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Exposing contaminated N95 respirators to vaporized hydrogen peroxide (VHP) or ultraviolet (UV) light appears to get rid of the SARS-CoV-2 virus from the material and protect the integrity of the masks’ fit for up to 3 uses, a National Institutes of Health (NIH) study reveals.
Dry heat (70 ° C) was likewise found to get rid of the virus on masks however worked for 2 uses instead of three.
Robert Fischer, PhD, with the National Institute of Allergy and Infectious Illness in Hamilton, Montana, and coworkers published the findings on a preprint server on April 15. The paper has not yet been peer reviewed.
4 Approaches Evaluated
Fischer and associates compared four methods for decontaminating the masks, which are designed for one-time use: UV radiation (260– 285 nm); 70 ° C dry heat; 70% ethanol spray; and VHP.
For each technique, the researchers compared the rate at which SARS-CoV-2 is suspended on N95 filter material to that on stainless steel.
All 4 techniques got rid of noticeable SARS-CoV-2 infection from the fabric test samples, though the time required for decontamination differed. VHP was the quickest, requiring 10 minutes. Dry heat and UV light each needed roughly 60 minutes. Ethanol required an intermediate quantity of time.
To check durability over three usages, the researchers dealt with undamaged, tidy masks with the exact same decontamination method and examined function through quantitative fit screening.
Volunteers from the Rocky Mountain laboratory wore the masks for 2 hours to test fit and seal.
The researchers found that masks that had been decontaminated with ethanol spray did not operate efficiently after decontamination, and they did not recommend use of that technique.
By contrast, masks decontaminated with UV and VHP might be consumed to three times and function properly. Masks decontaminated with dry heat might be used two times prior to function decreased.
“Our results show that N95 respirators can be decontaminated and re-used in times of shortage for up to three times for UV and HPV, and as much as 2 times for dry heat,” the authors compose. “However, utmost care ought to be provided to guarantee the proper performance of the N95 respirator after each decontamination utilizing easily available qualitative fit screening tools and to make sure that treatments are brought out for sufficient time to accomplish desired risk-reduction.”
Reassurance for Clinicians
The outcomes will reassure clinicians, a number of whom are already using these decontamination techniques, Ravina Kullar, PharmD, Miles Per Hour, a contagious illness expert with the Transmittable Diseases Society of America, informed Medscape Medical News.
Kullar, who is likewise an accessory professor at the David Geffen School of Medicine of the University of California, Los Angeles, said the most extensively used approaches have been UV light and VPH.
UV light has actually been used for many years to decontaminate spaces, she said. She also stated that so far, materials of hydrogen peroxide are sufficient.
A drawback of the research study, Kullar said, is that it tested the masks for only 2 hours, whereas in scientific practice, they are being worn for much longer periods.
After the study is peer examined, the Centers for Disease Control and Prevention (CDC) might update its recommendations, she said.
Far, she noted, the CDC has not approved any method for decontaminating masks, “but it has said that it does not object to using these sterilizers, disinfectants, devices, and air purifiers for efficiently killing this infection.”
Safe, multiple usage of the masks is important in the COVID-19 crisis, she said.
“We have to look at other systems to keep these N95 respirators in use when there’s such a lack,” she said.
Stability of the fit was a crucial consider the study.
“All health care workers need to go through a fitting to have that mask fitted properly. That’s why these N95s are just authorized for health care professionals, not the lay public,” she said.
The study was supported by the National Institutes of Health; the Defense Advanced Research Projects Company; the University of California, Los Angeles; the United States National Science Foundation; and the US Department of Defense.
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