State health officials hope a sobering week of COVID-19 growth in Minnesota will shake people out of the “mitigation fatigue” that has some people ditching masks, gathering close for happy hour, and increasing their risk of viral transmission.

In the seven-day period ending Friday, the state Department of Health reported more than 8,500 new lab-confirmed infections and a tally of 91 COVID-19 deaths — a mortality figure the state hasn’t seen since the end of the pandemic’s first surge in June.

People have taken mask-wearing and social distancing seriously in stores and lately in bars and restaurants — where the pace of outbreaks has ebbed — but they are congregating in social gatherings and group events that are fueling viral transmission, said Kris Ehresmann, state infectious disease director.

“People are getting together for parties and happy hours and kids are hanging out,” she said Saturday. “It’s not the business part of life. It’s the social part of life.”

Tallies this past week included a single-day record of 2,297 infections reported on Friday and a single-day death total of 29 on Wednesday that was the highest since June 5. Cases are rising across Minnesota, rather than being concentrated in certain areas. The state on Friday also reported 484 beds in Minnesota hospitals being occupied by COVID-19 patients, a level not seen since early summer.

Infections have increased in lockstep with more molecular diagnostic testing; the state reported a record of more than 140,000 such tests at public and private labs in the past seven days. Numbers are expected to increase with the opening of three more free testing centers in Winona, Moorhead and Brooklyn Park, where people worried about COVID-19 can provide easier-to-donate saliva samples rather than undergo nasal or throat swabs.

While increased testing might be picking up more mild or asymptomatic cases that weren’t detected earlier, health officials said the latest figures suggest an increase in viral spread.

Positivity rate still high

The key statistic is the positivity rate of tests, said Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy.

In theory, a surge in testing should be diluting the positivity rate, but it has remained around 5% for weeks. The rate of lab-confirmed infections from unknown community sources remains at 38%, another indication that the virus is spreading beyond the ability of state health officials to track it.

One reason for concern: falling outdoor temperatures that will drive people indoors, where viral transmission risk is highest.

“The dark days of the pandemic are about to descend upon us,” Osterholm said, though he added that Minnesotans can “blunt” its impact by diligent social distancing combined with mask-wearing and staying home when sick.

The holiday season also is a concern, because the spread of seasonal influenza historically increases around Thanksgiving and Christmas.

Signs in the southern hemisphere suggest a very mild influenza season, which could reduce fears of both viruses circulating aggressively at once, Osterholm said, but that isn’t a sure thing.

“Anybody who tries to predict influenza, it’s like trying to predict the Dow Jones in 2025,” he said.

Estimates suggest that 10 to 12% of Minnesota’s population has been infected at some point with the SARS-CoV-2 virus, which would mean more than 500,000 people. The official lab-confirmed count through testing now stands at 121,090, including 106,774 people who have recovered to the point they are no longer considered infection risks or required to isolate themselves.

Whether people with prior infections have immunity is unclear, but Osterholm said Minnesota still has a long way to go before achieving a level of “herd immunity” that would choke the spread of the virus.

The Twin Cities metro area was hard-hit early on, but now the virus is sweeping through rural areas — with the 1,704 newly reported infections on Saturday coming from 86 of the state’s 87 counties.

“This thing will hit wherever there is human wood to burn,” Osterholm said. “Sometimes, like forest fires, it skips areas and comes back to burn them later.”

Minnesota remains surrounded by border states with the nation’s highest infection levels. The state’s new infection rate is 233 per day per million people, compared with 800 and 743 in North Dakota and South Dakota, respectively, according to the COVID Exit Strategy website.

Outbreaks are increasing in Minnesota nursing homes, but so far a higher rate of infections involve workers rather than residents, who are at elevated risk of severe COVID-19 due to their ages and underlying health conditions. Mask-wearing, rapid testing and quarantine protocols appear to be protecting residents, who have suffered more than 70% of the state’s 2,208 confirmed COVID-19 deaths.

Ehresmann said she has concern about the infection rates among workers in long-term care facilities, hospitals and clinics, though. The number of such workers who have suffered lab-confirmed infections now stands at 12,315.

Health care workers were commonly exposed to the virus through patients and colleagues in the spring, but last month 62% of their exposures were through household contacts or social events, state health data shows.

Viral exposures can quarantine large groups of workers, leaving hospitals and nursing homes short-staffed at the worst times, Ehresmann said. “We are concerned for what it means going forward, and what impact it will have on our health care system.”