Does nosocomial COVID-19 result in increased 30-day mortality? A multi-centre observational study to identify risk factors for worse outcomes in patients with COVID-19.

This study aimed to determine whether nosocomial coronavirus disease 2019 (COVID-19) has a worse outcome compared with community-acquired COVID-19. This was a prospective cohort study of all hospitalized patients with confirmed COVID-19 in three acute hospitals on 9 April 2020. Patients were followed-up for at least 30 days. Nosocomial infection was defined as a positive swab after 7 days of admission. In total, one hundred and seventy-three patients were identified, and 19 (11.0%) had nosocomial infection. Thirty-two (18.5%) patients died within 30 days (all cause) of a positive swab test; there were no significant differences in 30-day all-cause mortality rates between the three groups (i.e. patients admitted with suspected COVID-19, patients with incidental COVID-19 and patients with nosocomial COVID-19): 21.1% vs 17.6% vs 21.6% (P=0.755). Nosocomial COVID-19 is not associated with increased mortality compared with community-acquired COVID-19.