Misinformation About Face Masks
Since the beginning of the pandemic, there has been a raging — sometimes ill-informed — debate over the effectiveness of face masks as protection against SARS-CoV-2, the virus that causes COVID-19.
Multiple lines of evidence back the use of face masks to limit the spread of the coronavirus.
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 fool-proof, as no mask is thought to offer complete protection to the wearer or to others. For optimal performance, the Centers for Disease Control and Prevention recommends that people select masks that are well-fitting and multi-layered. For more, see our SciCheck story, “The Evolving Science of Face Masks and COVID-19.”
Initially, there was limited evidence to support broad masking policies for the general public, and the Centers for Disease Control and Prevention recommended masks only for those infected and medical providers treating them. On April 3, 2020, the CDC reversed course and recommended that everyone wear face coverings in public, citing new data that showed a “significant portion” of people infected with the coronavirus lack symptoms but can spread the virus to others.
Since then, a growing body of evidence supports the use of masks to slow the spread of COVID-19, as we reported in March.
Numerous lab studies, for example, show that high-quality, well-fitting masks can partially block exhaled respiratory droplets, which are thought to be the primary way the virus spreads, N95 respirators performed the best in preventing the spread of particles from a simulated cough — blocking 99% of the particles — while medical masks blocked 59% and a cloth mask blocked 51%. (See SciCheck’s “.”)
