COVID hospitalizations in Minnesota rise to last winter's level

COVID-19 hospitalizations are back to levels not seen since February in Minnesota, and experts are watching the emergence of coronavirus variants that could fuel a fresh wave of illnesses.

Thursday's update still put COVID activity far below the levels Minnesota endured during the global public health emergency, which ended in May. Minnesota's 412 hospitalizations on Tuesday compared with 1,651 on the same date in 2021. But they still represent a doubling of such cases since October — when up-and-down COVID levels raised hopes that Minnesota would avoid another wintertime surge.

COVID has been at its worst during Minnesota winters, but the emergence of new variants is responsible for the latest activity, said Michael Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy. COVID has simultaneously increased in the summer in Australia and Brazil, debunking the notion of seasonality, he added.

"The biggest driver for what happens with cases is which variant takes over," he said.

Surveillance by Minnesota's public health laboratory offers a picture of multiple variants at work rather than a dominant strain. A sampling of infections in early November still found the XBB variants that have been responsible for most COVID illnesses in 2023. However, an EG.5 variant is now responsible for 30% of illnesses and an HV.1 variant is responsible for 26%.

Sewage sampling has identified a 45% increase in coronavirus levels in wastewater statewide over the past two weeks, according to tracking by the University of Minnesota.

COVID levels have accelerated the most over the past two weeks in the Twin Cities and southwest and northern Minnesota, said Dr. Tim Schacker, an executive vice dean for the University of Minnesota Medical School and a supervisor of the wastewater monitoring. "There's a lot of COVID out there right now."

That divergence raises the possibility that an emerging variant is causing a higher rate of severe illness among people it infects, Osterholm said. Immunity levels also have waned because people are farther out from prior COVID infections and only 14% of Minnesotans are up to date with the latest vaccinations.

Research will determine if the latest variants evade the immune protection offered by vaccines, but "the best data we have is that they should surely reduce the risk of severe illnesses, hospitalizations and deaths," he said.

Age remains a dominant risk factor for severe COVID, which has been lab-confirmed as a cause of 15,367 deaths in Minnesota since early 2020. People 75 and older make up less than 10% of Minnesota's population but more then 80% of the 330 COVID deaths reported in the state since the start of October.

Hospital capacity levels remain stable in Minnesota despite the increase in COVID activity, partly because infections with RSV have already shown signs of peaking this winter and the flu season is just getting started.