Acknowledging the Burden of Nosocomial COVID-19: Results from a Multi-Centre Retrospective Observational Study of 2518 Adults Hospitalised Across the Nation of Wales

Abstract

Background: The burden of hospital-acquired (nosocomial) COVID-19 remains poorly defined with variation in case-definitions used for reporting and little publicly-available information concerning outcomes.Methods: We conducted a retrospective observational study of adult patients with a positive SARS-CoV-2 positive polymerase chain reaction (PCR) hospitalised across Wales between 1st March – 1st July 2020. An electronic survey was used to capture patient outcome following admission until 20th November. The prevalence and outcomes for nosocomial COVID-19 were assessed across of a range of possible case definitions.Findings: The study included 2518 patients from 18 major hospitals sites across Wales and collected outcomes on patients discharged up to 20 th November, representing approximately 60% of patients hospitalised. Inpatient mortality rates for nosocomial COVID-19 ranged from 38% to 42%, and remained consistently higher than patients with community-acquired infection (31% to 35%) across a range of case definitions. Nosocomial patients were older, frailer and multi-morbid population than those with community-acquired disease, even when categorised using a 2-day cut-off. Based on the Public Health Wales case definition of nosocomial COVID-19 infection, 50% of cases had been admitted for 30 days prior to diagnostic testing.Interpretation: This represents the largest assessment of clinical outcomes for patients with nosocomial COVID-19 in the UK to date. These findings suggest that inpatient mortality rates from nosocomial-infection are likely higher than previously reported, emphasizing the importance of infection control measures, and suggests opportunities for inpatient vaccination of vulnerable cohorts.Funding: Welsh Government, Respiratory Health Implementation Group, UK Coronavirus Immunology Consortium, Wellcome Trust Senior Fellowship (to IRH), WCAT Fellowship (to MJP).Declaration of Interests: We declare no competing interests.Ethics Approval Statement: This project constitutes the evaluation/audit arm of the National Pathway for Managing COVID-19 Infections in Secondary Care in Wales. As such, the requirement for formal ethical review or approval was not required