Wearing masks and establishing COVID-19 areas reduces secondary attack risk in nursing homes

Background COVID-19 is spreading rapidly in nursing homes (NHs). It is urgent to evaluate the effect of infection prevention and control (IPC) measures to reduce COVID spreading. Methods We analysed COVID-19 outbreaks in 12 NH using rRT-PCR for SARS-CoV-2. We estimated secondary attack risks (SARs) and identified cofactors associated with the proportion of infected residents. Results The SAR was below 5%, suggesting a high efficiency of IPC measures. Mask-wearing or establishment of COVID-19 zones for infected residents were associated with lower SAR. Conclusions Wearing masks and isolating potentially infected residents appear to limit SARS-CoV-2 spread in nursing homes.