Assessment of N95 Respirator Decontamination and Re-Use for SARS-Cov-2

Fischer RJ, Morris DJ, Doremalen N, et al. medRxiv. April 15, 2020. [CrossRef]

A shortage of N95 masks designed for single has forced many to reuse masks and attempt to sterilize the masks between uses. In a not as yet peer-reviewed preprint, the authors analyzed four different decontamination methods – UV radiation (260 – 285 nm), 70ºC heat, 70% ethanol and vaporized hydrogen peroxide (VHP) – for their ability to reduce contamination with infectious SARS-CoV-2 (COVID-19) and their effect on N95 respirator function. Vaporized hydrogen peroxide, ethanol and heat yielded extremely rapid inactivation but UV inactivated SARS-CoV-2 more slowly. Quantitative fit tests showed that the filtration performance of the N95 respirator was not markedly reduced after a single decontamination for any of the four decontamination methods. Subsequent rounds of decontamination caused sharp drops in filtration performance of the ethanol-treated masks, and to a slightly lesser degree, the heat-treated masks. The VHP- and UV-treated masks retained comparable filtration performance to the control group after two rounds of decontamination, and maintained acceptable performance after three rounds. The authors recommend VHP for decontamination based on their data that the VHP treatment exhibited the best combination of rapid inactivation of SARS-CoV-2 and preservation of N95 respirator integrity.