Lab tests, for example, show that masks can partially block exhaled respiratory droplets, which are thought to be the primary way the virus spreads. Analyses of people who came into contact with those with COVID-19 have also found mask-wearing to be associated with a reduced risk of contracting the virus. Numerous studies similarly document an association between self-reported mask wearing and control of the virus in a community or the implementation of a mask mandate and a subsequent decline in COVID-19 cases.
While each of these study types has its limitations, collectively, most experts agree that masks are likely to reduce transmission of the coronavirus and should be used by members of the public when around other people. Some research also indicates face masks can protect the wearer as well.
Masks, however, should not be viewed as foolproof, as no mask is thought to offer complete protection to the wearer or to others. The Centers for Disease Control and Prevention recommends that people wear the most protective mask that fits well and can be worn consistently. Loosely woven cloth masks are the least protective. Layered, tightly woven cloth masks offer more protection, while well-fitting surgical masks and KN95 respirators provide even more protection and N95 respirators are the most protective. For more, see our SciCheck story, “The Evolving Science of Face Masks and COVID-19.”