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

Five models of respirator are presently utilized in this study, to gain insight into which models best withstand aHP and successfully complete fit-testing thereafter. Testing included more than 150 respirator fit-tests (see below for details). Wherever possible, respirators already subjected to quantitative fit-testing were redirected to virologic testing in future cycles, thus conserving overall respirator consumption for the study. Successful chemical disinfection by H2O2 was confirmed using Verify® Chemical Indicators (H2O2) placed on room surfaces, behind or beneath portable equipment in the decontamination room, and on the metal racks holding the respirators. Commercial spore-based biological indicators (Geobacillus stearothermophilus) were likewise placed on or between respirator facepieces on metal racks, as well as behind or beneath portable equipment in the decontamination room. These biological indicators confirmed complete spore killing by aHP. Respirator surface concentrations of residual H2O2 were monitored via a portable monitor. These ranged from non-detectable to <0.5 ppm aHP, prior to transfer for fit-testing or sealing for virologic testing. We found that respirator movement to a "finishing room" was useful to support more rapid H2O2 dissipation from respirators. While this study did not involve respirator reuse in actual hospital settings, we simulated conditions of reuse by handling respirators and stretching elastic between sequential decontamination cycles, in addition to wearing respirators during fit-testing as described below.