Abstract
We are pleased to introduce this special themed issue of Applied Biosafety that focuses on various methods used to decontaminate or reduce bioburden on respirators and how respirators and filters can be quantitatively tested to ensure that efficacy has not been compromised. As respirators remain in short supply for healthcare workers and those conducting research with infectious agents during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, decontamination and reuse of respirators have become a necessary and familiar practice in healthcare and research settings. Since the recent rapid publication of articles on SARS-CoV-2 has created difficulty for many biosafety professionals to keep pace with the literature, this special themed issue features four review articles by the N95DECON Consortium that consolidate information regarding several technologies being used or considered in decontaminating or reducing bioburden on respirators. For example, Rempel et al. summarized the decontamination efficacy and effects N95 fit and filter efficiency after decontamination using various hydrogen peroxide generating systems and different cycles. Grist et al. reviewed the use of ultraviolet-C (UV-C) irradiation in decontaminating N95 respirators and highlighted whether UV-C treatment resulted in respirator strap or filter material damage. On March 31, 2020, the U.S. Centers for Disease Control and Prevention (CDC) identified humid heat as a promising method for the treatment of N95 respirators under crisis conditions. Therefore, Anderegg et al. conducted a literature review on heat-based methods for decontamination of N95 filtering facepiece respirators (FFRs) contaminated either with SARS-CoV-2 or with viral analogues and identified parameters that were more successful in reducing bioburden while maintaining fit and filtration efficiency so respirators could be safely reused. Smullin et al. reviewed the literature to determine whether storage of FFRs at room temperature could provide a reliable and repeatable means of reducing bioburden to an acceptable level for FFR reuse. Variations in the materials and environmental conditions in different studies made it impossible to extrapolate with a strong degree of certainty a precise 3-log decay time for each FFR type, demonstrating the need for controlled studies on this topic.
Whether in the laboratory or healthcare setting, testing respirators and filter media efficiency is essential to ensure personnel are protected when working in environments where pathogens that pose a risk of infection through the respiratory route exist. As part of a BSL-4 protective suit management program, Fey et al. validated a method for testing filter integrity and filter loading and compared several brands of filters over time to determine filter lifespan. In the healthcare setting, as respirators were in short supply during the SARS-CoV-2 pandemic, many new models of filtering masks entered the market. Little was known about the efficacy of these new products since independent third-party testing was not routinely conducted. Örebrand et al. measured particle penetration through the filter media of 86 models of masks using sodium chloride particles according to the EN149 §7.9.2 standard for particle penetration and found large variation in filtration effectiveness between filtering masks, with some providing very little protection. These test data are valuable and inform healthcare providers and other groups procuring respiratory protective devices.
The articles in this issue of Applied Biosafety provide timely applied information that can be used by individuals and institutions for decision making during the COVID-19 pandemic and in the future. We are happy to share that articles published regarding SARS-CoV-2 have been made available online at no charge until December 31, 2021, by our publisher Mary Ann Liebert, Inc., at (https://home.liebertpub.com/spcoll/coverage-of-covid-19-and-the-pandemic/1130).