Several COVID-19 trends have improved in Minnesota over the past week, pointing to a peak in the latest wave of the pandemic before health officials hope for another mild summer for the state.

The number of counties in Minnesota federally designated as high risk of COVID-19 fell from 19 to 7, and statewide sampling this week found less evidence of the coronavirus, which causes the infectious disease, in wastewater. The seven-day average of new infections in Minnesota also fell to 1,805 on May 20 from 2,138 per day on May 11 — although that’s based only on publicly reported testing and not home test results.

Minnesota’s COVID-19 hospital admissions rose slightly to 416 Thursday and included 35 people being treated in the intensive care unit. The state also on Friday reported nine more COVID-19 deaths — all among seniors — bringing the pandemic count to 12,628. However, both have lagged behind trends during the pandemic and health officials are hoping they will follow the other downturns soon.

Hospital admissions were less severe in the latest wave — just 8% of COVID-19 patients on Thursday required critical care, compared with 30% earlier in the pandemic. More patients are admitted for other purposes and only test positive at routine screening.

A high level of immunity as a result of vaccination or coronavirus infection this winter reduces the severity of COVID-19 this spring, said Dr. Matthew Prekker, critical care specialist at Hennepin Healthcare in Minneapolis.

“The baseline risk in the population of getting so, so sick – that was there before we had widely accepted vaccines – is much lower now,” he said. “We’re also dealing with less virulent but very transmissible strains of COVID… Fortunately, we’re not seeing nearly as many critical diseases as we did last year.”

Sewage data was mixed last week — when the University of Minnesota showed steady or even falling virus levels in sewage samples from across the state, but the Metropolitan Wastewater Treatment Plant in St. Paul showed an increase. However, the St. Paul plant on Friday reported a 38% drop in viral load in this week’s samples, in line with the latest statewide wastewater trends.

However, virus levels remained the same or slightly higher in wastewater analyzed from six facilities in northeast Minnesota. That aligns with the latest regional risk data from the Centers for Disease Control and Prevention, which found high levels of COVID-19 in Koochiching, St. Louis, Pine and Carlton counties in northeast Minnesota.

Southern counties Freeborn, Olmsted and Winona also retained high-risk CDC evictions, meaning mask-wearing is recommended in indoor public spaces. The CDC designations are based on infection and hospital numbers and are intended to warn communities if there is a risk of bed shortages in their hospitals. Most of the greater Twin Cities area remains at moderate risk from COVID-19, although Anoka and Carver counties are listed as low risk.

Minnesota’s trends are consistent with the northeastern US, particularly in New York, where risk levels and case numbers are falling. The latest US pandemic wave appears to be trending south – with the CDC this week noting an increase in high-risk counties in states like Virginia.

COVID-19 levels have been falling in Minnesota over the past two summers, although they have risen in the Southern states, where hot temperatures are believed to be driving more people indoors and increasing the risk of virus transmission.

Health officials have warned of wildcards that could upset expectations of a mild summer, including the even faster-spreading BA.4 and BA.5 variants that have been spotted in South Africa and are causing a rapid spike in infections there.

These two variants accounted for 11% of the viral load found in wastewater at the St. Paul treatment plant this week, up from 7% last week.

Immunity is also declining over time, and Minnesota is reporting a drop in residents up to date with COVID-19 vaccinations — meaning they’ve completed the first series and booster doses when they’re recommended.

Just 47% of eligible Minnesotans ages five and older are up to date as of Friday, down from 49% last week. Extending booster recommendations to children ages 5 to 11 last week has caused that rate to decrease as COVID-19 vaccine levels decline with age.