Sickbert-Bennett EE, Samet JM, Clapp PW, et al. - This study was undertaken to evaluate fitted filtration efficiencies (FFEs) for face mask alternatives used during the COVID-19 pandemic. Researchers applied 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 for this quality-improvement study conducted between April and June 2020. Expired N95 respirators with intact elastic straps and respirators subjected to ethylene oxide and hydrogen peroxide sterilization had unchanged FFE (> 95%) out of the 29 different fitted face mask alternatives tested on 1 man and 1 woman. During the COVID-19 pandemic, this quality-improvement study assessing 29 face mask alternatives for use by clinicians interacting with patients found that expired N95 respirators and sterilized, used N95 respirators can be used when new N95 respirators are not available. It was reported that other alternatives may provide less effective filtration.