Aerosolized Hydrogen Peroxide Decontamination of N95 Respirators, with Fit-Testing and Virologic Confirmation of Suitability for Re-Use During the COVID-19 Pandemic

Abstract

AbstractIn response to the current demand for N95 respirators by healthcare workers responding to the COVID-19 pandemic, we evaluated decontamination of N95 respirators using a low concentration aerosolized hydrogen peroxide (aHP) system. This system dispenses a consistent atomized spray of micron-sized, low concentration, hydrogen peroxide (H2O2) particles over a treatment cycle. Multiple N95 respirator models were subjected to ten or more cycles of respirator decontamination, and masks were periodically assessed for qualitative and quantitative fit testing to verify respirator integrity. In parallel, we assessed the ability of aHP treatment to inactivate multiple viruses absorbed onto masks, including phi6 bacteriophage, HSV-1, CVB3, and SARS-CoV-2. Given that SARS-CoV-2 is transmitted via expired respiratory droplets and aerosols, it is critical to address respirator safety for reuse. This study provided experimental validation of a suitable aHP treatment process that decontaminates the respirators while maintaining N95 function. After ten rounds of aHP treatment, respirators passed N95 filtration efficiency testing. Virus inactivation by aHP was comparable to the sterilization of commercial spore-based biological indicators. These data demonstrate that the aHP process is effective, on the basis of zero failure rate on fit-testing of respirators, effective decontamination of multiple virus species including SARS-CoV-2, successful sterilization of bacterial spores, and filtration efficiency maintained at or greater than 95%. Collectively, these studies support the use of specific aHP decontamination protocol that permits safe reuse of N95 respirators by healthcare providers.ImportanceThe ongoing COVID-19 pandemic has led to unprecedented pressure on healthcare and research facilities to provide adequate personal protective equipment. Given that the current pandemic is caused by a respiratory viral pathogen, the availability of highly protective respirator facepieces is critical to limit inhalation of this virus. While respirator facepieces were designed for single-use and disposal, the pandemic has increased overall demand for N95 respirators, and corresponding manufacturing and supply chain limitations have necessitated the safe reuse of respirators when necessary. The biosafety level 3 (BSL3) facility used in this study regularly utilizes aerosolized hydrogen peroxide (aHP) to decontaminate equipment and spaces. We repurposed this technology for N95 respirator decontamination during the COVID-19 pandemic. Results from virus inactivation, biological indicators, respirator fit testing, and filtration efficiency testing all indicated that the process was effective at rendering N95 respirator safe for reuse.