Scalable in-hospital decontamination of N95 filtering face-piece respirator with a peracetic acid room disinfection system

Abstract

Background: Critical shortages of personal protective equipment especially N95 respirators during the COVID- 19 pandemic continues to be a source of concern. Novel methods of N95 filtering facepiece respirator decontamination that can be scaled-up for in-hospital use can help address this concern and keep HCWs safe. Methods: A multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≥6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency (FE). PAA and hydrogen peroxide off-gassing from treated masks were also assessed. Results: The PAA room HLDS was effective for disinfection of bacteriophage MS2 and G. stearothermophilus spores on respirators in a 2447 cubic feet room with aerosol deploy and dwell times of 16 and 32 minutes, respectively. The total cycle time was 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA and hydrogen peroxide from the treated masks at 20 and 60 minutes after the disinfection cycle respectively. Conclusion: The PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators during the COVID- 19 pandemic.

Fogging With Peracetic Acid in Schools and Kindergartens

“…In their study, Cutts et al demonstrate that dry fogging with PAA completely inactivated SARS-CoV-2 on test surfaces. They also suggested that with the ease of use, low cost, and overall effectiveness of a PAA, dry fogging should also be considered for decontamination in the prevention of COVID-19 (13). Another study demonstrated the effectiveness of PAA for disinfection of Geobacillus stearothermophilus (G. stearothermophilus) spores and bacteriophage MS2 on N95 respirators, proposing a PAA room disinfection system as a solution for decontamination of a great number of N95 respirators during the outbreak of COVID-19 (14).…”

Review of aerosolized hydrogen peroxide, vaporized hydrogen peroxide, and hydrogen peroxide gas plasma in the decontamination of filtering facepiece respirators

“…Using the Altapure AP-4 aHP with peracetic acid, John et al found that H2O2 had dissipated to 0.0 ppm within 60 minutes of off-gassing and the peracetic acid was undetectable within 20 minutes. 13 Unpublished data by Derr et al found that H2O2 was less than <0.5 ppm, within permitted levels, after treatment. However, many aHP solutions contain silver cations or peracetic acid, requiring additional studies to determine if any toxic residues or off-gassing post-decontamination could cause harm to the wearer (Derr, Unpublished Data).…”

“… 12 John et al found that with the Altapure AP-4 aHP system with peracetic acid (Altapure, Mequon, WI), both hydrophobicity and filtration efficiency were retained following 5 cycles of decontamination. 13 …”

“… 12 John et al found a 6 log reduction of G. stearothermophilus spores and bacteriophage MS2 using the Altapure system. 13 …”

Influence of Spray Nozzle Operating Parameters on the Fogging Process Implemented to Prevent the Spread of SARS-CoV-2 Virus

“…The research [6,7] also analyzed the effect of fogging on various surfaces (walls, floors, components of subway cars), and in work [3], a largescale application of fumigation in the urban space affecting spaces in the environment was proposed. The literature also includes many items describing the use of fogging for disinfecting medical masks and protective clothing in fumigation rooms or lodging facilities [12][13][14][15][16]. A noteworthy publication is the study by Villermaux [17], which is a very detailed analysis of atomization mechanisms.…”