Amid a shortage of face masks for medical personnel fighting the new coronavirus, two studies show that disposable N95 mask can be sterilised and re-used.
A mask shortage puts health care workers and patients at risk, but the new findings may offer ways to ease that shortage.
Researchers at University of Massachusetts (UMass) Amherst report that an N95 mask sterilised with hydrogen peroxide blocked infectious particles as effectively as a new mask.
Meanwhile, Duke University hospitals in North Carolina's capital region have re-started a mask-sterilisation protocol that had been developed in 2016.
Need to improvise
The key issue: "A used mask could have Covid-19 on it, so reusing it without sterilisation poses a danger to the wearer or to another patient," explained Richard Peltier, an associate professor of public health and health sciences at UMass.
Particulates blocked by the face mask are held inside it, so it must be sterilised if it is not discarded.
However, there were concerns that sterilisation might significantly degrade a mask's filter material, causing it to function improperly.
The new research shows that isn't the case.
"They work just as well after sterilisation," Peltier said in a UMass news release.
Typically, such a test would be repeated dozens of times, but the Boston hospital that supplied the masks couldn't spare any more.
"We are no longer under ordinary circumstances and we have to improvise as best we can," Peltier said.
In related news, Duke researchers confirmed a way to use vaporised hydrogen peroxide to decontaminate masks so they are safe to re-use.
Mask decontamination protocol
Duke routinely uses hydrogen peroxide gas to sterilise equipment and even entire rooms. The process, tested and published by others in 2016, kills germs on the masks after they're worn. The earlier studies did not include fit testing after cleaning to prove the strategy had real-world application.
"We had never considered needing it for something like face masks," said Matthew Stiegel, director of Duke's Occupational and Environmental Safety Office. "But we've now proven that it works and will begin using the technology immediately in all three Duke Health Hospitals."
Duke published its mask decontamination protocol so that other hospitals can use it.
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