Some key indicators of COVID-19 activity worsened in Minnesota over the past week, but health officials aren't sure they spell more trouble for the state.

Mayo Clinic's 14-day forecast shows an uptick over the next two weeks in infections with the coronavirus that causes COVID-19, but it only brings Minnesota back to the relatively mild pandemic levels of early September.

"For the most part, the model is not predicting a huge rise in the next month," said Curtis Storlie, a co-creator of the Mayo COVID-19 forecast. "As always, the more people that do their part by getting their COVID booster this fall will decrease the chance of any substantial rise in cases ... and help keep COVID out of the spotlight this winter."

Infections publicly reported through clinics and state testing centers remained below 800 per day in late October, well below the average of about 1,300 per day this summer, according to Thursday's state COVID-19 situation report.

The rate of COVID-19 deaths has remained level at about five or six per day, with the risk concentrated among seniors. Of 144 COVID-19 deaths identified so far in Minnesota in October, 126 involved seniors and the rest involved people 50 to 64.

On the other hand, Minnesota hospitals have reported an increase in patients admitted with COVID-19; the total increased from 370 on Oct. 15 to 529 on Oct. 25. Coronaviruses could be combining with other respiratory infections and seasonal ailments to send more people into hospitals even if the COVID-19 rate hasn't changed.

The picture of COVID-19 hospitalizations has changed over time, with fewer people having infections as primary causes of their illnesses and more people having them secondarily, said Dr. Andrew Olson, a hospitalist at the M Health Fairview University of Minnesota Medical Center. He stressed that it shouldn't be minimized, because COVID-19 can increase risks for patients with problems as unrelated as hip fractures.

"There has been some skepticism in the community about saying, 'Are we overcounting patients with COVID?'" he said. "The reality is, whether you are in the hospital for primarily another reason and COVID is something that is found incidentally, it impacts your care."

Sewage sampling at treatment plants in the central, southeast and metro regions of Minnesota showed increases in viral loads, according to the latest results through Oct. 31.

Sampling at the Metropolitan Wastewater Treatment Plant in St. Paul also showed a 21% increase in viral material last week — although the result was influenced by an unusually high sample on one date. Levels increased 8% if that date was omitted from last week's analysis — with updated results due Friday.

Even so, the increases among all wastewater plants only bring Minnesota back to COVID-19 levels it had at the end of the summer. Wastewater sampling remains a predictive indicator of COVID-19 activity, because it isn't influenced by changes in testing levels. Minnesota's infection count is based on publicly reported tests and excludes at-home results.

Signs of exponential growth — which fueled severe COVID-19 waves in Minnesota over the last two winters — have not emerged.

Minnesota hospitals at this time last year had more than 1,000 COVID-19 patients, including 232 requiring intensive care, as the delta variant exploited waning immunity in people who had been vaccinated months earlier. Hospitals reported 50 COVID-19 ICU cases Tuesday.

Health officials suspect Minnesota is benefitting from high immunity rates as a result of recent infections and vaccinations, but are concerned that protections will again wane.

New COVID-19 vaccine boosters have been recommended for people five and older to protect against the dominant omicron strains. But while nearly 4 million Minnesotans have received some COVID-19 vaccine, only 640,000 have received the latest boosters.

Only 12% of Minnesotans 5 and older are considered up to date with their COVID-19 vaccinations as a result, including 33% of seniors at greatest risk.