Assessment of a novel, easy-to-implement, aerosolized H₂O₂ decontamination method for single-use filtering facepiece respirators in case of shortage

Abstract

The COVID-19 pandemic has affected the world and caused a supply shortage of personal protection equipment, especially filtering facepiece respirators (FFP). This has increased the risk of many healthcare workers contracting SARS-CoV-2. Various strategies have been assessed to tackle these supply issues. In critical shortage scenarios, reusing single-use-designed respirators may be required. Thus, an easily applicable and reliable FFP2 (or alike) respirator decontamination method, allowing safe re-use of FFP2 respirators by healthcare personnel, has been developed and is presented in this study. A potent and gentle aerosolized hydrogen peroxide (12% wt) method was applied over 4 hr to decontaminate various brands of FFP2 respirators within a small common room, followed by adequate aeration and storage overnight. The microbial efficacy was tested on unused respirator pieces using spores of Geobacillus stearothermophilus. Further, decontamination effectiveness was tested on used respirators after one 12-hr shift by swabbing before and after the decontamination. The effects of up to ten decontamination cycles on the respirators’ functionality were evaluated using material properties, the structural integrity of the respirators, and fit tests with subjects. The suggested H₂O₂ decontamination procedure was proven to be (a) sufficiently potent (no microbial recovery, total inactivation of biological indicators as well as spore inoculum on critical respirator surfaces), (b) gentle as no significant damage to the respirator structural integrity and acceptable fit factors were observed, and (c) safe as no H₂O₂ residue were detected after the defined aeration and storage. Thus, this easy-to-implement and scalable method could overcome another severe respirator shortage, providing enough flexibility to draft safe, effective, and logistically simple crisis plans. However, as highlighted in this study, due to the wealth of design and material used in different models and brands of respirators, the decontamination process should be validated for each FFP respirator model before its field implementation.

Keywords:

• FFP
• hydrogen peroxide
• KN95
• N95
• reprocessing
• reuse

Acknowledgments

G.R. and C.G. thank Thomas Friedrich and Reto Augsburger for their work in conducting the material tests. A.S, D.H., and E.W. thank Gerhard Eich for his general support and Daniel Röösli and Osmel Dominguez for their work in conducting the microbiological tests at Triemli City Hospital. M.N. thanks Claudina Tacchini for conducting the microbiological inoculation and Christopher Horne for text editing at SKAN AG.

Conflicts of interest

The authors have declared no conflicts of interest.

Data availability

The authors confirm that the data supporting the findings of this study are available within the article.