Vaccinated people with COVID-19 might be taking up more hospital beds in the latest pandemic wave, but new data from Allina Health and HealthPartners hospital systems show that they often have milder illnesses that don't require intensive care.

The two large Minnesota health systems on Thursday joined with a few others across the country, including Sioux Falls-based Sanford Health, in reporting their COVID-19 hospitalizations by vaccination status and severity. A chart provided by Minneapolis-based Allina showed that only 38 of its 150 patients hospitalized with COVID-19 on Sunday were vaccinated — a rate of 25% — and that only eight of 32 COVID-19 patients in intensive care were vaccinated.

Health officials hesitated over the publication of this data, worried that people would interpret any such COVID-19 hospitalizations as a sign that the vaccine isn't working, but the latest information suggests the opposite, said Dr. Mark Sannes, an infectious disease specialist with HealthPartners and its flagship Regions Hospital in St. Paul.

"Social media is fraught with this right now," he said. "If a vaccinated person gets COVID or gets hospitalized with COVID, the messages they are getting is that the vaccines must not be working. It couldn't be further from the truth. The vaccines are doing very well."

The Minnesota Department of Health on Friday reported 2,645 more infections and 13 COVID-19 deaths, raising the state's total in the pandemic to 681,613 infections and 7,983 deaths. The seven-day average of new infections in Minnesota rose back above 1,000 per day on Aug. 13 and increased to 1,696 Monday — suggesting the peak of the latest COVID-19 wave and the impact of the fast-spreading coronavirus delta variant remains ahead.

The Department of Health has identified 18,790 breakthrough infections, amounting to 0.61% of the state's fully vaccinated population. A rough comparison with total COVID-19 cases suggests that less than 30% of new infections since the start of August have been in vaccinated Minnesotans.

HealthPartners released its detailed breakthrough data in a monthly format, rather than at the current moment in time, and showed that 15.7% of 338 patients admitted for COVID-19 over the past 30 days were fully vaccinated. That compares with an overall rate of 6.3% since the start of the year, when vaccine was limited and rationed for health care providers, long-term care facilities and seniors.

Among HealthPartners' COVID-19 patients in the past 30 days, those who were fully vaccinated made up 11.5% of intensive care admissions and 6.1% of cases requiring ventilators. Sannes said those requiring intensive care tended to be older or have other immunocompromising health conditions. Those groups were less likely to have as robust an immune response to the vaccine in the first place and might be seeing some waning in vaccine effectiveness because they were among the first recipients in early 2021.

HealthPartners reported 42 COVID-19 patients ages 20 to 39 who required intensive care this year and none of them was vaccinated. By comparison, the system reported 145 COVID-19 patients ages 60 to 79 in ICUs this year and nine were vaccinated.

"There's clearly a benefit here," Sannes said. "In the youngest age groups, it's very protective from landing in the intensive care unit. No one vaccinated in that youngest age group lands in the intensive care unit."

While some COVID-19 patients were admitted to HealthPartners hospitals for other reasons first, and only discovered their infections through routine testing, Sannes said that is only about 1% of cases and that most are directly related to the pandemic.

The hospital data concur with a study published Friday by the Centers for Disease Control and Prevention — and co-authored by doctors at HCMC in Minneapolis — showing that COVID-19 vaccines remained strongly effective this summer at preventing hospitalizations in adults without immunocompromising conditions.

The report showed variation, though, with effectiveness in preventing hospitalizations from March 11 through Aug. 15 at 93% and 88% for the two-dose Moderna and Pfizer vaccines, respectively, and 71% for the single-dose Johnson & Johnson vaccine.

The state Health Department has identified 1,095 Minnesotans with breakthrough coronavirus infections who were hospitalized — or 0.036% of fully vaccinated people. The state on Friday also reported a total of 719 people with COVID-19 receiving inpatient care in Minnesota hospitals, including 211 patients needing intensive care.

Sannes said the growing volume of breakthrough data should help guide federal officials next week as they decide whether to recommend third booster doses of Pfizer vaccine for seniors or other groups, and subsequent discussions about the other vaccines.

More than 3.5 million Minnesotans have received at least first doses of COVID-19 vaccine — comprising 73.9% of the state's eligible 12 and older population, according to CDC data, which include doses provided by federal agencies such as Department of Veterans Affairs that don't show up in state data.

State data show that 58% of vaccine recipients have received Pfizer doses while 37.6% received Moderna and 4.5% received J&J.

Jeremy Olson • 612-673-7744