Mask-wearing was new and controversial during the rise of COVID-19, but infectious disease experts urge Minnesotans to use the practice once more against an old foe in influenza.
Michael Osterholm frequently criticized mask-wearing during the pandemic, because people used low-quality masks and wore them ineffectively below their noses and loosely over their mouths. But the director of the University of Minnesota's Center for Infectious Disease Research and Policy (CIDRAP) was wearing high-quality N95 masks during lectures across Europe this fall, and he stressed that proper masks worn properly can make a difference this winter.
"I am a faithful N95 user and I fit it appropriately to the face and not below my nose. And I think that's what we're talking about," he said. "A lot of these [mask-wearing] recommendations are so generic that the public has no idea what you're talking about."
Minnesota experts are encouraging effective mask-wearing over the holidays — especially by and around people at elevated risk of severe illness — because respiratory viruses spread broadly at this time of year.
"It's never a bad thing to not spread your germs to other people. That's why we use them widespread in the health care setting," said Dr. Will Nicholson, president of the Minnesota Medical Association. He also is vice president of medical affairs for M Health Fairview's east metro hospitals, which have treated patients in ER waiting rooms this fall because of overcrowding.
The stage already is set for a surge in infections because of an early start to the influenza and RSV seasons. Minnesota on Wednesday reported another 241 flu-related hospitalizations in the week ending Nov. 19 — bringing the total so far to 713. Even during a harsher 2017-2018 flu season, Minnesota didn't hit that number until Christmas.
Respiratory viruses have consumed Minnesota's hospital capacity, especially with RSV sending infants and a few older children into pediatric hospitals. More than 8,000 inpatient beds were in use on six days so far in November — a high water mark for Minnesota's hospital capacity. The state on Nov. 15 was down to two available pediatric intensive care beds.
Leading Minnesota pediatricians held a news conference Monday to try to ease the pressure by advising parents when — and when not — to bring sick children into crowded emergency rooms. In general, ER trips are warranted for a sick child suffering dehydration, difficulty breathing or a fever of 100.4 degrees that has lasted more than four days. But they also noted that mask-wearing and prevention can reduce illnesses in the first place.
Public mask-wearing was an oddity in the U.S., seen sparsely at airports, before COVID-19. Interest surged at the outset of the pandemic, causing shortages of elastic, cloth and especially high-caliber N95 masks. Minnesota imposed a mandate in summer 2020 after supplies stabilized, and by the winter nearly 90% of residents were wearing them most or all the time in public places, according to surveys.
The corresponding flu season was historically mild, and doctors believe mask-wearing and social distancing played a role. Only 35 flu-related hospitalizations were reported in Minnesota that season, compared with 2,000 to 6,000 in a typical season. Mask-wearing levels dropped below 60% the following winter — after the mandate was lifted — but flu-related hospitalizations remained lower than usual at 901 for the 2021-2022 season.
Mask-wearing declined in 2022 as COVID-19 risks receded; the latest estimates set the mask-wearing rate in Minnesota around 5%.
The spread of the coronavirus that causes COVID-19 has remained low but steady across Minnesota all fall, according to wastewater monitoring for the virus in 40 treatment plants across the state. The state's COVID-19 death toll has reached 13,663, but the risk is concentrated among seniors, according to Minnesota's weekly situation update. Of 131 COVID-19 deaths in Minnesota so far since Oct. 30, 120 have involved seniors.
Fatigue over masks and political opposition to the controversial mandate resulted in the rapid decline, but people should take advantage of the protection now that there is added proof they protect against flu and other viruses, said Dr. Mark Sannes, an infectious disease expert with Bloomington-based HealthPartners.
"Although we are not in masks for COVID purposes, we have an influenza spike that we could interrupt by incorporating masks into our day-to-day when we are out in public," he said. "I think this could be a tool that we use intermittently and turn on and off during times like these going forward."
Osterholm said he is struck by the amount of ineffective wearing of masks below the nose and mouth, even at a time when people aren't required to wear them. He urged people to take advantage of healthier supplies and use N95 or similar high-standard masks.
Early federal pandemic estimates suggested an unmasked person would transmit an infectious dose of the coronavirus to a face-to-face contact in 15 minutes. Osterholm's CIDRAP made estimates based on industry data and suggested that cloth or surgical masks would only delay transmission in that scenario by another 5 to 15 minutes.
An N95 would keep someone protected from an unmasked, infected close contact for another hour or two, depending on its fit. CIDRAP estimated transmission of an infectious dose would take 25 hours between two close contacts both wearing fit-tested N95s.
Mask-wearing could turn out to be an added precaution against a prolonged and severe flu season, or perhaps just an early one. Fears of a severe season originated in Australia, which had an early spike in sick children, but it dissipated quickly. Other portions of the Southern Hemisphere didn't report severe flu seasons.
Minnesota's RSV and flu-related hospitalizations last week were unusually high for the fall, but both represented slight declines from the prior week.
Health officials stressed that masks work best in combination with other strategies, including washing hands, practicing social distancing, staying home when sick and getting recommended vaccinations.