The effectiveness of wearing masks to protect from airborne germs and viruses has been studied and proven for more than a century (that’s why masks are worn in surgery).
And, since the COVID virus was identified, scientists around the world have been studying:
• Do masks protect specifically against COVID?
• If yes, what kinds of masks work best?
The CDC reviewed 90 studies and the medical journal, The Lancet, reviewed 172 studies in which they found that masking significantly lowered the risk of COVID infection – especially when the mask was an N95.
N95 is a designation given by the National Institute for Occupational Safety and Health (NIOSH). They test masks to ensure the masks can block the COVID virus (or any other very small particle) at least 95% of the time at “a high work rate.”
Because NIOSH tests use particles that are much smaller than virus-carrying emissions, at much higher flow rates than normally seen in community settings, N95 masks have consistently proven to be helpful in preventing COVID transmission.
The American Conference of Governmental Industrial Hygienists (ACGIH) released a study comparing the time it takes for COVID-19 to transmit through different kinds of masks when standing 6 feet apart.
With all this, it should be noted that masks alone are not the answer. They are part of the layers of protection used to prevent the spread of COVID. Keeping up to date with vaccines and boosters, staying home when you’re sick, wearing masks in high-risk situations like in crowds, and social distancing when around people whose vaccination status you don’t know, all work together to help protect from COVID (and other nasty viruses, too).
Sources: https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/masking-science-sars-cov2.html (CDC)
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext (The Lancet)