the Disclosed Data

The DHSC can rely on UK GDPR Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS England for the above described Purposes. As this is health information and therefore special category personal data the DHSC can also rely on UK GDPR Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the above described Purposes.

NHS England will publish details about the sharing of the Disclosed Data with the UKHSA in its Data Uses Register.

All outputs will be aggregated with small number suppression applied as per the HES analysis guide.

- UKHSA will use the data to produce routine and bespoke reports.

- Analyses have been included in situational awareness reports and briefings which are available to public health agencies and DHSC. HOSTED information has been used by National Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. Analyses have been presented to New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), and subsequently published in academic journals.

- The routine HOSTED outputs are used for internal monitoring reports of the epidemiology of COVI-19, which is part of UKHSA’s situational awareness to monitor for increases in COVID-19.

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to Joint Committee on Vaccination and Immunisation (JCVI) on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. The data has been used to support understanding of the national vaccine programme in reducing onward transmission, with further analyses published since the previous agreement (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9796187/), and work is currently underway to analyses the impact of vaccine booster doses.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles. Work assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

Along with the weekly routine outputs, the modelling cell in UKHSA will use the pseudonymised record level data to undertake household transmission modelling.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to UKHSA will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. There will be no re-identification of individuals by UKHSA.

The record level data set will not be disseminated to other organisations by UKHSA. UKHSA will produce aggregate reports with small number suppression in accordance with the HES analysis guide and Office for National Statistics (ONS) guidance.

HOSTED has had an important impact in understanding the contribution of SARS-CoV-2 vaccines in reducing onward transmission to household contacts of confirmed cases.

A key analysis following the inclusion of vaccination data, demonstrated that the likelihood of household transmission was between 40% - 50% lower in households of index patients who had been vaccinated 21 days or more before testing positive, compared to households of unvaccinated index patients. These findings were reported by the Secretary of State for Health and Social at a national press conference on 28th April 2021 during the initial phase of the vaccine campaign, to reinforce the benefits of vaccination to the public during the vaccine rollout. This analysis was published on the gov.uk website at the time and was later published in The New England Journal of Medicine (NEJM). Prior to publication, findings were shared with the national multi-agency group examining vaccine effectiveness to ensure early awareness among relevant experts.

The advantages of the HOSTED dataset relate to its national coverage of laboratory confirmed cases and rapid assessment of their household contacts, linked to their vaccination status, which allowed the impact of vaccination on household transmission to be quickly assessed. Further work continues to evaluate these effects following expansion of the vaccination programme, with the requested inclusion of further vaccine doses, (following the primary course), being critical to characterising the effects of numbers of vaccination doses, potential waning effects and temporal changes in circulating variants on household transmission. As the vaccination programme has matured and individuals’ vaccination histories become more complex, HOSTED will have critical value in understanding the influence of these factors prospectively. In addition, other work has been undertaken using the HOSTED dataset to assess household risks of hospitalisation among contacts of confirmed cases.

This data has directly benefited the response by informing the UKHSA Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) and Joint Committee on Vaccination and Immunisation (JCVI) expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M-O* and has been published in the NEJM and International Journal of Epidemiology (IJE). It should be noted that the articles published in NEJM and IJE are authored with an employee from University College London (UCL) under secondment to UKHSA to support the national public health response. As an employee on honorary secondment, the author was obliged to follow Information Governance as per any permanent substantive employee.

*SPI-M-O is a sub-group of the Scientific Advisory Group for Emergencies (SAGE) that gives expert advice to the UK government on COVID-19 based on infectious disease modelling and epidemiology

The data continues to be used with current work underway on assessing the impacts of school-related measures in an ecological analysis on household transmission is currently underway, with an aim of publishing by the end of 2023.

In addition, analyses of the vaccination in reducing secondary transmission to household contacts during the period of Delta variant dominance have been presented to the National Vaccine Effectiveness review group (attended by public health agency representatives and academics), and since published in Emerging Infectious Diseases (EID)** (https://wwwnc.cdc.gov/eid/article/29/1/22-0996_article). Further analyses are in progress following the inclusion of data on booster doses beyond the primary course, to determine the potential impacts of the booster doses on preventing transmission to household contacts.

**EID is a peer-reviewed, monthly journal published by the Centers for Disease Control and Prevention (CDC)

Progress was previously delayed due to the delays in confirming the last renewal of this DSA and re-establishing data flows.

Data is to be shared for the purpose of supporting a UK Department of Health and Social Care (DHSC) - Health Security Agency (UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

DATA CONTROLLER AND DATA PROCESSOR ROLES

The data controller for GDPR purposes is the Department of Health and Social Care (DHSC); the legal signatory for this agreement (and for the overarching DSFC) is the Secretary of State for Health and Social Care (acting as part of the Crown), acting through the UK Health Security Agency (hereinafter referred to as UKHSA) within the Department of Health and Social Care; and the licensee is UKHSA, not the wider DHSC.

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care (DHSC). The Agency is the national expert agency responsible with protecting the nation’s health and is responsible for preventing, detecting, analysing, responding to, and leading partnerships to protect the UK from communicable diseases and other threats to public health and acts as the Executive agency for DHSC and as such has operational autonomy from DHSC to fulfil its remit.

The data controller in the application will be shown as the DHSC with the DHSC data sharing framework contract and the DHSC security listed under Security Assurance. The data processor will be shown as UKHSA with the UKHSA DSPT listed under Security Assurance.

UKHSA is an executive agency of DHSC and as such the same legal entity, therefore there are no data processing agreements between DHSC and UKHSA.

Currently, there is no national data set to support analyses of the epidemiology of Covid-19 infections in households. Covid-19 laboratory and case data from UKHSA can be linked to NHS England -controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 among household contacts

d) risk factors for Covid-19 among household contacts

e) deaths from Covid-19 among household contacts

f) vaccination status of cases of Covid-19 infection and their household contacts **Added under version 4 of this agreement**

The analysis is for Secondary Use Purposes – the data released for HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently.

Linkage and analysis by NHS England to produce the HOSTED dataset and to support UKHSA to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19 including: locating, contacting, screening, flagging and monitoring such patients and collecting information about and providing services in relation to testing, diagnosis, self-isolation, fitness to work, treatment, medical and social interventions and recovery from Covid-19;

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government including providing information to the public about Covid-19 and its effectiveness and information about capacity, medicines, equipment, supplies, services and the workforce within the health services and adult social care services;

5. research and planning in relation to Covid-19

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS England has agreed to share the data identified with UKHSA (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission surveillance and modelling during the course of the pandemic.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts of deaths from Covid-19 among household contacts.

