Cloth masks provide inferior protection vs. medical masks, suggests evidence review



Not considered PPE

According to routine infection prevention and control recommendations for health care personnel from the Centers for Disease Control and Prevention, face masks – often referred to as surgical masks or procedure masks – should be worn by workers “at all times while they are in the healthcare facility, including in break rooms or other spaces where they might encounter coworkers.”

Unlike cloth masks, face masks offer “protection for the wearer against exposure to splashes and sprays of infectious material from others,” as well as source control, the agency says. Health care personnel “should remove their respirator or face mask, perform hand hygiene, and put on their cloth mask when leaving the facility at the end of their shift,” according to the CDC.

“Cloth masks are NOT PPE and should not be worn for the care of patients with suspected or confirmed COVID-19 or other situations where use of a respirator or face mask is recommended,” the agency notes.

When respirators or face masks are unavailable, health care personnel “might use cloth masks as a last resort for care of patients with suspected or confirmed diagnosis for which face mask or respirator use is normally recommended,” according to CDC guidance.

In that scenario, cloth masks “should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face,” the CDC says.

Limited data for comparisons

A Dec. 29, 2020, update in Annals of Internal Medicine about masks for prevention of respiratory virus infections highlighted two recent studies in the United States that reported on mask use in health care settings. A study of more than 16,000 health care workers and first responders found that those who used an N95 or surgical mask all of the time were less likely to have SARS-CoV-2 antibodies, compared with workers who did not wear masks all the time. The adjusted odds ratio with consistent N95 use was 0.83, and the aOR with consistent surgical mask use was 0.86.

In the second study, which included more than 20,000 asymptomatic health care workers, risk for infection was reduced with any mask use versus no mask use (OR, 0.58). An N95 mask was associated with decreased risk versus a surgical mask (OR, 0.76). The studies had methodological limitations, however, and “evidence for various comparisons about mask use in health care settings and risk for SARS-CoV-2 remains insufficient,” the authors of the update wrote.

The Annals of Family Medicine review authors had no relevant disclosures. Dr. Chughtai has tested filtration of 3M masks and worked with CleanSpace Technology to research fit testing of respirators, and the 2015 randomized trial was funded by an Australian Research Council Linkage Grant with 3M as a partner on the grant. The Dec. 29, 2020, update was of a review that originally was supported by grants from the Agency for Healthcare Research Quality.

SOURCE: Daoud AK et al. Ann Fam Med. 2020 Jan 11. doi: 10.1370/afm.2640.


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