New COVID-19 cases in Minnesota's long-term care facilities jumped significantly with the spread of the omicron variant, reversing progress made after a successful vaccine booster campaign among residents.

As in other industries, infections also are hitting workers serving long-term care, creating shortages one week before nursing homes must meet a federal requirement to have staff vaccination rates of at least 80%, along with plans to achieve full vaccination by the end of February.

Weekly resident coronavirus infections more than doubled in the first week of 2022 in nursing homes and assisted-living facilities as the highly infectious variant took hold in the state, according to data released Thursday by the Minnesota Department of Health.

Before then, the number of COVID-19 cases had been declining as the rate of residents getting boosters went up. In the state's 360 nursing homes, 80% of fully vaccinated residents have received the booster, up from 12% at the start of November, according to federal health data.

In the week leading up to Christmas, 127 long-term care residents tested positive, the lowest tally since mid-September. But there were 576 cases in the first week of the year, according to preliminary data, with omicron fueling new infections in every corner of the state.

So many Minnesotans are testing positive for COVID-19 that state health officials said Friday that they have a backlog of about 46,000 reports of probable infections that are not yet included in the publicly announced totals.

The reports need to be reviewed to eliminate duplicates and abnormalities. State health officials are retooling workflows to eliminate the backlog, but they emphasized that the 10 highest daily case totals for the pandemic have happened over the past four weeks.

Minnesota could have up to 1.26 million cases while the official tally stands at 1.22 million, including 11,828 announced Friday. Deaths increased to 11,151 with 36 more fatalities, including eight long-term care residents.

On Thursday, COVID-19 hospitalizations had fallen to 1,571, a one-day decrease from 1,629. A total of 241 were in intensive care units. Still, 97% of adult ICU beds were occupied because of COVID-19 and other medical conditions.

Although omicron's impact on long-term care residents has yet to play out, industry leaders said they are hopeful that high vaccination and booster rates will mean lower levels of serious illness and death.

"The good news is with our booster rates we don't have a corresponding increase in deaths like we did before the vaccines," said Patti Cullen, chief executive at Care Providers of Minnesota. "The bad news is it is highly contagious."

Care Providers and another long-term care industry association, LeadingAge Minnesota, are surveying members to learn how many facilities face a staffing crisis.

"Because omicron is so contagious we are seeing staff that are testing positive because we test regularly in our settings," Cullen said.

Gov. Tim Walz has called up 350 Minnesota National Guard members to provide staffing support at long-term care facilities. So far they have been used at 29 homes, including 12 as of Wednesday, according to the governor's office.

"The National Guard teams have been absolutely phenomenal. They've done all kinds of positions," Cullen said. "We are very grateful but we know it is not going to be forever."

Industry leaders are monitoring the impact the federal staff COVID-19 vaccination mandate will have on Minnesota facilities, especially if it prompts some staff members to quit. The rule, issued by the federal Centers for Medicare & Medicaid Services (CMS) that regulates nursing homes, goes into effect Thursday.

"We know that there is going to be a number of providers that are coming forward and saying they could potentially lose a significant number of staff as the CMS vaccine mandate takes effect," said Kari Thurlow, chief executive at LeadingAge.

About 93% of Minnesota nursing home workers have been fully vaccinated, according to federal data. But some homes still have a way to go to meet the 80% threshold next week. About 60 of the 360 facilities have rates below 70%.

CMS is expected to enforce the rule through its routine hospital inspection and survey process, meaning that any financial or regulatory sanctions will happen on a case-by-case basis. Facilities will be expected to have full workforce vaccinations by Feb. 26, except for workers who qualify for medical or other exemptions.

The mandate does not apply to the state's 2,000 assisted-living facilities, which are not regulated by CMS. They would have been subject to a Biden administration vaccine rule for businesses with more than 100 employees, but the U.S. Supreme Court blocked that requirement last week.

Advocates for the elderly said residents need to be protected from unvaccinated workers.

"The real problem is unvaccinated staff and we have far too many that refuse to get vaccinated," said Kristine Sundberg, executive director of Elder Voice Family Advocates. "They are coming and going in their communities and they are freely exposing the residents."