The N95 respirators recommended by the U.S. Centers for Disease Control as the ideal protection method from COVID-19 are single-use devices but personal protective equipment shortages have necessitated the need for reuse. A new decontamination method has been developed based on microwave-generated steam to enable sterilization and reuse of this essential equipment.

The technique devised by researchers from Beth Israel Deaconess Medical Center, Harvard University and A glass container was filled with 60 ml of distilled water, covered with mesh from a produce bag and secured with a rubber band. Source: Katelyn E. Zulauf et al.Massachusetts General Hospital uses materials accessible to healthcare workers, including glass containers, mesh from commercial produce bags, a rubber band, and a 1,100 W commercially available microwave. When tested against the Escherichia coli MS2 bacteriophage as a surrogate for SARS-CoV-2 contamination, the sterilization scheme resulted in a 99.99% reduction in plaque-forming units after three minutes of processing.

A glass container with an opening sufficient to expose the entire N95 respirator to a vertical column of generated steam is placed in the microwave. Mesh from a produce bag is secured with a rubber band over the top of the container filled with 60 ml of distilled water. The researchers then evaluated the efficacy of the sterilization process in one-minute increments.

The sterilization procedure described in mBio did not appear to impact the integrity of N95 filtration or fit with repeated treatments and can offer a means of effective decontamination and reuse of N95 respirators by frontline providers.