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by UKHSA for clinical management or intervention at a specific household level.

The Disclosed Data will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared with the UKHSA Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by UKHSA for the purposes of providing routine and bespoke aggregate level small number suppressed reports as per the Hospital Episode Statistics (HES) analysis guide.

These are:

- Routine reports to be produced for inclusion in UKHSA epidemiological report. These are shared with UKHSA and Department of Health and Social Care (DHSC) colleagues. In addition, results of specific focussed analyses in aggregate format with small numbers supressed are shared with technical experts as relevant, such as in relation to vaccine effectiveness. These reviews by technical experts support dissemination of the scientific findings similar to peer-review publications. In the pandemic situation, it is important to ensure relevant findings are available to experts who may be involved in discussions about interventions such as vaccinations. When these findings are shared, it is only at the level of detail of what would be described in a scientific journal article.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS England and Office for National Statistics guidance. NHS England should be quoted as the source of the Disclosed Data together with other sources.

UKHSA are not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, UKHSA will re-direct them to NHS England who will consider their request.

Legal Basis for NHS England to Share the Disclosed Data

The disclosed data is pseudonymised and not confidential. NHS England will publish details about the sharing of the Disclosed Data with the UKHSA in its Data Uses Register.

GDPR Legal Basis for the Data Controller to process the Disclosed Data

The DHSC can rely Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS England for the above described Purposes. As this is health information and therefore special category personal data the DHSC can also rely on Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the above described Purposes.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

***Update as of 18/02/2022:

For analytical purposes, UKHSA processes the dataset for the specified epidemiological purposes, which includes data as follows:

- 24,586,024 unique individuals

- 6,601,071 households

- 11,403,710 test-confirmed cases

-- of which, 1,822,707 were secondary cases***

First amendment to Existing Agreement (version 1 - MARCH 2021)

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHSD already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHSD in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields for each vaccine dose to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (Index of Multiple Deprivation (IMD)), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts who are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant (differing) vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to UKHSA.

Second Amendment to Existing Agreement: (version 2 - MAY 2021)

1. Enhanced Ethnicity Data

UKHSA have requested that the existing ethnicity data item previously provided by NHS England via the existing Secondary Use Services (SUS) and Second Generation Surveillance System (SGSS) outputs is replaced by the ethnicity data item as held by NHS England within the ‘MI Ethnic Category Coverage’ (MIECC) dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatients (OP), HES Accident and Emergency (A&E, also known as Emergency Care Data Set or ECDS), and General Practice Extraction Service (GPES) Data for Pandemic Planning Research (GDPPR), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SGSS variable

UKHSA have requested that the data item ‘sgtf_under30CT’ (S-gene target failures (SGTF) field) be added to their existing SGSS output, which relates to the English variant of COVID-19. SGTF is an identifier which will help UKHSA understand which Covid-19 variant is present in the data. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so UKHSA can determine if households with the new variant see more transmissions than those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

**********

**Third Amendment to Existing Agreement: (version 4 - MARCH 2022)**

1. Ethnicity Data

UKHSA are currently receiving ethnicity data item provided by NHS England via the HES APC, HES OP, HES A&E (also known as ECDS), and GDPPR. Within v4 of this agreement, these 4 datasets are to be replaced by the ‘MI (Management Information) Ethnic Category Coverage’ dataset (MIECC). This will provide the same ethnicity data field to the study, with no change to the purpose of use.

2. COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2)

All previous versions of this agreement have included access to COVID-19 Second Generation Surveillance System (SGSS) data. It is anticipated that this dataset will shortly be changing and the new SGSS asset will contain all information relating to Pillar 1 data (people testing for COVID-19 in hospitals only) however the new feed will not contain any data for Pillar 2, which is the COVID-19 testing done within the community (including drive through centres and postal kits etc.) Although it is unknown at which time how soon this change will occur, in order for UKHSA to continue to receive data on COVID-19 testing undertaken within the community, the COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2) dataset has been added to this agreement, with the condition that this dataflow will only commence once SGSS dataflow no longer contains the Pillar 2 information required for this agreement.

********

All outputs will be aggregated with small number suppression applied as per the HES analysis guide.

- UKHSA will use the data to produce routine and bespoke reports.

- Analyses are included in situational awareness reports and briefings which are available to public health agencies and DHSC.

- The routine HOSTED outputs are expected to be reported weekly into the Epicell report which is circulated to public health agency response teams nationally; these information is used by national Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. One of the underlying factors was later identified to be the novel variant of concern, B.1.1.7 (“Kent variant”). The addition of the SGTF data will enable a more accurate estimation of the impact of this variant and the ability of this surveillance system to contribute to early identification of these changes in the virus. The initial HOSTED analysis was submitted to New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) on the 18th of September 2020 and was subsequently published in the International Journal of Epidemiology (HOSTED—England’s Household Transmission Evaluation Dataset: preliminary findings from a novel passive surveillance system of COVID-19 | International Journal of Epidemiology | Oxford Academic (oup.com)).

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to Joint Committee on Vaccination and Immunisation (JCVI) on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. Further analyses to support understanding of the national vaccine programme in reducing onward transmission is continuing, with an aim to progress these by the end of 2022.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

Along with the weekly routine outputs, the modelling cell in UKHSA will use the pseudonymised record level data to undertake household transmission modelling during the course of the pandemic.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to UKHSA will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. There will be no re-identification of individuals by UKHSA.

The record level data set will not be disseminated to other organisations by UKHSA. UKHSA will produce aggregate reports with small number suppression in accordance with the HES analysis guide and Office for National Statistics (ONS) guidance.

**Last updated March 2022 - Version 4**

HOSTED has had an important impact in understanding the contribution of SARS-CoV-2 vaccines in reducing onward transmission to household contacts of confirmed cases.

A key analysis following the inclusion of vaccination data, demonstrated that the likelihood of household transmission was between 40% - 50% lower in households of index patients who had been vaccinated 21 days or more before testing positive, compared to households of unvaccinated index patients. These findings were reported by the Secretary of State for Health and Social at a national press conference on 28th April 2021 during the initial phase of the vaccine campaign, to reinforce the benefits of vaccination to the public during the vaccine rollout. This analysis was published on the gov.uk website at the time and was later published in The New England Journal of Medicine. Prior to publication, findings were shared with the national multi-agency group examining vaccine effectiveness to ensure early awareness among relevant experts.

