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Creating the Virus Watch dataset

Categories: Office for National Statistics, Health & wellbeing, Research findings, Impact, Data Insights, Policy, Practice, People

1 April 2025

Creating the Virus Watch dataset

Author: Dr Vincent Nguyen

Date: April 2025

Research summary

Virus Watch was a community cohort study of Covid-19, with around 60,000 participants across England and Wales. It ran from June 2020 until April 2025.  Findings from the study have contributed evidence for strategic policymaking by the Joint Committee on Vaccination and Immunisation, for the national booster vaccine campaign, and for the UK Covid-19 Inquiry highlighting the inequities  of the pandemic.  

This household study aimed to provide evidence on which public health approaches are most effective in reducing transmission. It also investigated community incidence, symptoms, and transmission of Covid-19 in relation to population movement and behaviours.

Data created

Virus Watch was a national community cohort study of Covid-19 in households in England and Wales. Run by University College London in conjunction with the NHS, it was established in June 2020 with data collection continuing into the spring of 2025.

The ongoing data collection from over 28,500 households and 58,000 participants from England and Wales was securely collected using the online survey platform, REDCap. To ensure the cohort was representative of England and Wales, in terms of geography and sociodemographic breakdown. Virus Watch employed clustered random sampling for recruitment, supplemented by a targeted equity recruitment drive via social media and through GP clinics.

Data collected included demographics and details of occupation, comorbidities, medications, and infection-prevention behaviours. Households were followed up weekly to complete a survey that captured Covid-19 symptoms and their severity, activities in the week prior to symptom onset, as well as any Covid-19 test results and vaccinations. Additional ad hoc surveys captured household finance, employment, mental health, access to health care, activities, and contacts.

The survey data was linked to Hospital Episode Statistics, inpatient and critical care episodes, outpatient visits, emergency care contacts, mortality, virology testing, and vaccination data held by NHS Digital.

Through the National Institute for Health and Care Research’s Clinical Research Network and the Francis Crick Institute, Virus Watch participants contributed over 12,000 blood serum samples at the beginning of the Covid-19 pandemic. These were tested for spike and nucleocapsid antibodies. The team also collected close to 1000 swab samples that were tested by Polymerase Chain Reaction (PCR) for SARS-CoV-2. These results helped to assess people’s immune response to the virus and to the vaccine, and how this may protect them from future infection.

With the deployment of vaccines, Virus Watch collaborated with the Department of Health and Social Care and Thriva Ltd. to collect 19,555 longitudinal serum micro-samples to evaluate vaccine effectiveness.

Additionally, Virus Watch collaborated with the Great Ormond Street Hospital and the Camelia Botnar labs to invite 2800 individuals to provide PCR swabs, in order to help understand transmission by sequencing positive samples.

In a subset of individuals, Virus Watch also collaborated with the SpaceTimeLab and the Environmental Systems Research Institute to collect geospatial data to study participant mobility pre- and post-Covid-vaccination. Data was collected in a secure manner with participants sharing their location via a global positioning system (GPS). This work resulted in receiving the 2023 Jack Dangermond Young Scholar award.

University College London, released 19 May 2022, ONS SRS Metadata Catalogue, dataset, Virus Watch - England and Wales, https://doi.org/10.57906/s5f5-nq13

Dataset impact

The Virus Watch dataset has produced over 30 peer-reviewed publications and received extensive digital and broadcast media coverage. It has been used to triangulate and externally validate results of researchers who wanted to compare findings from disease-based-population-specific research to those of the general community population in Virus Watch. These publications have been presented to the Scientific Advisory Group for Emergencies (SAGE) and the Joint Committee on Vaccination and Immunisation, contributing to the evidence base for and implementation of policies such as the introduction of booster dose vaccines.

In addition to contributing to the public benefit in Britain, Virus Watch publications have been a part of the United States Centre of Disease Control’s Public Health Genomics and Precision Health Knowledge database. These are pre-selected by the CDC Office of Public Health Genomics to provide current awareness of the literature and news.  Virus Work has also been cited by the Australian Technical Advisory Group on Immunisation. It cites the recommendation for an mRNA booster dose, irrespective of the primary vaccine mechanism of action (e.g. Chimpanzee Adenovirus). Furthermore, research using the Virus Watch data has been used as evidence in the UK Covid-19 Inquiry, particularly the collaboration between Virus Watch, the Race Equality Foundation and Doctors of the World, which demonstrated the inequalities experienced by some groups during the pandemic.

Research outputs

Publications and reports

Blogs, news posts, and videos

Presentations and awards

Parliament/Government references to Virus Watch

  • Written Evidence Virus Watch
  • Third Quarterly report on progress to address COVID-19 health inequalities
  • COVID-19 and Occupational Impacts
  • Technical report on the COVID-19 pandemic in the UK 
  • The Occupational Impact of COVID-19 in the Transport and Education  sectors
  • EQUALITY IMPACT ASSESSMENT – THE HEALTH PROTECTION (CORONAVIRUS) (REQUIREMENTS) (SCOTLAND) AMENDMENT (NO. 6), (NO. 7) AND (NO. 8) REGULATIONS 2021 – DECEMBER 2021
  • Coronavirus: Covid-19 booster vaccines frequently asked questions
  • Australian Technical Advisory Group on Immunisation (ATAGI) recommendations on the use of a booster dose of COVID-19 vaccine

About the Office for National Statistics (ONS) Secure Research Service

The ONS Secure Research Service is an accredited trusted research environment, using the Five Safes Framework to provide secure access to de-identified, unpublished data.

If you use ONS Secure Research Service data and would like to discuss writing a future case study with us, please get in touch at IDS.Impact@ons.gov.uk. Please also report any outputs here: Outputs Reporting Form.

All other authors declare no competing interests. The research costs for the study have been supported by the Medical Research Council Grant awarded to University College London. Virus Watch received support via the Department of Health and Social Care’s Vaccine Evaluation Programme to provide monthly Thriva antibody tests to adult participants. This work was supported by the Wellcome Trust through a Wellcome Clinical Research Career Development Fellowship.

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