This talk goes over the importance of face masks as a pillar of COVID-19 pandemic control. First, we review the epidemiologic evidence for how face masks reduce COVID-19 transmission from studies in the United States since the beginning of the pandemic.  We then discuss an emerging hypothesis that viral inoculum or dose is related to severity of disease so that face masks may also increase the proportion of asymptomatic infection (if infection occurs) by reducing viral dose. Finally this talk discusses the physical science properties of masks and makes recommendations for basic and maximal protection masks for the public.

Learning Objectives:

1. To review the epidemiologic data on how face masks reduce COVID-19 transmission

2. To explore the hypothesis that reducing the viral inoculum (via face masks) will lead to less severe disease if infected

3. To review the type of face masks most protective for the public