Thread by @DocJeffD

Significant update from CDC states mask use protects not only others but the wearer: "Masks also help reduce inhalation of these droplets by the wearer (“filtration for personal protection”)." 1/n

Coronavirus Disease 2019 (COVID-19) cdc.gov/coronavirus/20… via @CDCgov

"The community benefit of masking for SARS-CoV-2 control is due to the combination of these effects; individual prevention benefit increases with increasing numbers of people using masks consistently and correctly." 2/2

Masks should be well made & fit well (snug w/out gaps) "Multiple layers of cloth with higher thread counts have demonstrated superior performance compared to single layers of cloth with lower thread counts, in some cases filtering nearly 50% of fine particles less than 1 micron."

IMPORTANT CAVEAT! Masks do not complete/reliable protection & MUST be part of a layered strategy with limiting number, duration & proximity of contacts with others, avoiding poorly ventilated spaces/improving ventilation, hand hygiene, etc.