The advantages of the HOSTED dataset relate to its national coverage of laboratory confirmed cases and rapid assessment of their household contacts, linked to their vaccination status, which allowed the impact of vaccination on household transmission to be quickly assessed. Further work continues to evaluate these effects following expansion of the vaccination programme, with the requested inclusion of further vaccine doses, (following the primary course), being critical to characterising the effects of numbers of vaccination doses, potential waning effects and temporal changes in circulating variants on household transmission. As the vaccination programme has matured and individuals’ vaccination histories become more complex, HOSTED will have critical value in understanding the influence of these factors prospectively. In addition, other work has been undertaken using the HOSTED dataset to assess household risks of hospitalisation among contacts of confirmed cases.

This data has directly benefited the response by informing the UKHSA Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the NERVTAG and JCVI expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M and has been published in The New England Journal of Medicine (NEJM) and International Journal of Epidemiology (IJE). It should be noted that the articles published in NEJM and IJE are authored with an employee from University College London (UCL) under secondment to UKHSA to support the national public health response. As an employee on honorary secondment, the author was obliged to follow Information Governance as per any permanent substantive employee.

In addition, analyses of the vaccination in reducing secondary transmission to household contacts during the period of Delta variant dominance have been presented to the National Vaccine Effectiveness review group (attended by public health agency representatives and academics). Further analyses are planned following the inclusion of data on booster doses beyond the primary course, to determine the potential impacts of the booster doses on preventing transmission to household contacts.

Data is to be shared for the purpose of supporting a UK Department of Health and Social Care (DHSC) - Health Security Agency (UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

DATA CONTROLLER AND DATA PROCESSOR ROLES

The data controller for GDPR purposes is the Department of Health and Social Care (DHSC); the legal signatory for this agreement (and for the overarching DSFC) is the Secretary of State for Health and Social Care (acting as part of the Crown), acting through the UK Health Security Agency (hereinafter referred to as UKHSA) within the Department of Health and Social Care; and the licensee is UKHSA, not the wider DHSC.

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care (DHSC). The Agency is the national expert agency responsible with protecting the nation’s health and is responsible for preventing, detecting, analysing, responding to, and leading partnerships to protect the UK from communicable diseases and other threats to public health and acts as the Executive agency for DHSC and as such has operational autonomy from DHSC to fulfil its remit.

The data controller in the application will be shown as the DHSC with the DHSC data sharing framework contract and the DHSC security listed under Security Assurance. The data processor will be shown as UKHSA with the UKHSA DSPT listed under Security Assurance.

UKHSA is an executive agency of DHSC and as such the same legal entity, therefore there are no data processing agreements between DHSC and UKHSA.

Currently, there is no national data set to support analyses of the epidemiology of Covid-19 infections in households. Covid-19 laboratory and case data from UKHSA can be linked to NHS Digital-controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 among household contacts

d) risk factors for Covid-19 among household contacts

e) deaths from Covid-19 among household contacts

f) vaccination status of cases of Covid-19 infection and their household contacts **new for version 4 of this agreement**

The analysis is for Secondary Use Purposes – the data released for HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently.

Linkage and analysis by NHS Digital to produce the HOSTED dataset and to support UKHSA to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19 including: locating, contacting, screening, flagging and monitoring such patients and collecting information about and providing services in relation to testing, diagnosis, self-isolation, fitness to work, treatment, medical and social interventions and recovery from Covid-19;

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government including providing information to the public about Covid-19 and its effectiveness and information about capacity, medicines, equipment, supplies, services and the workforce within the health services and adult social care services;

5. research and planning in relation to Covid-19

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS Digital has agreed to share the data identified with UKHSA (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission surveillance and modelling during the course of the pandemic.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts o deaths from Covid-19 among household contacts.

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by UKHSA for clinical management or intervention at a specific household level.

The Disclosed Data will be used by UKHSA to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared with the UKHSA Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by UKHSA for the purposes of providing routine and bespoke aggregate level small number suppressed reports as per the Hospital Episode Statistics (HES) analysis guide.

These are:

- Routine reports to be produced for inclusion in UKHSA epidemiological report. These are shared with UKHSA and Department of Health and Social Care (DHSC) colleagues. In addition, results of specific focussed analyses in aggregate format with small numbers supressed are shared with technical experts as relevant, such as in relation to vaccine effectiveness. These reviews by technical experts support dissemination of the scientific findings similar to peer-review publications. In the pandemic situation, it is important to ensure relevant findings are available to experts who may be involved in discussions about interventions such as vaccinations. When these findings are shared, it is only at the level of detail of what would be described in a scientific journal article.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance. NHS Digital should be quoted as the source of the Disclosed Data together with other sources.

UKHSA are not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, UKHSA will re-direct them to NHS Digital who will consider their request.

Legal Basis for NHS Digital to Share the Disclosed Data

The disclosed data is pseudonymised and not confidential. NHS Digital will publish details about the sharing of the Disclosed Data with the UKHSA in its Data Uses Register.

GDPR Legal Basis for the Data Controller to process the Disclosed Data

The DHSC can rely Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS Digital for the above described Purposes. As this is health information and therefore special category personal data the DHSC can also rely on Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the above described Purposes.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

***Update as of 18/02/2022:

For analytical purposes, UKHSA processes the dataset for the specified epidemiological purposes, which includes data as follows:

- 24,586,024 unique individuals

- 6,601,071 households

- 11,403,710 test-confirmed cases

-- of which, 1,822,707 were secondary cases***

First amendment to Existing Agreement (version 1 - MARCH 2021)

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHSD already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHSD in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields for each vaccine dose to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (Index of Multiple Deprivation (IMD)), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts who are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant (differing) vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to UKHSA.

