Before the current pandemic, doctors wore surgical masks mainly in the operating room to protect from splashes, spills, or droplets. In the medical setting, N95 respirators—which offer protection against airborne infectious pathogens like tuberculosis—were needed far less often. That is, until COVID-19.
“Right now we're using many-fold the number of N95s that we normally did prior to this pandemic,” says Patrick Kenney, MD, medical director of Supply Chain for Yale New Haven Health and clinical vice chair of the Department of Urology. “A lot of the supplies we have actually are a result of the Ebola crisis preparations. So the American health care system in general was better prepared for the crisis at hand because of Ebola.”
But, demand for respirators has skyrocketed during the coronavirus pandemic.
Kenney and co-authors of a recent Yale study now published in pre-print form in MedRxiv have found an emergency solution to help hospitals with the shortage of N95 respirators. They found that a majority of N95 respirators are still in good enough shape after being worn that they don’t need to be thrown away. Instead, they can be reprocessed using vaporized hydrogen peroxide.
“We were able to demonstrate that respirators inoculated with aerosolized viruses were able to be sterilized with exposure to vaporized hydrogen peroxide,” he says. “We've noted that about 80% of the respirators are able to be reprocessed, that they're in good enough shape because they're not visibly soiled, not covered in makeup, or damaged in any way.”
Researchers inoculated the masks with three viruses used as proxies for SARS-CoV-2 and processed them using this method. Testing showed no evidence of residual virus. With this system, a room full of N95s, containing more than 1,000 respirators hung on racks, can be cleaned all at once using a system used to fumigate hospital rooms. The system is made by Bioquell in PA and is technology Yale New Haven Hospital already has.
Kenney says that this respirator cleaning technique is a back-up plan to be implemented only if the supply of N95s becomes dangerously low, which it now is.
“Our supplies of two types of N95 respirators have declined, and we are now going to be putting reprocessed versions of those N95s into circulation,” he says. “It is a challenging environment, but we are prepared and hopeful.”
The study is currently awaiting publication and peer review. However, the Centers for Disease Control and Prevention (CDC) cited the study in a new document about decontamination strategies that may be considered during the pandemic to help ensure continued availability of N95s for health care workers.