Before revision:  DESIGN : Retrospective cohort, analysed using a matched nested case-control study design. SETTING : Community-based SARS-CoV-2 testing in England, individually linked with hospitalisation data from the Secondary Uses Service and the Emergency Care Data Set. PARTICIPANTS: 493,053 laboratory-confirmed COVID-19 patients, of whom 19,482 had been hospitalised  , tested between 23 November 2020 and 4 January 2021 and analysed at a laboratory with an available TaqPath assay that enables assessment of S-gene target failure (SGTF).
After revision:  DESIGN : Retrospective cohort, analysed using stratified Cox regression. Setting : Community-based SARS-CoV-2 testing in England, individually linked with hospitalisation data from the Secondary Uses Service and the Emergency Care Data Set. PARTICIPANTS: 493,053 laboratory-confirmed COVID-19 patients, of whom 19,482 had been hospitalised , tested between 23 November 2020 and 4 January 2021 and analysed at a laboratory with an available TaqPath assay that enables assessment of S-gene target failure (SGTF).