Second Amendment to Existing Agreement: (version 2 - MAY 2021)

1. Enhanced Ethnicity Data

UKHSA have requested that the existing ethnicity data item previously provided by NHS Digital via the existing Secondary Use Services (SUS) and Second Generation Surveillance System (SGSS) outputs is replaced by the ethnicity data item as held by NHS Digital within the ‘MI Ethnic Category Coverage’ (MIECC) dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatients (OP), HES Accident and Emergency (A&E, also known as Emergency Care Data Set or ECDS), and General Practice Extraction Service (GPES) Data for Pandemic Planning Research (GDPPR), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SGSS variable

UKHSA have requested that the data item ‘sgtf_under30CT’ (S-gene target failures (SGTF) field) be added to their existing SGSS output, which relates to the English variant of COVID-19. SGTF is an identifier which will help UKHSA understand which Covid-19 variant is present in the data. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so UKHSA can determine if households with the new variant see more transmissions than those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

**********

**Third Amendment to Existing Agreement: (version 4 - MARCH 2022)**

1. Ethnicity Data

UKHSA are currently receiving ethnicity data item provided by NHS Digital via the HES APC, HES OP, HES A&E (also known as ECDS), and GDPPR. Within v4 of this agreement, these 4 datasets are to be replaced by the ‘MI (Management Information) Ethnic Category Coverage’ dataset (MIECC). This will provide the same ethnicity data field to the study, with no change to the purpose of use.

2. COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2)

All previous versions of this agreement have included access to COVID-19 Second Generation Surveillance System (SGSS) data. It is anticipated that this dataset will shortly be changing and the new SGSS asset will contain all information relating to Pillar 1 data (people testing for COVID-19 in hospitals only) however the new feed will not contain any data for Pillar 2, which is the COVID-19 testing done within the community (including drive through centres and postal kits etc.) Although it is unknown at which time how soon this change will occur, in order for UKHSA to continue to receive data on COVID-19 testing undertaken within the community, the COVID-19 UK Non-Hospital Antigen Testing Results (pillar 2) dataset has been added to this agreement, with the condition that this dataflow will only commence once SGSS dataflow no longer contains the Pillar 2 information required for this agreement.

********

All outputs will be aggregated with small number suppression applied as per the HES analysis guide.

- UKHSA will use the data to produce routine and bespoke reports.

- Analyses are included in situational awareness reports and briefings which are available to public health agencies and DHSC.

- The routine HOSTED outputs are expected to be reported weekly into the Epicell report which is circulated to public health agency response teams nationally; these information is used by national Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. One of the underlying factors was later identified to be the novel variant of concern, B.1.1.7 (“Kent variant”). The addition of the SGTF data will enable a more accurate estimation of the impact of this variant and the ability of this surveillance system to contribute to early identification of these changes in the virus. The initial HOSTED analysis was submitted to New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) on the 18th of September 2020 and was subsequently published in the International Journal of Epidemiology (HOSTED—England’s Household Transmission Evaluation Dataset: preliminary findings from a novel passive surveillance system of COVID-19 | International Journal of Epidemiology | Oxford Academic (oup.com)).

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to Joint Committee on Vaccination and Immunisation (JCVI) on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. Further analyses to support understanding of the national vaccine programme in reducing onward transmission is continuing, with an aim to progress these by the end of 2022.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

Along with the weekly routine outputs, the modelling cell in UKHSA will use the pseudonymised record level data to undertake household transmission modelling during the course of the pandemic.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to UKHSA will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. There will be no re-identification of individuals by UKHSA.

The record level data set will not be disseminated to other organisations by UKHSA. UKHSA will produce aggregate reports with small number suppression in accordance with the HES analysis guide and Office for National Statistics (ONS) guidance.

**Updated March 2022**

HOSTED has had an important impact in understanding the contribution of SARS-CoV-2 vaccines in reducing onward transmission to household contacts of confirmed cases.

A key analysis following the inclusion of vaccination data, demonstrated that the likelihood of household transmission was between 40% - 50% lower in households of index patients who had been vaccinated 21 days or more before testing positive, compared to households of unvaccinated index patients. These findings were reported by the Secretary of State for Health and Social at a national press conference on 28th April 2021 during the initial phase of the vaccine campaign, to reinforce the benefits of vaccination to the public during the vaccine rollout. This analysis was published on the gov.uk website at the time and was later published in The New England Journal of Medicine. Prior to publication, findings were shared with the national multi-agency group examining vaccine effectiveness to ensure early awareness among relevant experts.

The advantages of the HOSTED dataset relate to its national coverage of laboratory confirmed cases and rapid assessment of their household contacts, linked to their vaccination status, which allowed the impact of vaccination on household transmission to be quickly assessed. Further work continues to evaluate these effects following expansion of the vaccination programme, with the requested inclusion of further vaccine doses, (following the primary course), being critical to characterising the effects of numbers of vaccination doses, potential waning effects and temporal changes in circulating variants on household transmission. As the vaccination programme has matured and individuals’ vaccination histories become more complex, HOSTED will have critical value in understanding the influence of these factors prospectively. In addition, other work has been undertaken using the HOSTED dataset to assess household risks of hospitalisation among contacts of confirmed cases.

This data has directly benefited the response by informing the UKHSA Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the NERVTAG and JCVI expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M and has been published in The New England Journal of Medicine (NEJM) and International Journal of Epidemiology (IJE). It should be noted that the articles published in NEJM and IJE are authored with an employee from University College London (UCL) under secondment to UKHSA to support the national public health response. As an employee on honorary secondment, the author was obliged to follow Information Governance as per any permanent substantive employee.

In addition, analyses of the vaccination in reducing secondary transmission to household contacts during the period of Delta variant dominance have been presented to the National Vaccine Effectiveness review group (attended by public health agency representatives and academics). Further analyses are planned following the inclusion of data on booster doses beyond the primary course, to determine the potential impacts of the booster doses on preventing transmission to household contacts.

Data is to be shared for the purpose of supporting a Department of Health and Social Care – UK Health Security Agency (DHSC – UKHSA) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

Currently, there is no national data set to support analyses of the epidemiology of Covid-19 infections in households. Covid-19 laboratory and case data from DHSC (UKHSA) can be linked to NHS Digital-controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 among household contacts

d) risk factors for Covid-19 among household contacts

e) deaths from Covid-19 among household contacts.

The analysis is for Secondary Use Purpose - HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by DHSC (UKHSA) to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently.

Linkage and analysis by NHS Digital to produce the HOSTED dataset and to support DHSC (UKHSA) to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19 including: locating, contacting, screening, flagging and monitoring such patients and collecting information about and providing services in relation to testing, diagnosis, self-isolation, fitness to work, treatment, medical and social interventions and recovery from Covid-19;

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government including providing information to the public about Covid-19 and its effectiveness and information about capacity, medicines, equipment, supplies, services and the workforce within the health services and adult social care services;

5. research and planning in relation to Covid-19

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS Digital has agreed to share the data identified with the Recipient and its Processors (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission modelling during the course of the pandemic.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 o secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts o deaths from Covid-19 among household contacts.

