Globally countries are witnessing a steep surge in COVID-19 (SARS-CoV-2) cases. In contrast, protective equipment light PPE and N95 respirator productions are not enough to meet the demand.
Healthcare workers are reusing the onetime usable protective equipment again and again due to the shortage. Though there are various methods used to decontaminate the protective equipment but not all are 100% full proof. To be effective, decontamination must result in the sterilization of the N95 respirator without impairment of respirator filtration or user fit.
A recently published new research in mBio an open-access journal of the American Society for Microbiology defines an effective, standardized decontamination method for hospitals and health care centers facing N95 respirator shortages.
The researchers, from Beth Israel Deaconess Medical Center, Harvard University and Massachusetts General Hospital, have detailed a reproducible decontamination approach that all health care workers would be able to utilize.
“We identified an effective method of N95 decontamination by microwave-generated steam utilizing universally accessible materials. Our method resulted in almost complete sterilization after only 3 min of treatment and did not appear to affect the integrity of N95 filtration or fit with repeated treatment,” the researchers write.
Microwave-generated steam has verified to be an effective method of decontamination. In seeking a platform with widespread availability, it initially tested two protocols using common household items.
Both protocols involved the use of a 10-cm-diameter ceramic mug filled with 60 ml distilled water and covered with the mesh from a produce bag secured with a rubber band, on which the respirator was suspended directly above the generated steam.
The process examined the ability of both methods to sterilize N95 coupons (excised 1-cm2 3M 1860 N95 fabric squares) inoculated with 107 PFU of MS2 phage. The inoculation of 107 PFU represents a higher viral load than any viral droplet a health care provider is likely to encounter in the clinical setting (10).
After 1 min of microwave steam decontamination, it is seen that no significant difference in MS2 phage reduction between the two methods. It is important to note that both methods resulted in a greater than 4-log10 reduction in MS2 titer after only 1 min of microwave treatment.
The Ziploc bag, however, melted under this treatment and posed the risk of steam burns during retrieval of the N95 respirator. Noting equal efficacy, we proceeded with the open-container method of steam decontamination for all further work.
In summary, the research identified an effective method of N95 decontamination by microwave-generated steam utilizing universally accessible materials. The method resulted in almost complete sterilization after only 3 min of treatment and did not appear to affect the integrity of N95 filtration or fit with repeated treatment.