Hospitals are using ultraviolet decontamination to stretch their supply of high-filtration N95 masks that protect doctors and other caregivers amid the COVID-19 pandemic, which to date has caused 87 deaths and 1,809 lab-confirmed infections in Minnesota.

M Health Fairview hospitals now allow N95s to be reused up to six times if they are decontaminated after each use and remain intact — which dramatically increases its capacity of personal protective equipment, or PPE.

“We’re hopeful we can get at least two times [more use out of masks] or up to six times, somewhere in that range,” said Dr. Abraham Jacob, M Health Fairview’s chief quality officer.

A PPE shortage has been a grave concern for Minnesota health officials as they predicted the course of the COVID-19 pandemic, which is caused by a new, highly infectious coronavirus to which nobody initially had immunity. Nurses have voiced concerns as well about a shortage, but also about the safety of reusing decontaminated masks.

Gov. Tim Walz unveiled wide-ranging estimates last week, including that Minnesota could run out of PPE at the peak of the state’s outbreak this summer. The governor said he is feeling more confident this week due to new shipments, efforts to stretch existing supplies, and the possibility that COVID-19 outbreaks in other states will peak and reduce nationwide PPE demand.

“Those are the things that keep you up,” Walz said of a mask shortage. “I think there’s reasons to believe that we are building toward the capacity that we need.”

New problems emerge, though. Minnesota’s emergency stockpile has increased from 377,000 N95 masks on April 7 to 409,000 now — with another 1.6 million scheduled for delivery. But the state lists a supply of only 68,000 gowns — and no more set for delivery.

Walz on Wednesday also reiterated his demand for medical providers to increase the state’s capacity for diagnostic molecular tests for COVID-19 to 5,000 per day. He also wants thousands of daily antibody tests, such as those recently unveiled by the University of Minnesota and Mayo Clinic, to determine when people have recovered from infection.

“Until we get a vaccine, we are going to have to be able to identify who is sick,” he said.

Mayo is hoping to double its capacity from 10,000 to 20,000 antibody tests per day so that it can perform surveillance to understand the breadth of the pandemic, said Dr. William Morice, president of Mayo Clinic Laboratories.

“One of the uses for this test at some point will be to test as many individuals as possible so we really have a good sense of how much this infection has actually spread,” he said.

‘Uncharted territory’

Duluth-based Essentia Health adopted an N95 mask decontamination process this month that was developed in Nebraska and listed as a “promising” contingency by the U.S. Centers for Disease Control and Prevention due to any shortages.

HealthPartners on Wednesday announced plans to use ultraviolet light from a disinfecting robot to treat hundreds of N95 respirator masks daily. Allina Health and Mayo Clinic are exploring technological options, too.

“We are in uncharted territory, and we need to be flexible,” said Dr. Mark Sannes, a senior medical director at HealthPartners, a Bloomington-based health system.

Nurses’ union leaders have objected, though, citing concerns that certain UV decontamination approaches might leave residue or substances on the masks that would be harmful for nurses to inhale.

“I find it very alarming that everyone is getting so excited about this because they could look up the same research,” said Mary Turner, president of the Minnesota Nurses Association and a critical care nurse treating COVID-19 cases at North Memorial Health Hospital in Robbinsdale.

Union leaders are lobbying Minnesota’s congressional delegation to instead urge President Donald Trump to enact wartime levels of production nationwide of masks.

HealthPartners said in a statement that Maplewood-based 3M, the mask manufacturer, conducted tests that confirm N95 respirators could be decontaminated up to 10 times without causing significant damage to fit and filtration. Fairview and 3M also collaborated on weeks of testing to make sure the UV treatment caused no degradation or holes in the masks.

3M in a technical guide this month said it is examining multiple methods of safely sterilizing N95s but discourages the use of ethylene oxide due to inhalation risks, as well as ionizing radiation, microwaves or high temperatures that damage the masks.

Normally, doctors and nurses treating a patient would discard N95 masks between patients, Sannes said. Now, caregivers are using one N95 mask per day.

Some caregivers have been following a CDC-listed strategy of putting masks into paper bags at the end of shifts, and not using them for five days, because the virus can’t survive that long, Sannes said. With robotic disinfection, at the end of shifts caregivers put their masks on designated shelves for cleaning.

Unlike common medical masks, N95s are fitted to provide extra protection, meaning they can’t be tossed in group bins for decontamination.

At Fairview hospitals, caregivers put the masks in paper bags and write their names on them. At a time when items as simple as cotton swabs for lab testing are in short supply, Jacob said he has contemplated the possibility of paper bags running short.

Early signs of payoff

Minnesota on Wednesday reported another 114 lab-confirmed COVID-19 cases and eight deaths — all in long-term care facilities.

State health officials have responded with increased training and oversight of long-term care facilities, because residents are at higher risk of severe infections due to their age and health status.

State Health Commissioner Jan Malcolm said there are early signs of a payoff. While 108 long-term care facilities have reported outbreaks involving infected workers or residents, only half have had more than one case.

“It really does suggest to us that infection control is really helping limit the spread of those infections,” she said.

Shortages of personal protective equipment affect long-term care facilities as well. Walz said the state needs millions more PPE items than it has in stock, and he has been frustrated by the irregular supply coming from the federal government as well as a seizure of items in China that had been bound for Minnesota.

In the last week, though, Minnesota companies have stepped up efforts to secure masks and other supplies from their locations around the globe, said Alice Roberts-Davis, commissioner of the Minnesota Department of Administration who is heading up the state’s COVID-19 supply procurement.

“We are starting to see a pretty steady flow of PPE into the state that we are able to get to our front-line health care workers,” she said.

Staff writer Glenn Howatt contributed to this report.