MINNEAPOLIS — Minnesota school districts are dialing back in-person learning due to staff shortages during the coronavirus pandemic, as increasing numbers of teachers are either retiring or staying home due to illness or quarantine.

The state has seen explosive growth in cases and hospitalizations in recent weeks, surpassing 7,000 cases in a single day on Thursday for the first time since the pandemic began. The Minnesota Department of Health reported a record 56 deaths on Wednesday; on Friday, more than 1,400 Minnesotans were hospitalized due to COVID-19.

The community spread of the virus has changed where students learn. About 22% of school districts and charter schools across Minnesota began the school year by implementing an all in-person learning model, according to data from the state education department. By mid-October that number shrank to 19%, but as of Friday, just 14% of districts have children doing all in-person learning, as more districts shift to distance and hybrid learning amid the outbreaks.

The Minneapolis and St. Paul districts have both delayed plans to transition to hybrid learning models from their current distance learning models. Anoka-Hennepin schools, Minnesota's largest school district, announced plans Tuesday to transition elementary students to distance learning after the district's middle and high schools moved online last week.

David Law, Anoka-Hennepin's superintendent, said positive cases among the district's 7,200 staff members increased gradually since late September and the district was able to reassign staff or shut down programs as necessary to stay open. But a dramatic spike in infections at the end of October and again last week caused the district to make the decision to shift from a hybrid model to online only, he said.

"Now we have sites that we're really struggling to keep open, where one in five teachers are out on quarantine or ill," he said. "It's predictable that the next week or two we'd have to shut down buildings because we couldn't staff them, and that's where many of my colleagues are already."

Denise Specht, president of teachers' union Education Minnesota, said staffing shortages due to infections or exposure to the virus are becoming more common. She said the number of teachers and substitute teachers was dwindling prior to the pandemic, and she is concerned that the virus seems to be accelerating that decline.

"The longer that this pandemic rages, we're finding more and more people are choosing to leave their employment," she said. "There are some people that are just having to make tough choices and leave the profession because of their own health or their situation at home."

According to data from the Teachers Retirement Association of Minnesota, retirement applications in August and September jumped 35% compared with the same time period last year.

Outside the metro area, Mankato schools superintendent Paul Peterson said that of its 8,700 students and 1,200 staff, the district has only had 76 infections since Labor Day. But as more educators and other school staff are either being infected with COVID-19 or being exposed to the virus and having to quarantine, creative staffing solutions aren't enough anymore, he said.

"We regularly, over the last several weeks, have had principals subbing in classrooms," he said. "It's really been, not just here in Mankato but everywhere, an all hands on deck approach to staffing."

The Mankato Area Public Schools district, in a note to families on Tuesday, announced a transition to distance learning for middle and high school students next week and elementary school students on Nov. 30.

Specht said her biggest concern is the frustration and anger of parents who oppose the school boards' decisions to implement more restrictive learning models. That anger is often directed at educators, which may be contributing to why some teachers are leaving the profession amid the pandemic, she said.

Heidi Hansen, 49, has three kids — one in high school, one in middle school and the third in elementary — in the Centennial School District north of the metro area, which has been implementing a hybrid learning model since September. The district switched its middle and high schools to full-time distance learning this week, and its elementary schools are expected to follow, she said.

Hansen, a preschool teacher who is on leave to be home with her 8-year-old daughter, who has school at home a couple days a week, said she was "disappointed" when the school board voted to move to distance learning. She said she believes younger kids should physically be at school as they are less at-risk, but she understands decisions need to be made to curb the spread of the virus.

"Children of all ages need that in-person interaction and a regular schedule," she said. "I'm frustrated as a parent, however I'm also working hard and consciously to stay as positive as I can because I know the teachers, it's unusual and different for them too."