COVID indicators’ mixed signals leave Minnesota threat unclear

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 Minnesota at an average of 1,402 per day 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 on Tuesday, with 36 involving intensive care, reflected a stagnant number this summer of infected patients. Minnesota over the past week verified another 46 COVID-19 deaths — an average of about six per day that is a slight increase this month but is below the peak last winter 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 that week — all among seniors. However, the risk rate remained three times higher among unvaccinated seniors, who accounted for two of the deaths that week despite making up less than 7% of Minnesota's 65+ population.

"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, the head of Mayo Clinic's vaccine research group who participated in a White House COVID-19 strategy session earlier this week. "The extremely low rate of indoor masking (and) low vaccination rates together ensure we will continue to have wave after wave of new variants as the most likely scenario."

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 popped up in several countries. Some variants with this designation prompted new COVID-19 waves while others 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 northern states in the spring but then elevated in the southern and western U.S. this summer. 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.

Cottonwood, Hubbard, Jackson, Martin, Nobles, Olmsted and Wadena counties were listed by the Centers for Disease Control and Prevention Thursday with high enough levels of COVID-19 cases and hospitalizations to encourage indoor mask wearing to limit viral spread. Another 38 counties, including Hennepin, had moderate levels while the rest of the metro area was listed at low risk.

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

Mayo Clinic's forecast predicts little change in COVID-19 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.

The severe delta variant last winter had changed the COVID-19 risk profile somewhat, with only 70% of deaths among the most vulnerable seniors and 30% among largely unvaccinated younger adults. Deaths have declined among all age groups in Minnesota since the winter, but more than 90% this summer have occurred in seniors.