Masks offer the greatest protection indoors but other public-health measures matter, too --New study .

When are masks most useful? COVID cases offer... Nature - Masks offer the greatest protection indoors and during long exposures to people infected with the coronavirus — but other public-health measures matter, too. Remmel, Ariana nature

An analysis of hundreds of COVID-19 cases suggests that face masks are most protective in specific circumstances, such as exposure to a person with COVID-19 that lasts for more than three hours or that takes place indoors¹.

The study shows that several of the measures that are collectively known as non-pharmaceutical interventions — such as physical distancing, keeping interactions outdoors and wearing masks — “are in fact helpful” for preventing SARS-CoV-2 transmission, says study co-author Joseph Lewnard, an epidemiologist at the University of California, Berkeley. Previous studies^2,3 provided evidence that masking helps to protect against infection, but the latest work shows that it is beneficial even when other measures, such as distancing, aren’t in use. ...