Procuring respiratory protection for clinicians and other health care workers has become a major challenge of the coronavirus disease 2019 (COVID-19) pandemic and has resulted in nonstandard practices such as the use of expired respirators and various decontamination processes to prolong the useful life of respirators in health care settings. In addition, imported, non-National Institute for Occupational Safety and Health (NIOSH)-approved respirators have been donated or acquired by hospitals as a potential replacement for limited NIOSH-approved N95 respirators. OBJECTIVE To assess fitted filtration efficiencies (FFEs) for face mask alternatives used during the COVID-19 pandemic. DESIGN, SETTING, AND PARTICIPANTS For this quality-improvement study conducted between April and June 2020, we used the Occupational Safety and Health Administration's Quantitative Fit Testing Protocol for Filtering Facepiece Respirators in a laboratory atmosphere supplemented with sodium chloride particles to assess the FFEs of a variety of respirators worn by a male volunteer and female volunteer. MAIN OUTCOMES AND MEASURES The FFEs of respirators commonly worn by clinicians and other health care workers and available respirator alternatives during the COVID-19 pandemic. RESULTS Of the 29 different fitted face mask alternatives tested on 1 man and 1 woman, expired N95 respirators with intact elastic straps and respirators subjected to ethylene oxide and hydrogen peroxide sterilization had unchanged FFE (>95%). The performance of N95 respirators in the wrong size had slightly decreased performance (90%-95% FFE). All of the respirators not listed as approved in this evaluation (n = 6) failed to achieve 95% FFE. Neither of the 2 imported respirators authorized for use by the Centers for Disease Control and Prevention that were not NIOSH-approved tested in this study achieved 95% FFE, and the more effective of the 2 functioned at approximately 80% FFE. Surgical and procedural face masks had filtering performance that was lower relative to that of N95 respirators (98.5% overall FFE), with procedural face masks secured with elastic ear loops showing the lowest efficiency (38.1% overall FFE). CONCLUSIONS AND RELEVANCE This quality-improvement study evaluating 29 face mask alternatives for use by clinicians interacting with patients during the COVID-19 pandemic found that expired N95 respirators and sterilized, used N95 respirators can be used when new N95 respirators are not available. Other alternatives may provide less effective filtration.

Background Globally, a large percentage of men keep a beard at least occasionally. Workplace regulations prohibit beards with N95 respirators, but there is little information on the effect of beards with face masks worn by the public for protection against SARS-CoV-2. Methods and findings We examined the fitted filtration efficiency (FFE) of five commonly worn protective face masks as a function of beard length following the US Occupational Safety and Health Administration Quantitative Fit Test: N95 (respirator), KF94 and KN95, surgical/procedure, and cloth masks. A comparison using N95 respirators was carried out in shaven and bearded men. A detailed examination was conducted for beard lengths between 0 and 10 mm (0.5 mm increments). The effect of an exercise band covering the beard on FFE was also tested. Although N95 respirators showed considerable variability among bearded men, they had the highest FFE for beard lengths up to 10 mm. KF94 and KN95 masks lost up to 40% of their FFE. Procedure and cotton masks had poor performance even on bare skin (10–30% FFE) that did not change appreciably with beard length. Marked performance improvements were observed with an exercise band worn over the beard. Conclusions Though variable, N95 respirators offer the best respiratory protection for bearded men. While KF94 and KN95 FFE is compromised considerably by increasing beard length, they proved better options than procedure and cotton face masks. A simple exercise band improves FFE for face masks commonly used by bearded men during the COVID-19 pandemic.

Although global vaccination efforts against SARS-CoV-2 are underway, the public is urged to continue using face masks as a primary intervention to control transmission. 1 Recently, US public health officials have also encouraged doubling masks as a strategy to counter elevated transmission associated with infectious SARS-CoV-2 variants. 2 US Centers for Disease Control and Prevention investigators reported that doubling masks increased effectiveness, but their assessment was limited in type and combinations of masks tested, as well as by the use of head forms rather than humans. To address these limitations, this study compared the fitted filtration efficiency (FFE) 3,4 of commonly available masks worn singly, doubled, or in combinations.

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