For hospitals still facing N95 respirator shortages, expired N95 masks and those sterilized using new decontamination methods are acceptable alternatives, according to a study published Tuesday in JAMA Internal Medicine.
Researchers looked at 29 face mask alternatives to the industry-standard N95s in short supply and high demand amid the COVID-19 pandemic. N95 masks sanitized with ethylene oxide and vaporized hydrogen peroxide retained their filtration efficiencies of more than 95%. N95 masks up to 11 years past their expiration date had the same results.
Surgical and procedure masks fitted with ties were less effective, filtering about 70% of particles, while those secured with elastic ear loops only filtered about 38%.
One of the biggest problems health systems have faced during the COVID-19 crisis is securing enough personal protective equipment, including masks, to keep providers safe.
As the problem became clear, the Centers for Disease Control and Prevention rolled back regulations on when N95s must be used. The agency also offered guidance on their re-use.
Nurses have been angered by the lack of protection,which has helped spark strike threats and other labor actions. In New York, nurses cited lack of PPE in lawsuits they filed against two hospitals and the state health department.
A survey from the country’s largest nurses union found 63% reported they had been forced to re-use an N95, though it did not indicate whether or how the equipment was decontaminated. The JAMA Internal Medicine findings point to the possibility that protection is maintained when proper cleaning is done.
And a separate study from the same publication, also posted Tuesday, found that the rate of positive COVID-19 tests among healthcare workers at a community hospital in Roslyn, New York, was lower than that of the surrounding community. Those researchers said “this is strong evidence that current PPE practices are protective, easing health care workers’ concern and psychological distress.”
The best results from the face mask study came from a Controlled Air Purifying Respirator System (MAXAIR) fitted with a face shield — preventing more than 99% of particles from entering someone’s breathing space.
Those masks and N95 respirators fitted to the face are still the preferred choice of protection against the novel coronavirus, though they’re still in short supply after supply chain issues earlier this year. In a recent survey from group purchasing organization Premier, more than half of hospitals said N95s were heavily backordered.
Researchers conducted the study between April and June in a laboratory setting supplemented with sodium chloride particles to see how well various N95 mask alternatives filtered out particles on a male and female volunteer.
Size was an important factor. N95 respirators in the wrong size had slightly decreased performance, and procedural face masks secured with elastic ear loops were the least efficient of all alternatives.
Another interesting finding involved imported respirators, such as KN95 masks from China. Many have been donated or acquired by hospitals as a potential replacement for limited N95 respirators, though they aren’t an acceptable alternative, according to the study, which found neither achieved 95% filtration. The more effective of the two imported respirators achieved just 80%.
In an editorial published alongside the findings, Caitlin Dugdale, an infectious disease physician at Massachusetts General Hospital, wrote that while competition and price gouging for masks has certainly hindered access, supply is the biggest problem.
Prior to the pandemic, surgical and N95 masks generally cost about 8 cents and 50 cents, respectively, Dugdale wrote. KN95 masks which are not typically sold in the U.S., have been sold during the crisis from $2 to $4 per mask.
“Until we have a better understanding of how filtration efficacy translates to improved protection against SARS-CoV-2 transmission, health care systems are left to pay top dollar to keep their most valuable resources —clinicians and health care workers — safe,” Dugdale wrote.