Single-use N95 respirators can be decontaminated and used again, study
finds
Scientists hope new methods can mitigate the chronic shortage of personal protective equipment

Date:
August 27, 2020
Source:
University of California - Los Angeles
Summary:
N95 respirators, which are widely worn by health care workers
treating patients with COVID-19 and are designed to be used only
once, can be decontaminated effectively and used up to three times,
scientists report.



FULL STORY ==========================================================================
N95 respirators, which are widely worn by health care workers treating
patients with COVID-19 and are designed to be used only once, can be decontaminated effectively and used up to three times, according to
research by UCLA scientists and colleagues.


==========================================================================
An early-release version of their study has been published online,
with the full study to appear in September in the journal Emerging
Infectious Diseases.

N95 respirators reduce exposure to airborne infectious agents, including
SARS- CoV-2, the virus that causes COVID-19, and are one of the key pieces
of personal protective equipment used by clinical workers in preventing
the spread of the virus. Critical shortages of these masks have driven
efforts to find new decontamination methods that can extend their use.

"Although N95 respirators are designed for just one use before disposal,
in times of shortage, N95 respirators can be decontaminated and reused
up to three times," said James Lloyd-Smith, a co-author of the study and
a UCLA professor of ecology and evolutionary biology. "But the integrity
of the respirator's fit and seal must be maintained." In a controlled laboratory setting, the researchers tested several decontamination
methods on small sections of N95 filter fabric that had been exposed to SARS-CoV-2. The methods included vaporized hydrogen peroxide, dry heat at
70 degrees Celsius (158 degrees Fahrenheit), ultraviolet light and a 70% ethanol spray. All four methods eliminated detectable viable virus from
the N95 fabric test samples.

The investigators then treated fully intact, clean respirators with the
same decontamination methods to test their reuse durability. Employees
with the National Institutes of Health's Rocky Mountain Laboratories
in Montana volunteered to wear the masks for two hours to determine
if they maintained a proper fit and seal over the face. The scientists decontaminated each mask three times, using the same procedure with each.

The masks treated with vaporized hydrogen peroxide experienced no
failures, suggesting they potentially could be reused three times,
Lloyd-Smith said.

Those treated with ultraviolet light and dry heat began showing fit and
seal problems after three decontaminations, suggesting these respirators potentially could be reused twice.

The study authors concluded that vaporized hydrogen peroxide was the
most effective method because no traces of the virus could be detected
after only a 10-minute treatment. They found that ultraviolet light and
dry heat are also acceptable decontamination procedures, as long as the
methods are applied for at least 60 minutes.

The ethanol spray, the scientists discovered, damaged the integrity
of the respirator's fit and seal after two sessions, and they do not
recommend it for decontaminating N95 respirators.

The researchers stressed that anyone decontaminating an N95 respirator
should closely check the fit and seal over the face before each reuse.

Co-authors of the study include Amandine Gamble, a UCLA postdoctoral
researcher in Lloyd-Smith's laboratory, as well as researchers with the
Rocky Mountain Laboratories, part of the NIH's National Institute of
Allergy and Infectious Diseases.

Funding sources included the National Institute of Allergy and Infectious Diseases, the Defense Advanced Research Projects Agency, and the National Science Foundation.


========================================================================== Story Source: Materials provided by
University_of_California_-_Los_Angeles. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Robert J. Fischer, Dylan H. Morris, Neeltje van Doremalen, Shanda
Sarchette, M. Jeremiah Matson, Trenton Bushmaker, Claude Kwe Yinda,
Stephanie N. Seifert, Amandine Gamble, Brandi N. Williamson, Seth D.

Judson, Emmie de Wit, James O. Lloyd-Smith, Vincent J. Munster.

Effectiveness of N95 Respirator Decontamination and Reuse against
SARS- CoV-2 Virus. Emerging Infectious Diseases, 2020; 26 (9):
2253 DOI: 10.3201/eid2609.201524 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200827130614.htm

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