Los Angeles: N95 masks are being widely worn by healthcare workers treating COVID-19 patients. There is this idea that the N95 masks are designed to be used only once. However, the N95 masks can be worn and used up to three after effective decontamination. This information has been given by a new study. It can help reuse these scarce resources amidst the pandemic.
New inputs from researchers
Researchers, including those from The University of California Los Angeles (UCLA), said N95 respirators reduce exposure to airborne infectious agents, including the novel coronavirus, SARS-CoV-2. They are one of the key pieces of personal protective equipment used by clinical workers in preventing the spread of COVID-19.
The study has been published in the journal ‘Emerging Infectious Diseases’. It noted that critical shortages of these masks have driven efforts to find new decontamination methods. Methods through which the use of N95 masks can be extended.
“N95 masks are designed for just one use before disposal. However, in times of shortage, N95 masks can be decontaminated and reused up to three times. However, the decontamination has to be done properly,” said study co-author James Lloyd-Smith from UCLA. “But the integrity of the mask’s fit and seal must be maintained,” Lloyd-Smith added.
In the study, the scientists tested several decontamination methods on small sections of N95 filter fabric exposed to the virus. Among the methods used were vaporised hydrogen peroxide and dry heat at 70 degrees Celsius. Also ultraviolet light (UV), and a 70 per cent ethanol spray were tried. According to the researchers, all four methods eliminated detectable viable virus from the N95 fabric test samples.
The scientists then treated fully intact, clean respirators with the same decontamination methods. It was done to test their reuse durability. Then volunteers were asked to wear the masks for two hours. It was done to determine if the masks maintained a proper fit and seal over the face. The researchers decontaminated each mask three times, using the same procedure with each.
Vaporized hydrogen peroxide most useful
It was found masks treated with vaporized hydrogen peroxide experienced no failures. This suggested they potentially could be reused three times.
Those treated with UV light and dry heat began showing fit and seal problems after three decontaminations. So those respirators potentially could be reused twice, researchers said.
They concluded that vaporized hydrogen peroxide was the most effective method of decontamination. This is because no traces of the virus could be detected after only a 10-minute treatment.
The ethanol spray, however, damaged the integrity of the respirator’s fit and seal after two sessions. So ethanol spray should not be used for decontaminating N95 masks, the researchers stated.