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by the Recipient for clinical management or intervention at a specific household level.

The Disclosed Data will be used by the Recipient to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared by the Recipient with the DHSC (UKHSA) Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by the Recipient for the purposes of providing routine and bespoke aggregate level small number suppressed reports. These are:

- Routine reports to be produced for inclusion in the DHSC (UKHSA) surveillance report and for the DHSC (UKHSA) Sitrep on a weekly basis. These are shared with DHSC (UKHSA) and DHSC colleagues.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance. NHS Digital should be quoted as the source of the Disclosed Data together with other sources.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

Legal Basis for NHS Digital to Share the Disclosed Data

The disclosed data is pseudonymised and not confidential. NHS Digital will publish details about the sharing of the Disclosed Data with the Recipient in its Data Release Register.

Legal Basis for the Recipient to receive the Disclosed Data

The disclosed data is pseudonymised and not confidential and therefore the Recipient can rely Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS Digital for the Agreed Purposes. As this is health information and therefore special category personal data the Recipient can also rely on Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the Agreed Purposes.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

Update as of 28/03/2021:

- 6,971,746 individuals.

- 1,811,833 households.

- 2,682,584 total lab confirmed cases.

- 452,681 cases that occur 2-14 days after the first case in the household (secondary cases – key outcome of interest).

**********

Amendment to Existing Agreement:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHSD already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHSD in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (IMD), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts that are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to DHSC (UKHSA).

**********

Second Amendment to Existing Agreement: MARCH 2021

1. Enhanced Ethnicity Data

DHSC (UKHSA) have requested that the existing ethnicity data item previously provided by NHS Digital via the existing SUS and SGSS outputs is replaced by the ethnicity data item as held by NHS Digital within the ‘MI Ethnic Category Coverage’ dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care, HES Outpatients, HES Accident and Emergency, and GPES Data for Pandemic Planning Research (GDPPR)), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SHSS variable

DHSC (UKHSA) have requested that the data item ‘sgtf_under30CT’ (SGTF field) be added to their existing SGSS output, which relates to the English variant of COVID-19. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so DHSC (UKHSA) can determine if households with the new variant see more transmissions that those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

- DHSC (UKHSA) will use the data to produce routine and bespoke reports.

- Analyses are included in situational awareness reports and briefings which are available to public health agencies and DHSC.

- The routine HOSTED outputs are reported weekly into the Epicell report which is circulated to public health agency response teams nationally; these information is used by national Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. One of the underlying factors was later identified to be the novel variant of concern, B.1.1.7 (“Kent variant”). The addition of the SGTF data will enable a more accurate estimation of the impact of this variant and the ability of this surveillance system to contribute to early identification of these changes in the virus. The initial HOSTED analysis was submitted to NERVTAG on the 18th of September 2020 and was subsequently published in the International Journal of Epidemiology (HOSTED—England’s Household Transmission Evaluation Dataset: preliminary findings from a novel passive surveillance system of COVID-19 | International Journal of Epidemiology | Oxford Academic (oup.com)).

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to JCVI on March 30th 2021 and initial analysis has been published on gov.uk at the request of the Department of Health and Social Care and also in The New England Journal of Medicine. Further analyses to support understanding of the national vaccine programme in reducing onward transmission is continuing, with an aim to progress these by the end of 2021.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

- All reports will all be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance.

Along with the weekly routine outputs, the modelling cell in DHSC (UKHSA) will use the pseudonymised record level data to undertake household transmission modelling during the course of the pandemic.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to DHSC (UKHSA) will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. At no point will an identifiable linked dataset be produced; so no Duty of Care will be owed or could be acted upon.

The record level data set will not be disseminated to other organisations by DHSC (UKHSA). DHSC (UKHSA) will produce aggregate reports with small number suppression.

This data has directly benefited the response by informing the DHSC (UKHSA) Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the NERVTAG and JCVI expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures. HOSTED has been used to demonstrate the benefits of vaccination in reducing secondary transmission to household contacts; this information has been provided to JCVI and SPI-M and has been published in The New England Journal of Medicine.

Data is to be shared for the purpose of supporting a Public Health England (PHE) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

Currently, there is no national data set to support analyses of the epidemiology of Covid-19 infections in households. Covid-19 laboratory and case data from PHE can be linked to NHS Digital-controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 among household contacts

d) risk factors for Covid-19 among household contacts

e) deaths from Covid-19 among household contacts.

The analysis is for Secondary Use Purpose - HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by PHE to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently.

Linkage and analysis by NHS Digital to produce the HOSTED dataset and to support PHE to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of conditions with or at risk of Covid-19 including: locating, contacting, screening, flagging and monitoring such patients and collecting information about and providing services in relation to testing, diagnosis, self-isolation, fitness to work, treatment, medical and social interventions and recovery from Covid-19;

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government including providing information to the public about Covid-19 and its effectiveness and information about capacity, medicines, equipment, supplies, services and the workforce within the health services and adult social care services;

5. research and planning in relation to Covid-19

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS Digital has agreed to share the data identified with the Recipient and its Processors (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission modelling during the course of the pandemic.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 o secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts o deaths from Covid-19 among household contacts.

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by the Recipient for clinical management or intervention at a specific household level.

The Disclosed Data will be used by the Recipient to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared by the Recipient with the PHE Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by the Recipient for the purposes of providing routine and bespoke aggregate level small number suppressed reports. These are:

- Routine reports to be produced for inclusion in the PHE surveillance report and for the PHE Sitrep on a weekly basis. These are shared with PHE and DHSC colleagues.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance. NHS Digital should be quoted as the source of the Disclosed Data together with other sources.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

Legal Basis for NHS Digital to Share the Disclosed Data

The disclosed data is pseudonymised and not confidential. NHS Digital will publish details about the sharing of the Disclosed Data with the Recipient in its Data Release Register.

Legal Basis for the Recipient to receive the Disclosed Data

The disclosed data is pseudonymised and not confidential and therefore the Recipient can rely Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS Digital for the Agreed Purposes. As this is health information and therefore special category personal data the Recipient can also rely on Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the Agreed Purposes.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

Update as of 28/03/2021:

- 6,971,746 individuals.

