Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES International Journal of Epidemiology 1788-1794 COVID-19 aged-care facilities mask wearing generalized linear mixed models secondary-attack risk FRANCE HERAULT 2021 fdi:010084235 ENG International Journal of Epidemiology 0300-5771 ISI:000744086800012 6 10.1093/ije/dyab121 https://www.documentation.ird.fr/hor/fdi:010084235 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2022-03/010084235.pdf 50 Horizon (IRD) Background: The COVID-19 epidemic has spread rapidly within aged-care facilities (ACFs), where the infection-fatality ratio is high. It is therefore urgent to evaluate the efficiency of infection prevention and control (IPC) measures in reducing SARS-CoV-2 transmission. Methods: We analysed the COVID-19 outbreaks that took place between March and May 2020 in 12 ACFs using reverse transcription-polymerase chain reaction (RT-PCR) and serological tests for SARS-CoV-2 infection. Using maximum-likelihood approaches and generalized linear mixed models, we analysed the proportion of infected residents in ACFs and identified covariates associated with the proportion of infected residents. Results: The secondary-attack risk was estimated at 4.1%, suggesting a high efficiency of the IPC measures implemented in the region. Mask wearing and the establishment of COVID-19 zones for infected residents were the two main covariates associated with lower secondary-attack risks. Conclusions: Wearing masks and isolating potentially infected residents appear to be associated with a more limited spread of SARS-CoV-2 in ACFs. 050 ; 052 ; 020 UR224