More COVID-19 deaths were reported in vaccinated than unvaccinated Minnesotans in the second week of January, but risks remained higher in people who hadn't received their shots.

Unvaccinated Minnesotans made up only 47% of the 163 COVID-19 deaths in the week ending Jan. 15, but they remained at greater risk considering they make up less than 23% of the state's adult population, according to Monday's weekly state report on breakthrough COVID-19 cases.

The data match a national study released Friday, and co-authored by researchers from Bloomington-based HealthPartners, that observed a decline in vaccine effectiveness against the omicron variant. Effectiveness in preventing hospitalizations during the omicron wave declined from 91% in people two months after they received booster shots to 78% four months after they received those third COVID-19 vaccine shots, the study found.

Boosters still offered superior protection, and people shouldn't interpret the results as a reason not to get vaccinated, said Dr. Malini DeSilva, a HealthPartners co-author.

"There is concern that … people could interpret it that way, but what this shows is that there is over 70% protection still against these severe illnesses and that third doses are recommended and provide additional benefit," DeSilva said.

"If people are hesitant about it, we don't know what the next variant is going to be. It's important to provide yourself with as much protection as you can now."

Breakthrough totals are preliminary for the second week of January, which is the second week since May 2 in which 50% or more of COVID-19 deaths were in vaccinated people. The other week was in late October, before booster doses were broadly available. Since May 2, 63% of 3,819 COVID-19 deaths have been in unvaccinated Minnesotans.

Vaccination rates are highest among seniors who also are most likely to die of COVID-19. Adjusting for age differences, the state found the COVID-19 death rate in early January was still nine times higher in unvaccinated people than vaccinated people. The rate had been 15 times higher in late November, when the delta variant was the dominant coronavirus strain.

The findings come on the downside of the omicron wave in Minnesota, which on Monday reported 33 more COVID-19 deaths — including two people in their 30s — and 4,338 confirmed infections. The state's reported positivity rate of COVID-19 testing has declined from 23.6% in the week ending Jan. 10 to 12.5% on Feb. 4.

COVID-19 hospitalizations also have declined to 1,010, including 150 people receiving intensive care. That is the lowest ICU number since Aug. 21, reducing pressure on hospitals and their critical care capacity.

St. Cloud-based CentraCare responded with a "cautiously optimistic" expansion on Monday of its hospital visitor policies, which now allow one healthy adult per patient or two healthy adults if the patient is a child.

Minnesota ranks second in the nation with more than 55% of its 3.8 million fully vaccinated residents receiving boosters, according to the Centers for Disease Control and Prevention.

The CDC on Friday reported that people who received the same Pfizer or Moderna vaccines for all three shots had fewer side effects after boosters than second doses.

Twin Cities doctors said they hoped the latest safety and effectiveness data would persuade hesitant patients.

Dr. Dimitri Drekonja said it often takes heartfelt conversations with his patients at the Minneapolis VA Medical Center after hearing their personal concerns. He recounted one success with a patient who was concerned about vaccine ingredients but had no idea what was in the ink for his many tattoos.

"He laughed and he said, 'You know, you got me, I can't,'" Drekonja said. "That helped sway him."