- 1,811,833 households.

- 2,682,584 total lab confirmed cases.

- 452,681 cases that occur 2-14 days after the first case in the household (secondary cases – key outcome of interest).

**********

Amendment to Existing Agreement:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHSD already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHSD in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (IMD), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts that are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to PHE.

**********

Second Amendment to Existing Agreement: MARCH 2021

1. Enhanced Ethnicity Data

PHE have requested that the existing ethnicity data item previously provided by NHS Digital via the existing SUS and SGSS outputs is replaced by the ethnicity data item as held by NHS Digital within the ‘MI Ethnic Category Coverage’ dataset (https://digital.nhs.uk/data-and-information/publications/statistical/mi-ethnic-category-coverage/current).

This data item is taken directly from one of four other datasets (Hospital Episode Statistics (HES) Admitted Patient Care, HES Outpatients, HES Accident and Emergency, and GPES Data for Pandemic Planning Research (GDPPR)), depending the level of quality of the ethnicity data items within each of these datasets. Therefore each record will contain an ethnicity data item as sourced from the four datasets where the quality of that ethnicity data item is highest.

2. Extra SHSS variable

PHE have requested that the data item ‘sgtf_under30CT’ (SGTF field) be added to their existing SGSS output, which relates to the English variant of COVID-19. The HOSTED dataset will be amended with this data on which patients had the new “Kent variant”. This allows the HOSTED data to be amended correctly so PHE can determine if households with the new variant see more transmissions that those with the other types of covid-19. This will enable a more accurate estimate of the variant’s transmissibility.

- PHE will use the data to produce routine and bespoke reports.

- Analyses are included in situational awareness reports and briefings which are available to public health agencies and DHSC.

- The routine HOSTED outputs are reported weekly into the Epicell report which is circulated to public health agency response teams nationally; these information is used by national Incident Directors to provide advice to government and were an early signal of the increase in household transmission in late 2020. One of the underlying factors was later identified to be the novel variant of concern, B.1.1.7 (“Kent variant”). The addition of the SGTF data will enable a more accurate estimation of the impact of this variant and the ability of this surveillance system to contribute to early identification of these changes in the virus. The initial HOSTED analysis was submitted to NERVTAG on the 18th of September 2020 and was subsequently published in the International Journal of Epidemiology (HOSTED—England’s Household Transmission Evaluation Dataset: preliminary findings from a novel passive surveillance system of COVID-19 | International Journal of Epidemiology | Oxford Academic (oup.com)).

- Current analysis of the HOSTED data linked to vaccines has been used to establish the effectiveness of the vaccine programme in reducing secondary transmission. These data were presented to JCVI on March 30th 2021 and are being prepared for publication currently.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

- All reports will all be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance.

Along with the weekly routine outputs, the modelling cell in PHE will use the pseudonymised record level data to undertake household transmission modelling during the course of the pandemic.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to PHE will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. At no point will an identifiable linked dataset be produced; so no Duty of Care will be owed or could be acted upon.

The record level data set will not be disseminated to other organisations by PHE. PHE will produce aggregate reports with small number suppression.

This data has directly benefited the response by informing the PHE Incident Director via the routine outputs within the Epicell report. Analysis of the HOSTED data showed the increases in secondary transmission in the South East of England prior to the identification of the “Kent variant”. The analysis has been used by both the NERVTAG and JCVI expert groups who advise the government. The findings are being published in peer reviewed journals when time allows. HOSTED will also be used to establish the impact of school closures.

Data is to be shared for the purpose of supporting a Public Health England (PHE) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

Currently, there is no national data set to support analyses of the epidemiology of Covid-19 infections in households. Covid-19 laboratory and case data from PHE can be linked to NHS Digital-controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 among household contacts

d) risk factors for Covid-19 among household contacts

e) deaths from Covid-19 among household contacts.

The analysis is for Secondary Use Purpose - HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by PHE to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently.

Linkage and analysis by NHS Digital to produce the HOSTED dataset and to support PHE to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of patients with or at risk of Covid-19 including: locating, contacting, screening, flagging and monitoring such patients and collecting information about and providing services in relation to testing, diagnosis, self-isolation, fitness to work, treatment, medical and social interventions and recovery from Covid-19;

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government including providing information to the public about Covid-19 and its effectiveness and information about capacity, medicines, equipment, supplies, services and the workforce within the health services and adult social care services;

5. research and planning in relation to Covid-19

NHS Digital is the Controller for the data which has been requested by the Recipient. The data to be shared by NHS Digital with the Recipient itself does not identify individual patients but in some cases where there are small numbers of individuals represented in the data for certain data fields, it may be possible for the Recipient to identify individual patients. The underlying data which has been analysed and linked by NHS Digital to produce the data to be shared is comprised of information that is identifiable data that has been obtained by the NHS and NHS Digital, in confidence. It also provides information about the health of the patients. The data is therefore considered to be confidential information and subject to a duty of confidence under the common law.

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS Digital has agreed to share the data identified with the Recipient and its Processors (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission modelling during the course of the pandemic.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 o secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts o deaths from Covid-19 among household contacts.

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by the Recipient for clinical management or intervention at a specific household level.

The Disclosed Data will be used by the Recipient to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared by the Recipient with the PHE Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by the Recipient for the purposes of providing routine and bespoke aggregate level small number suppressed reports. These are:

- Routine reports to be produced for inclusion in the PHE surveillance report and for the PHE Sitrep on a weekly basis. These are shared with PHE and DHSC colleagues.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance. NHS Digital should be quoted as the source of the Disclosed Data together with other sources.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

Legal Basis for NHS Digital to Share the Disclosed Data

NHS Digital is able to share Disclosed Data with the Recipient for the Agreed Purposes under a notice issued to NHS Digital by the Secretary of State for Health and Social Care under Regulation 3(4) of the Health Service Control of Patient Information Regulations (COPI) dated 17 March 2020 (the NHSD COPI Notice), as the Recipient is an organisation covered by Regulation 3(3) of COPI and the Agreed Purposes for which the Disclosed Data is being shared is covered by Regulation 3(1) of COPI. Under GDPR, NHS Digital is relying on Article 6(1)(c) – Legal Obligation, to share the Disclosed Data with the Recipient for the Agreed Purposes above. As this is health information and therefore special category personal data NHS Digital is also relying on Article 9(2)(g) – substantial public interest and para 6 of Schedule 1 DPA – statutory purpose, to share the Disclosed Data for the Agreed Purposes. NHS Digital will publish details about the sharing of the Disclosed Data with the Recipient in its Data Release Register.

