ST. PAUL — Flu is now widespread in Minnesota, a sign this year’s influenza season will be harsher than most, the Minnesota Department of Health said Thursday.

The designation means influenza has been detected in four of the eight reporting districts in the state.

Sixty-five people were hospitalized for suspected influenza infections in the week ending Dec. 6 — the highest total for the first week of December in the past six flu seasons.

More than 185 people have been hospitalized so far this season, with many cases involving a specific influenza A strain that has been known in past years to cause more severe illnesses. Minnesota also has reported 64 outbreaks of influenza-like illness in schools and seven outbreaks in long-term care facilities so far this season.

Health officials are encouraging people to get flu shots, despite reports that the vaccine is less effective this year and poorly matched to the dominant strains in circulation. Mayo Clinic pediatrician and vaccine researcher Robert Jacobson said even weaker protection is still protection.

“People who get the flu shot have better protection even when there’s a mismatch,” Jacobson said. “They often get less severe a case of the flu and they’re less likely to spread the flu to someone else.”

The state Health Department has reported one pediatric death related to the flu so far this season. The death of an Owatonna High School teenager on Tuesday came after she suffered flu-like illness, but tests haven’t confirmed whether influenza played any role.

Flu achieves the “widespread” designation in Minnesota almost every influenza season. Last season, the designation was announced in late December. But often, influenza doesn’t reach that level in the state until after the new year.