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

T. Hans Derr; Melissa A. James; Chad V. Kuny; Prem P. Kandel; Matthew D. Beckman; Kevin L. Hockett; Mark A. Bates; Moriah L Szpara

A demonstration study was conducted at the Pennsylvania State University at the Eva J. Pell Laboratory, to establish an effective N95 respirator decontamination protocol. This study focused on the ability of the Curis® decontamination system to effectively achieve viral and microbial sterilization of N95 respirators by aerosolized H2O2 (aHP), while preserving successful respirator fitting by medical staff after multiple cycles of decontamination. This study included multiple respirator facepiece types, representing those in wide use by local healthcare and research personnel. Successful decontamination of microbes was tested using stable, resistant spore-based bio-indicators (Geobacillus stearothermophilus), as well as by using multiple viral surrogates which represent the structure, characteristics, and environmental resistance of the SARS-CoV-2 pathogen. Virologic testing utilized sensitive plaque assays to detect the partial inactivation of viruses by drying onto respirator surfaces, and their subsequent decontamination by aHP. Fitness of respirators for reuse was assessed by qualitative and quantitative respirator fit testing on respirators subjected to multiple decontamination cycles. Real-time measurement and separate sample analyses were used to confirm acceptable aHP levels for decontamination, and the decomposition of aHP through drying prior to fit testing and reuse.