Legal Basis for the Recipient to receive the Disclosed Data

The Recipient is able to receive and process the Disclosed Data under a notice issued to the Recipient by the Secretary of State for Health and Social Care under Regulation 3(4) of COPI dated 20th March (the Recipient COPI Notice). The Recipient can also receive and process the Disclosed Data for the Agreed Purposes under COPI, as it is an organisation covered by Regulation 3(3) and the Agreed Purposes for which the Disclosed Data is being shared are covered by Regulation 3(1) of COPI. Under GDPR, the Recipient can rely on Article 6(1)(c) – Legal Obligation and Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS Digital for the Agreed Purposes under the Recipient COPI Notice and under COPI. As this is health information and therefore special category personal data the Recipient can also rely on Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the Agreed Purposes.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

**********

Amendment to Existing Agreement:

The HOSTED system provides a unique opportunity to evaluate the impact of any vaccine on transmission. Existing vaccine phase 3 studies identify whether people are likely to become ill with Covid19. These studies do not confirm whether the vaccine eliminates infection altogether or whether it simply reduces clinical severity.

NHSD already holds the core HOSTED dataset. When the Covid 19 vaccine is rolled out the vaccination status of recipients will be retained centrally by NHSD in the National Immunisation Management System (NIMS). This will enable the addition of a “date of vaccine dose” “eligibility for vaccine” “risk group” and “date invited” fields to the HOSTED dataset. The HOSTED dataset is used to monitor the rates and risks of household transmission. This linkage will enable live monitoring of the impact of the vaccine on the population. It would allow stratified analysis by age, ethnicity and prior infection status.

Without this amendment to include vaccinations data it will not be possible to monitor the effect of the vaccine on household transmission, or trends across the pre- and post-vaccine periods due to the impact of vaccination at a national level. The scale of the HOSTED system will enable evaluation within sub groups.

Currently, routine reports include trends in the proportion of household contacts who become cases within 2-14 days of the index case in the same household, stratified by age, region and other relevant covariates. These trends will be presented by vaccination status.

Multivariable modelling is also conducted to simultaneously estimate (and control for) the effects of demographic variables, socio-economic status (IMD), geography and household composition on secondary transmission within households. This will be extended to include the impact of vaccination on secondary transmission, and how this might vary across specific subgroups (such as age, geography and household transmission). These effects will be assessed via interaction terms or stratified analysis, as appropriate.

In the event that the effect of vaccination is confounded with age, IMD, geography or some complex combination of variables, a matched case-control study will be conducted to ensure that these factors are balanced between vaccinated and unvaccinated groups. Analyses may also be restricted to specific groups to answer key policy questions: for instance, couples, older household contacts living in multi-generational houses, parents and their children.

There are two facets to the impact of vaccination:

1. Protection: the protection of vaccinated household contacts that are exposed via a case in their household

2. Transmission: the reduction in infectiousness of index cases who have been vaccinated.

This results in 4 potential groups: both index case and contact not vaccinated, discordant vaccination status for index case/contact (2 groups), and both vaccinated. Preliminary analyses will be conducted to determine the importance of these effects and whether/how the effect on protection needs to be accounted for to estimate the effect on transmission. The effects may combine multiplicatively in terms of the odds of becoming a secondary case, or may interact (i.e., need to be considered as 4 distinct groups).

Although vaccine efficacy (protection) has been established in trials (at around 90%) and will be analysed through other channels, it is worth comparing this within the HOSTED dataset and in the context of household transmission. The effect of vaccination on onward transmission within households is unique to HOSTED, although due to the potential rarity of vaccinated individuals who become index cases (assuming 90% efficacy) power may be low for some comparisons. This will be evaluated as data come in through the surveillance system.

Finally, the analyses described above initially considered vaccination status to be binary. However, the effect of vaccination on both protection and transmission may decline over time, and timing of vaccination in both index cases and contact need be considered. Duration will initially be divided into 3-month groups, and the potential impact of timing on both protection and transmission considered, depending on available sample sizes and the observed relationships.

These changes are legally permitted under the existing regulation 3 powers granted to PHE.

- PHE will use the data to produce routine and bespoke reports.

- Routine reports will be produced for inclusion in the PHE surveillance report and for the PHE Sitrep on a weekly basis. These are shared with PHE and DHSC colleagues.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

- All reports will all be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance.

Along with the weekly routine outputs, the modelling cell in PHE will use the pseudonymised record level data to undertake household transmission modelling during the course of the pandemic.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to PHE will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. At no point will an identifiable linked dataset be produced; so no Duty of Care will be owed or could be acted upon.

The record level data set will not be disseminated to other organisations by PHE. PHE will produce aggregate reports with small number suppression.

Data is to be shared for the purpose of supporting a Public Health England (PHE) surveillance system on household transmission of COVID-19 to enhance the national public health surveillance of Covid-19 infections in the population of England as explained in more detail below.

Currently, there is no national data set to support analyses of the epidemiology of Covid-19 infections in households. Covid-19 laboratory and case data from PHE can be linked to NHS Digital-controlled data sets using one-way encrypted versions of the NHS Number and Unique Property Reference Number to identify the household contacts of Covid-19 patients. This linked data set (called ‘HOSTED’) will be used to establish the Covid-19 status and associated outcomes of these household contacts.

Specifically, the HOSTED data set will be used to identify:

a) the testing status of household contacts

b) secondary cases of Covid-19 infection among household contacts

c) hospital admissions for Covid-19 among household contacts

d) risk factors for Covid-19 among household contacts

e) deaths from Covid-19 among household contacts.

The analysis is for Secondary Use Purpose - HOSTED will not be used for Direct Care purposes.

The HOSTED dataset will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. But it will be used by PHE to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently.

