Assessing Mask Integrity and Fit of N95 Masks after 5 Cycles of Decontamination and Reuse in a Simulated Clinical Setting

Aim: To evaluate the effect of decontamination and reuse on N95 masks. Background(s): The coronavirus disease (COVID-19) pandemic has strained the global availability of masks. Such shortage represents a threat to healthcare workers (HCWs). Mask reprocessing and reuse may alleviate the shortage. Many laboratory studies have proven the effectiveness and feasibility of decontaminating N95 masks. However, very few had HCWs wearing them between cycles of decontamination. Our study evaluated mask integrity (assessed by qualitative mask fitting [QMF], as well as technical measures like bacterial filtration efficacy [BFE]) through five cycles of decontamination using four different modalities - steam, moist heat (MH), UV-C irradiation (UVCI), and hydrogen peroxide vaporization (HPV). Method(s): Each study cycle involved a HCW wearing a N95 mask for two hours, followed by the assigned decontamination process, and then a QMF. This was repeated for a maximum of 5 cycles, as long as the wearer passed QMF. 40 HCWs were recruited for each of the four decontamination modalities. The technical measures of mask integrity assessed were: BFE, Particulate Filtration Efficiency (PFE), Pressure Drop and Splash Resistance. Result(s): 60.6% (HPV) to 77.5% (MH) of the masks passed five cycles of wear and decontamination, as assessed by the wearers passing QMF all five times. MH-decontaminated masks retained all technical measures of integrity through all 5 cycles. HPV reduced masks' BFE after the fourth cycle while UVCI tended to increase the Pressure Drop. Conclusion(s): The results suggest that MH is a promising method for decontaminating N95 masks without compromising fit and integrity. [Figure presented] [Table presented]Copyright © 2023 Southern Society for Clinical Investigation.

N95 respirator decontamination: a study in reusability.

The coronavirus disease 2019 (COVID-19) pandemic had caused a severe depletion of the worldwide supply of N95 respirators. The development of methods to effectively decontaminate N95 respirators while maintaining their integrity is crucial for respirator regeneration and reuse. In this study, we systematically evaluated five respirator decontamination methods using vaporized hydrogen peroxide (VHP) or ultraviolet (254 nm wavelength, UVC) radiation. Through testing the bioburden, filtration, fluid resistance, and fit (shape) of the decontaminated respirators, we found that the decontamination methods using BioQuell VHP, custom VHP container, Steris VHP, and Sterrad VHP effectively inactivated Cardiovirus (3-log10 reduction) and bacteria (6-log10 reduction) without compromising the respirator integrity after 2-15 cycles. Hope UVC system was capable of inactivating Cardiovirus (3-log10 reduction) but exhibited relatively poorer bactericidal activity. These methods are capable of decontaminating 10-1000 respirators per batch with varied decontamination times (10-200 min). Our findings show that N95 respirators treated by the previously mentioned decontamination methods are safe and effective for reuse by industry, laboratories, and hospitals.