Few Minnesotans sought COVID-19 vaccine to reduce their infection risks this winter, but at least the shots offered some protection for those who did.

The current vaccine was 33% effective at preventing emergency room and urgent care visits among adults who got COVID, according to interim federal estimates published Thursday. HCMC in Minneapolis and HealthPartners in Bloomington contributed to the federal report.

The vaccine also was about 45% effective in a five-month period this fall and winter in preventing hospital admissions among elderly adults with healthy immune systems, the report showed.

During the pandemic, the initial vaccines appeared 70% to 90% effective at preventing admissions, but at that point few people had exposure to the coronavirus that causes COVID-19, said Dr. Matthew Prekker, an HCMC physician and a coauthor of the report.

Now that most people have been infected, "there is a baseline level of immunity in the community, even independent of vaccination status," he said. "So the fact that the current vaccine is providing additional protection, even on the margins, is really important."

The effectiveness data is now more in line with yearly estimates on how well the seasonal influenza vaccine is working, he added.

The Centers for Disease Control and Prevention recommends COVID vaccinations for people starting at 6 months old. Whether that changes is unclear now that vaccine skeptic Robert F. Kennedy Jr. is secretary of U.S. Health and Human Services, which oversees the CDC.

Kennedy has long voiced concerns about vaccine side effects and postponed this week's meeting of the Advisory Committee on Immunization Practices. The committee has traditionally guided the CDC on vaccine recommendations.

Minnesota's weekly update on Thursday showed a continued decline in COVID activity after it peaked in January. Influenza had crowded Minnesota hospitals after the holidays, but its spread has diminished in recent weeks as well.

While 33% of Minnesotans were up to date this winter with recommended flu vaccinations, state data showed, only 20% were up to date with COVID booster shots.

Even with a brief uptick this winter, COVID remained far less of a problem in Minnesota than it did during the pandemic era, from 2020 to 2023.

Levels of vaccination and severe COVID were low enough this winter that the CDC research group didn't have enough patients in their data to reliably determine if the vaccine protected children, prevented hospitalizations among non-elderly adults, or prevented anyone from suffering severe COVID complications or deaths.

The results still favor vaccination, said Prekker, who treated patients with COVID in HCMC's emergency room and intensive care unit this winter. "Our conclusion still rings true."