Prevalence and impact of SARS-CoV-2, influenza, respiratory syncytial virus (RSV) infection and respiratory illness on UK healthcare workers during winter 2023/24 (September 2023 to March 2024): SIREN cohort study

ABSTRACT During the winter, healthcare systems experience additional pressures due to increases in respiratory infections and staff absence. We aimed to determine the prevalence of respiratory viruses and impact on sickness absence in the SIREN healthcare worker (HCW) cohort during winter 2023/24. SIREN is a cohort study with linked testing, vaccination, demographic, symptoms and sick leave data. Participants undergo fortnightly multiplex PCR testing for SARS-CoV-2, influenza and RSV, regardless of symptoms. The proportion of participants who took sick leave, the total number and median of sick leave days taken was calculated by viral infection and vaccination status. Logistic regression was used to estimate the association between sick leave and vaccination status. 5,287 participants were included, 78·3% female, median age 54 years. There were 1,828 infections among 1,659 participants (1,161 SARS-CoV-2; 387 RSV; 280 influenza infections). Influenza and RSV peaked in December (1·2%; 1·9%), SARS-CoV-2 peaked in September and December 2023 (4·0%; 4·3%). Regardless of a known infection, 35.8% (1,892/5,287) took sick leave, resulting in 10,168 days (median 5 days per person; range 1-98 days). Vaccination was not significantly associated with reduced sick leave (adjusted odd ratios 0·98; 95%CI 0·87, 1·10). Respiratory illness caused a substantial burden on the SIREN healthcare workforce over winter, with all three viruses contributing. Reduced number of staff at work and pressures to work through illness have implications for healthcare resilience. Competing Interest Statement The authors have declared no competing interest. Funding Statement The SIREN study was funded by the UK Health Security Agency; the UK Department of Health and Social Care with contributions from the governments in Northern Ireland, Wales, and Scotland. Wellcome Grant reference: 220540/Z/20/A, 'Wellcome Sanger Institute Quinquennial Review 2021-2026. 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: The SIREN study was approved by the Berkshire Research Ethics Committee (IRAS ID 284460, REC Reference 20SC0230) on 22 May 2020. SIREN 2.0 was approved via an amendment on 22 August 2023. Participants returning to the study gave informed consent. Clinical trial registration number: ISRCTN11041050; registration date: 12 January 2021. 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, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability Anonymised data will be made available for secondary analysis to trusted researchers upon reasonable request.