Which masks protect against delta COVID-19 variant?
CDC mask guidance shift sparks new debate
The U.S. Centers for Disease Control and Prevention on Tuesday announced a revision to its guidance on face coverings, recommending everyone wear masks indoors in high-risk areas and that masks also be worn inside K-12 schools. That has sparked impassioned responses from business owners, elected leaders, school officials and parents of students attending those schools this fall.
The CDC has advised fully vaccinated Americans to resume wearing masks while indoors in certain public settings amid a rise in COVID-19 cases largely due to the delta variant. The delta variant, which was first identified in India, is considered highly transmissible and now accounts for upwards of 83% of cases in the U.S.
CDC director Dr. Rochelle Walensky recently began referring to the surge in cases as a pandemic among the unvaccinated, but for those returning to wearing masks a former FDA official suggested certain types of face coverings may offer better protection against the infectious variant.
"It’s not more airborne and it’s not more likely to be permeable to a mask," Dr. Scott Gottlieb, former FDA commissioner, told CBS’s "Face the Nation." "The quality of the mask does matter. So if you can get your hands on a KN95 or N95 mask, that’s going to afford you a lot more protection."
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Both masks are designed to filter 95% of particles entering the mask. KN95 masks are manufactured in China.
Currently, the CDC recommends that N95 respirators be prioritized for protection against COVID-19 in health care settings. The agency recommends essential workers and workers who routinely wore respirators before the pandemic continue wearing N95 respirators, and that as they become available they can be worn in non-health care settings.
The agency also warns that about 60% of KN95 masks in the U.S. are counterfeit, and do not meet National Institute for Occupational Safety and Health (NIOSH) standards.
Gottlieb said that while there were shortages early in the pandemic, masks have become more widely available so he would encourage others to "look at the quality of their mask."
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Still, the FDA warns that the "optimal way to prevent airborne transmission is to use a combination of interventions from across the hierarchy of controls, not just PPE alone."
The CDC also has not issued guidance that indicates certain masks may offer better protection against the variant, and instead suggests choosing a mask with two or more layers of washable, breathable fabric that completely cover the nose and mouth. Masks should fit snugly against the side of the face without gaps, and have a nose wire to prevent air from leaking out of the top.