Working under short timescales to deliver a national trial: a case study of the ComFluCOV trial from a statistician's perspective.

"Declarations Ethics approval and consent to participateEthical review and approval was provided by South Central - Berkshire Research Ethics Committee (21/SC/0100) in the UK. Informed consent was received from all study participants. Consent for publicationNot applicable. Competing interestsRL reports grants from the National Institute for Health Research (NIHR) during the conduct of the trial and grants from Elizabeth Blackwell Institute, AstraZeneca, Janssen, and Valneva outside the submitted work. SB, LC, and CAR reports grants from NIHR, during the conduct of the trial. All other authors declare no competing interests. Competing interests RL reports grants from the National Institute for Health Research (NIHR) during the conduct of the trial and grants from Elizabeth Blackwell Institute, AstraZeneca, Janssen, and Valneva outside the submitted work. SB, LC, and CAR reports grants from NIHR, during the conduct of the trial. All other authors declare no competing interests."

"Funding This trial was funded by the National Institute for Health Research Policy Research Programme (PR-R17-0916-22001, NIHR203243). The views in this article are those of the authors and not necessarily those of the UK Department of Health and Social Care. The funders determined which vaccines were used in the trial but had no role in the data collection, data analysis, data interpretation, or writing of the report. COVID-19 vaccines were supplied by Public Heath England, and influenza vaccines were supplied by the DHSC."

"Trial registration ISRCTN14391248, registered on 30 March 2021"