RT Journal Article SR Electronic T1 Burden of nosocomial COVID-19 in Wales: results from a multicentre retrospective observational study of 2508 hospitalised adults JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 1246 OP 1249 DO 10.1136/thoraxjnl-2021-216964 VO 76 IS 12 A1 Ponsford, Mark J A1 Jefferies, Rhys A1 Davies, Chris A1 Farewell, Daniel A1 Humphreys, Ian R A1 Jolles, Stephen A1 Fairbairn, Sara A1 Lewis, Keir A1 Menzies, Daniel A1 Benjamin, Amit A1 Thaivalappil, Favas A1 Williams, Chris A1 Barry, Simon M YR 2021 UL http://thorax.bmj.com/content/76/12/1246.abstract AB The burden of nosocomial SARS-CoV-2 infection remains poorly defined. We report on the outcomes of 2508 adults with molecularly-confirmed SARS-CoV-2 admitted across 18 major hospitals, representing over 60% of those hospitalised across Wales between 1 March and 1 July 2020. Inpatient mortality for nosocomial infection ranged from 38% to 42%, consistently higher than participants with community-acquired infection (31%–35%) across a range of case definitions. Those with hospital-acquired infection were older and frailer than those infected within the community. Nosocomial diagnosis occurred a median of 30 days following admission (IQR 21–63), suggesting a window for prophylactic or postexposure interventions, alongside enhanced infection control measures.