More than 700,000 Minnesotans have tested positive for coronavirus infections during the COVID-19 pandemic that has stretched on for 19 months, the Minnesota Department of Health reported Tuesday.

Minnesota surpassed the pandemic milestone with the addition of 6,203 infections reported Tuesday, though the actual infection total is higher given the number of people with mild or asymptomatic illness who never sought testing. The state also reported 11 deaths, raising its toll in the pandemic to 8,109. Tuesday's update reflects COVID-19 activity detected over the weekend.

Minnesota's total of 706,158 infections means that more than 12% of its population of 5.6 million people has tested positive. University of Minnesota infectious disease expert Michael Osterholm said the actual rate is much higher, having estimated a year ago that as many as 30% of Minnesotans had been infected.

The key question is how many people are left who haven't gained at least temporary immunity through a previous infection or COVID-19 vaccination, said Osterholm, director of the U's Center for Infectious Disease Research and Policy. "What this virus has continued to demonstrate is its ability to find people who are not vaccinated."

Minnesota on Tuesday reported a 6.6% positivity rate of recent COVID-19 testing, a decline from 7.1% last week that raises hopes that the latest pandemic wave is peaking. COVID-19 hospitalizations increased slightly to 767 Monday, but remained below a high of 794 last week.

Nationally, the COVID-19 map has flipped from earlier this summer. Minnesota ranked 28th worst among states for its infection rate in the seven-day period ending Sept. 23 — with rates lower in states such as Missouri and Florida that had early and severe COVID-19 surges, according to a federal profile report released Tuesday.

Alex Kormann, Star Tribune file, Star Tribune

Minnesota ranked 12th lowest among states for COVID-19 hospitalizations and eighth lowest for deaths in that week.

State health officials said the first-dose vaccination rate of 74.6% of eligible residents 12 and older could be preventing more severe illness — based on data showing that the vaccines are strongly protective against hospitalizations and COVID-19 deaths.

Sanford Health on Tuesday reported that 12 of 158 COVID-19 patients admitted to its hospitals in the Dakotas and Minnesota were fully vaccinated. However, only two of its 47 COVID-19 patients in intensive care — and none of its 28 patients on ventilators — were vaccinated.

Minnesota officials are asking unvaccinated people to get the shots and eligible people who got the Pfizer vaccine to seek third booster doses.

The state followed federal guidance last week in advising Pfizer boosters for people who are older than 65 or older than 50 with underlying medical conditions. Providers also can give boosters to people 18 to 49 with underlying medical conditions and people 18 to 64 at increased risk of workplace viral exposure. Recommendations about boosters for the two-dose Moderna and single-dose Johnson & Johnson vaccines are pending.

Seniors remain more vulnerable to COVID-19, making up 12% of Minnesota's diagnosed infections but 87% of its deaths so far.

Infection numbers have increased since July with the emergence of the fast-spreading delta variant. The rolling seven-day total of new infections diagnosed by testing reached a low of 613 for the week ending June 26 — shortly after Gov. Tim Walz lifted a mask mandate.

Case growth has increased to 15,956 infections in the one-week period ending Sept. 22.

Minnesotans 19 and younger are a larger share of the latest wave — less than 20% of infections overall but nearly 26% of infections identified since the low point in late June.

"The case numbers only begin to capture the impact of the pandemic on Minnesota," state Health Commissioner Jan Malcolm said. "It's important that we do our part by getting vaccinated."

Jeremy Olson • 612-673-7744