ST. PAUL — More than half of Minnesotans who tested positive for COVID-19 in December were vaccinated, according to state health officials.

The Minnesota Department of Heath breakthrough case data does not indicate if people had received booster shots.

Roughly a third of those who were hospitalized for COVID-19 or died during that month also were vaccinated, the data showed.

“We know omicron was a big part of it,” Daniel Huff, the health department’s assistant commissioner, said of the growth in breakthrough infections. “We know omicron was immune-evasive, much more so than delta. Even those who were vaccinated, even though they had protection against infection, it was less protection than they had against delta infection.”

Nevertheless, health officials say vaccines along with a booster dose remain the best way to protect against severe illness and to slow the spread of the coronavirus.

Vaccinations were never a promise of total protection, but now, health officials say that as the coronavirus has evolved through different variants, they acknowledge there’s an increased risk the vaccinated can still contract and spread COVID-19, the St. Paul Pioneer Press reported.

“The vaccines were initially designed and continue to do an excellent job at preventing severe disease — keeping people out of the hospital, keeping them out of the ICU and keeping them from dying,” said Dr. John O’Horo, a Mayo Clinic infectious diseases expert. “I think we have lost focus on what vaccines are designed to do, which is make this disease manageable.”