Effective control of SARS-CoV-2 transmission between healthcare workers during a period of diminished community prevalence of COVID-19.

Previously we showed that 31/1,032 (3%) asymptomatic healthcare workers (HCW) from a large teaching hospital in Cambridge UK tested positive for SARS-CoV-2 in April 2020. 26/169 (15%) HCWs with symptoms of coronavirus disease 2019 (COVID-19) also tested positive (Rivett et al., 2020). Here we show that the proportion of both asymptomatic and symptomatic HCWs testing positive rapidly declined to near-zero between 25th April and 24th May 2020, corresponding with a decline in patient admissions with COVID-19 during the ongoing UK 'lockdown'. These data demonstrate how infection prevention and control measures including staff testing may help prevent hospitals from becoming independent 'hubs' of SARS-CoV-2 transmission, and illustrate how, with appropriate precautions, organisations in other sectors may be able to resume on-site work safely.