Cohort Profile: Longitudinal population-based study of COVID-19 in UK adults (COVIDENCE UK).

Background Coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is estimated to have caused more than 18 million deaths worldwide as of end-May 2022. Methods COVIDENCE UK is a longitudinal population-based study that investigates risk factors for, and impacts of, COVID-19 in UK residents aged ≥16 years. A unique feature is the capacity to support trial-within-cohort studies to evaluate interventions for prevention of COVID-19 and other acute respiratory illnesses. Participants complete a detailed online baseline questionnaire capturing self-reported information relating to their socio-demographic characteristics, occupation, lifestyle, quality of life, weight, height, longstanding medical conditions, medication use, vaccination status, diet and supplemental micronutrient intake. Follow-up on-line questionnaires capturing incident symptoms of COVID-19 and other acute respiratory infections, incident swab test-confirmed COVID-19, doses of SARS-CoV-2 vaccine received, and quality of life are completed at monthly intervals. Results The study was launched on 1st May 2020 and closed to recruitment on 6th October 2021. A total of 19,981 participants enrolled and consented to 5-year follow-up with medical record linkage. Their mean age was 59.1 years (range 16.0 to 94.4 years), 70.2% were female, and 93.7% identified their ethnic origin as White. Analyses conducted to date have provided key insights into risk factors for SARS-CoV-2 infection and COVID-19 disease, determinants of SARS-CoV-2 vaccine immunogenicity and efficacy, and impacts of COVID-19 on health economic outcomes. The cohort has also supported conduct of a Phase 3 randomised trial-within-cohort study (CORONAVIT) evaluating implementation of a test-and-treat approach to correcting sub-optimal vitamin D status on incidence and severity of acute respiratory infections, including COVID-19. Conclusions The COVIDENCE UK dataset represents a valuable resource containing granular information on factors influencing susceptibility to, and impacts of, COVID-19 in UK adults. Researchers wishing to access anonymised participant-level data should contacting the corresponding author for further information. ### Competing Interest Statement JS declares receipt of payments from Reach plc for news stories written about recruitment to and findings of the COVIDENCE UK study. RAL declares membership of the Welsh Government COVID19 Technical Advisory Group. AS and JN declare research infrastructure report to the University of Edinburgh from ISCF/HDR UK. AS is a member of the Scottish Government Chief Medical Officers COVID-19 Advisory Group and its Standing Committee on Pandemics. He is also a member of the UK Governments NERVTAGs Risk Stratification Subgroup. ARM declares receipt of funding in the last 36 months to support vitamin D research from the following companies who manufacture or sell vitamin D supplements: Pharma Nord Ltd DSM Nutritional Products Ltd Thornton & Ross Ltd and Hyphens Pharma Ltd. ARM also declares support for attending meetings from the following companies who manufacture or sell vitamin D supplements: Pharma Nord Ltd and Abiogen Pharma Ltd. ARM also declares receipt of a consultancy fee from DSM Nutritional Products Ltd and a speaker fee from the Linus Pauling Institute. ARM also declares participation on Data and Safety Monitoring Boards for the VITALITY trial (Vitamin D for Adolescents with HIV to reduce musculoskeletal morbidity and immunopathology Pan African Clinical Trials Registry ref PACTR20200989766029) and the Trial of Vitamin D and Zinc Supplementation for Improving Treatment Outcomes Among COVID-19 Patients in India ([ClinicalTrials.gov][1] ref [NCT04641195][2]). ARM also declares unpaid work as a Programme Committee member for the Vitamin D Workshop. ARM also declares receipt of vitamin D capsules for clinical trial use from Pharma Nord Ltd Synergy Biologics Ltd and Cytoplan Ltd. All other authors declare that they have no competing interests. ### Funding Statement COVIDENCE UK is supported by funds granted by Barts Charity (ref. MGU0459), Pharma Nord Ltd, the Fischer Family Foundation, DSM Nutritional Products Ltd, the Exilarchs Foundation, the Karl R Pfleger Foundation, the AIM Foundation, HDR UK, Thornton & Ross Ltd, Warburtons Ltd, Mr Matthew Isaacs (personal donation), Prof Barbara Boucher (personal donation) and Hyphens Pharma Ltd. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: COVIDENCE UK is sponsored by, and located at, Queen Mary University of London. It was funded by Barts Charity (ref MGU0466); approved by Leicester South Research Ethics Committee (ref 20/EM/0117); and prospectively registered with [ClinicalTrials.gov][1] ([NCT04330599][3]). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript [1]: http://ClinicalTrials.gov [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04641195&atom=%2Fmedrxiv%2Fearly%2F2022%2F06%2F24%2F2022.06.20.22276205.atom [3]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04330599&atom=%2Fmedrxiv%2Fearly%2F2022%2F06%2F24%2F2022.06.20.22276205.atom