Reusing N95 Respirators at Weekly Intervals During the COVID-19 Pandemic.

Objectives A surge in the demand for N95 filtering facepiece respirators (N95 respirators) due to the worldwide spread of coronavirus disease 2019 (COVID-19) has resulted in a global shortage of N95 respirators. This study was performed to evaluate the clinical validation of reusing N95 respirators following stringent fit test protocols. Methods After passing the first fit test, we prospectively enrolled healthcare workers who used N95 respirators for two hours per shift (duckbill-shaped HPR-R/HPR-S, dome-shaped Hi-Luck 350, and three-panel flat-fold respirators 9211) in settings such as bronchoscopy or respiratory specimen sampling. These procedures were repeated for up to three weeks, with the fit test performed every week. At each timing of the fit test, we used a fit-testing system for quantitatively evaluating particle leakage. Results A total of 41 participants were enrolled, including 24 doctors and 17 nurses, of whom 25 were women. The pass rate of successful reuse over three observational weeks using four fit tests was 85.4%, which was comparable among the three types of N95 respirators. Six (14.6%) participants failed the fit test, while no participants dropped out of protocol due to either N95 respirator damage or contamination. Among the six dropped out participants, four reused the duckbill-shaped type and two reused the three-panel flat-fold type. All participants using the cup-shaped type mask successfully completed the protocol. However, the passing rate of this study was not statistically different among the three types of N95 respirators. Conclusion This study shows that N95 respirators can be safely reused for a short period irrespective of their type, as quantitatively assessed by fit tests.