COVID indicators' mixed signals leave Minnesota threat unclear through late summer

Mixed COVID-19 statistics in Minnesota offer little indication of the direction of the pandemic — other than to say that the coronavirus isn't going away.

New infections held steady in the state at a daily average of 1,402 in the week ending July 22, according to Thursday's state situation update, but viral levels in Twin Cities' wastewater declined by 8% last week.

Severe COVID-19 levels haven't worsened, but they haven't improved either. The 417 COVID-19 hospitalizations Tuesday — 36 involving intensive care — reflected a stagnant number of infected patients this summer.

In the past week, Minnesota verified another 46 COVID-19 deaths — a daily average of about six. That's a slight increase this month but below last winter's peak of 39 per day.

High immunity levels are likely playing a protective role against severe illness, but the dominant BA.5 coronavirus subvariant is showing a unique ability to infect people even if they had recent COVID-19 cases or vaccinations.

Adults who had received initial vaccinations plus booster doses made up 69% of the identified infections in Minnesota in the first week of July and seven of the nine COVID-19 deaths — all among seniors. However, the risk rate remained three times higher among unvaccinated seniors, who accounted for two of the week's deaths despite making up less than 7% of Minnesota's population of ages 65 or older.

"This variant does indeed further evade both vaccine-induced and illness-induced immunity, leading to the risk of further transmission, ever newer variants, and long COVID complications," said Dr. Gregory Poland, head of Mayo Clinic's vaccine research group who participated in a White House COVID-19 strategy session this week.

The Metropolitan Wastewater Treatment Plant in St. Paul is already tracking for BA.2.75, which was designated as a "variant of interest" by the World Health Organization after it appeared in several countries. Some variants with this designation have prompted new COVID-19 waves while others have fizzled.

The new variant did not emerge in the latest Twin Cities sampling, which found that BA.5 made up 70% of the viral load last week. Wastewater sampling is considered a more stable tracker of COVID-19 activity than testing because of the growing popularity this year of at-home rapid antigen tests that aren't reported publicly.

The University of Minnesota dashboard of wastewater sampling in the rest of the state offered a mixed picture of COVID-19 activity as well. Viral loads declined across southern Minnesota after spikes over the past month but remained stable in central regions and increased in the northeast.

COVID-19 levels were higher in Minnesota and the northern states in the spring but then elevated this summer in the southern and western U.S. The lingering question is whether COVID-19 will bounce back with a new wave this fall as Minnesota prepares for next month's State Fair followed by the start of the school year.

The U.S. Centers for Disease Control and Prevention on Thursday said the levels of COVID-19 cases and hospitalizations were high enough in Cottonwood, Hubbard, Jackson, Martin, Nobles, Olmsted and Wadena counties to encourage indoor mask wearing to limit viral spread.

Tracking by Carnegie Mellon University's COVIDcast found the positivity rate of COVID-19 antigen testing jumped in Minnesota after the July 4th weekend — presumably after social gatherings allowed the virus to spread. However, positive tests in the state have since declined and are back below the national rate.

Mayo Clinic's forecast predicts little change in cases in Minnesota for the next two weeks while the COVID-19 Ensemble collaboration of multiple national models suggests little change in hospitalizations but perhaps a slight increase in deaths.