Update The use of masks by asymptomatic people to reduce transmission of COVID-19

Abstract

This Evidence Snapshot is a July 2020 updated rapid review of knowledge about the use of masks by asymptomatic people to reduce transmission of COVID-19, the original review having been completed in April 2020. The updated review found that, while the evidence was limited and of low certainty, wearing masks in community settings is likely to reduce transmission of COVID-19. Some peer-reviewed studies included other protective measures in their scope, and thirteen of the twenty-eight recommended using masks in combination with these other measures. Where supply of masks is limited, higher risk individuals or residential areas with high transmission rates should be prioritised. A total of fifty-one articles were reviewed: 28 peer reviewed studies and 23 commentary articles and agency reports, with 31 of these articles being new in the updated report.