Minnesota is organizing its response to the still-mysterious toll of long COVID amid stable or declining levels of the infectious disease this spring.

Twenty doctors and other caregivers are forming a guiding council to study and advise Minnesota on the most effective treatments for long COVID — a cascade of lingering symptoms or health problems following infections with the SARS-CoV-2 coronavirus.

"We still have a lot to learn about long COVID," said Dr. Ruth Lynfield, state epidemiologist and medical director for the Minnesota Department of Health. "But laying the groundwork to expand awareness about the emerging evidence and the available treatments is an important first step toward improving outcomes."

The U.S. definition of long COVID, or post-acute COVID-19 syndrome, is symptoms that linger or re-emerge four weeks after infection. Fatigue and cognitive problems, especially after exertion or exercise, are common symptoms, along with headaches and dizziness.

Minnesota also is launching two surveys to pinpoint the prevalence and severity of long COVID in the state, but an experimental federal online survey suggests it is a common problem. More than 55% of Minnesota respondents in mid-March said they have had COVID-19 at some point and more than 13% reported experiencing long COVID.

Monthly survey results suggest a declining prevalence; nearly 6% of adults reported they were experiencing long COVID in March, down from about 10% in October. Confidence intervals in the surveys suggest the difference could be random chance, but it matches the trend of declining pandemic severity.

Minnesota's weekly pandemic update showed that only 230 inpatient hospital beds in the state were filled with COVID-19 cases on Tuesday, including 18 patients requiring intensive care. That compares to a recent peak of 633 COVID-19 hospitalizations in Minnesota on Dec. 7, and the pandemic record of 1,864 hospitalizations on Nov. 29, 2020.

Duluth-based Essentia Health reacted to the trends Thursday with a switch from required mask-wearing in its northern Minnesota hospitals and clinics to a voluntary stance.

Minnesota is still averaging five to seven COVID-19 deaths per day, reaching a pandemic toll of 14,584 deaths, according to Thursday's update. Death rates have declined among all age groups over the past year, but not as much for seniors — who make up more than 90% of Minnesota's COVID-19 deaths in 2023.

Long COVID consequences are an additional concern. Among Minnesotans dealing with long COVID in March, 83% reported some limitations on usual activities and 23% reported significant limitations, according to the federal survey.

Retired sheriff's deputy Steve Soeffker, 70, said he supports Minnesota's efforts to raise awareness statewide about diagnosing and treating long COVID. He recovered after a 43-day hospitalization for COVID-19 in 2020, but then developed an irregular heartbeat two months later and breathing and balance problems that still plague him today.

Walks across his 10-acre farm in Glencoe, Minn., are no longer possible because of long COVID, he said. "I need to take the tractor. It has changed my lifestyle, my medical needs and my mobility."

Sampling of coronavirus material in sewage, which has proven an accurate predictor of future COVID-19 illness trends, has revealed declining levels in the state since February.

Viral levels at the Metropolitan Wastewater Treatment Plant in St. Paul had declined 61% over the past four weeks. However, the latest statewide readings through March 22 showed slight increases in fringe metro areas and southeast Minnesota, and a substantial increase in south-central Minnesota.

Recent research from the U's Midwest Antiviral Drug Discovery Center offered another reason for caution: emerging coronavirus variants that are resistant to two antiviral drugs including Paxlovid. The drug became widely available in the U.S. last year and is credited with helping to drive down severe COVID-19 rates.

U researchers said their findings underscore the need for continued development of more drugs with different mechanisms for attacking the coronavirus.