Respirator Masks 48% More Effective Than Cloth Masks, Study Finds

Topline

N95 and KN95 respirator masks reduce the odds of testing positive for Covid-19 by 83% compared to 66% for surgical masks and 56% for cloth masks, according to a real-world study published Friday by the U.S. Centers for Disease Control and Prevention, reinforcing efforts to phase out cloth masks in favor of more effective face coverings.

An N95 respirator mask.

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Key Facts

Researchers affiliated with the University of California at Berkeley and the California Department of Public Health determined that any kind of mask offers significant protection against Covid and that it’s “most important” to wear a properly fitting mask that can be used consistently.

These findings reinforce the need to improve access to high-quality masks and to ensure access is not a barrier to use, the researchers said.

The study ran from February 18 to December 1 and included 3,039 California residents.

Key Background

Previous lab tests have suggested that community-level masking requirements reduce Covid rates and that masks help prevent wearers either from contracting the disease or from passing it on to others. These findings reinforce a 2020 real-world study carried out on the aircraft carrier USS Theodore Roosevelt, where crew members who wore masks during a Covid outbreak had a 55.8% chance of being infected and those who did not wear masks had a roughly 80% chance of being infected. However, data on the efficacy of cloth masks has proven inconsistent—while the CDC found cloth masks 56% effective, a study of Bangladeshi villages found cloth masks only 5% effective, according to Smithsonian magazine. Such findings have prompted a shift in messaging toward promoting surgical and respirator masks. During the spread of the highly transmissible omicron variant, which now accounts for 99.9% of cases in the U.S., the School District of Philadelphia, Cornell University, the University of Arizona, the University of Southern California and other schools announced they would require students to wear surgical or respirator masks rather than cloth masks. Some airlines, including Air France, Lufthansa and Swiss International Air Lines, have also banned cloth masks in favor of more effective face coverings.

Big Number

400 million. That’s how many N95 masks the Biden Administration has pledged to provide free to the public.

Tangent

N95 and KN95 masks are theoretically similar in terms of filtration, but are certified by different organizations. N95 masks are certified by the U.S. National Institute for Occupational Safety and Health while the more widely available KN95 masks are manufactured in China to meet national standards. NIOSH found that about 60% of KN95 masks don’t work as well as intended.

Contra

Though respirator masks are generally more effective than cloth masks, many people choose to wear cloth masks because they are more comfortable, researchers at the University of Virginia concluded. Tests commissioned by the New York Times found that cloth masks with filter inserts blocked from 94% to 99% of the smallest particles tested, performance similar to N95 and KN95 respirator masks.