Linkage and analysis by NHS Digital to produce the HOSTED dataset and to support PHE to undertake the following public health surveillance purposes:

1. understanding Covid-19 and risks to public health, trends in Covid-19 and such risks, and controlling and preventing the spread of Covid-19 and such risks;

2. identifying and understanding information about patients or potential patients with or at risk of Covid-19, information about incidents of patient exposure to Covid-19 and the management of patients with or at risk of Covid-19 including: locating, contacting, screening, flagging and monitoring such patients and collecting information about and providing services in relation to testing, diagnosis, self-isolation, fitness to work, treatment, medical and social interventions and recovery from Covid-19;

3. understanding information about patient access to health services and adult social care services as a direct or indirect result of Covid-19 and the availability and capacity of those services;

4. monitoring and managing the response to Covid-19 by health and social care bodies and the Government including providing information to the public about Covid-19 and its effectiveness and information about capacity, medicines, equipment, supplies, services and the workforce within the health services and adult social care services;

5. research and planning in relation to Covid-19

NHS Digital is the Controller for the data which has been requested by the Recipient. The data to be shared by NHS Digital with the Recipient itself does not identify individual patients but in some cases where there are small numbers of individuals represented in the data for certain data fields, it may be possible for the Recipient to identify individual patients. The underlying data which has been analysed and linked by NHS Digital to produce the data to be shared is comprised of information that is identifiable data that has been obtained by the NHS and NHS Digital, in confidence. It also provides information about the health of the patients. The data is therefore considered to be confidential information and subject to a duty of confidence under the common law.

The purposes for sharing the requested data are set out below (Agreed Purposes):

- NHS Digital has agreed to share the data identified with the Recipient and its Processors (as defined in GDPR) identified below to support the analyses of the epidemiology of Covid-19 infections in households and to undertake household transmission modelling during the course of the pandemic.

- The Disclosed Data will not contain any patient identifiers and will comprise of a pseudonymised dataset which will identify: the testing status of household contacts of patients diagnosed with COVID-19 o secondary cases of Covid-19 infection among household contacts, hospital admissions for Covid-19 among household contacts and risk factors for Covid-19 among household contacts o deaths from Covid-19 among household contacts.

The Disclosed Data will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. Taking action at a specific individual household level would be inappropriate and unsafe given that there will be errors in the data. This is tolerable for a surveillance system but not for a clinical management system. The Disclosed Data will not and should not be used by the Recipient for clinical management or intervention at a specific household level.

The Disclosed Data will be used by the Recipient to enhance the national public health surveillance of Covid-19 by enabling a range of longitudinal analyses of the epidemiology of the infection which are not possible currently. Where any significant findings are made that would warrant advice on policy, these will be shared by the Recipient with the PHE Incident Director as part of the incident response who would incorporate this into the advice to government as appropriate.

• Aggregate level data from analysis of the Disclosed Data will be shared by the Recipient for the purposes of providing routine and bespoke aggregate level small number suppressed reports. These are:

- Routine reports to be produced for inclusion in the PHE surveillance report and for the PHE Sitrep on a weekly basis. These are shared with PHE and DHSC colleagues.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

All such reports produced will be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance. NHS Digital should be quoted as the source of the Disclosed Data together with other sources.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

The Recipient is not permitted to share the Disclosed Data with any third parties, except to the extent set out above. Should any third party wish to have access to the Disclosed Data, the Recipient will re-direct them to NHS Digital who will consider their request.

Legal Basis for NHS Digital to Share the Disclosed Data

NHS Digital is able to share Disclosed Data with the Recipient for the Agreed Purposes under a notice issued to NHS Digital by the Secretary of State for Health and Social Care under Regulation 3(4) of the Health Service Control of Patient Information Regulations (COPI) dated 17 March 2020 (the NHSD COPI Notice), as the Recipient is an organisation covered by Regulation 3(3) of COPI and the Agreed Purposes for which the Disclosed Data is being shared is covered by Regulation 3(1) of COPI. Under GDPR, NHS Digital is relying on Article 6(1)(c) – Legal Obligation, to share the Disclosed Data with the Recipient for the Agreed Purposes above. As this is health information and therefore special category personal data NHS Digital is also relying on Article 9(2)(g) – substantial public interest and para 6 of Schedule 1 DPA – statutory purpose, to share the Disclosed Data for the Agreed Purposes. NHS Digital will publish details about the sharing of the Disclosed Data with the Recipient in its Data Release Register.

Legal Basis for the Recipient to receive the Disclosed Data

The Recipient is able to receive and process the Disclosed Data under a notice issued to the Recipient by the Secretary of State for Health and Social Care under Regulation 3(4) of COPI dated 20th March (the Recipient COPI Notice). The Recipient can also receive and process the Disclosed Data for the Agreed Purposes under COPI, as it is an organisation covered by Regulation 3(3) and the Agreed Purposes for which the Disclosed Data is being shared are covered by Regulation 3(1) of COPI. Under GDPR, the Recipient can rely on Article 6(1)(c) – Legal Obligation and Article 6(1)(e) public task, to receive and process the Disclosed Data from NHS Digital for the Agreed Purposes under the Recipient COPI Notice and under COPI. As this is health information and therefore special category personal data the Recipient can also rely on Article 9(2)(i) – public health purposes, plus Part 1, Sched 1 DPA18, para 3 public health to process the Disclosed Data for the Agreed Purposes.

Cohort information

The precise number of records will not be known until the asset is built and will depend on the number of cases.

As a rough estimate for illustrative purposes, as at 22 April 2020, there have been ~99,000 diagnosed cases in England. Assuming an average household size of 2.4, this would represent ~238,000 individuals living in the same household as a diagnosed case, who would thus be eligible for inclusion in the dataset. This number will grow as the number of diagnoses increases over the course of the epidemic.

- PHE will use the data to produce routine and bespoke reports.

- Routine reports will be produced for inclusion in the PHE surveillance report and for the PHE Sitrep on a weekly basis. These are shared with PHE and DHSC colleagues.

- Additional public-facing reports will also be produced, consisting of surveillance reports and peer-reviewed journal articles.

- All reports will all be at an aggregate level with small numbers suppressed in accordance with NHS Digital and Office for National Statistics guidance.

Along with the weekly routine outputs, the modelling cell in PHE will use the pseudonymised record level data to undertake household transmission modelling during the course of the pandemic.

The HOSTED data set will not be sufficiently accurate for use for direct patient care or enhancing the national shielding programme. This is due to both, accepted errors within surveillance system datasets and the time lag required to generate the full dataset.

The pseudonymised data disseminated to PHE will be used to enhance the national public health surveillance of Covid-19 infections in the population of England. At no point will an identifiable linked dataset be produced; so no Duty of Care will be owed or could be acted upon.

The record level data set will not be disseminated to other organisations by PHE. PHE will produce aggregate reports with small number suppression.

Yielded Benefits is not a requirement for new applications.