In pandemic situations such as COVID-19, shortages of proper protective equipment are common. One solution may be to decontaminate equipment such as facemasks for reuse.
The aim of this review was to collect and synthesize existing information on decontamination of N95 filtering facepiece respirators (FFRs) using microwave and heat-based treatments, with special attention to impact on mask function (aerosol penetration, airflow resistance) and fit.
A systematic review (PROSPERO ID pending) of literature available on Medline, Embase, Global Health, JISRP and JEFF was conducted. Records were screened independently by two reviewers, and data was extracted and analyzed from studies that reported on the effects of microwave-or heat-based decontamination on N95 FFR performance and/or microbial load.
All interventions successfully destroyed viral/bacterial contaminants. Other than autoclaving, which significantly increased aerosol penetration, moist and dry microwave and heat conditions did not significantly impact functional parameters or fit. However, several conditions caused physical damage to at least one N95 model.
Microwave irradiation and heat provides safe and effective decontamination options for N95 FFR reuse during critical shortages. However, autoclaving masks is not recommended by the evidence in this review. Any mask disinfected using these methods should be inspected for physical degradation before reuse.