MISSION, Kan. (AP) — In July, fourth-grade teacher Susanne Michael was ecstatic as she celebrated the adoption of a former student from a troubled home and two of the girl’s brothers. For the festivities, Michael dressed them and her other children in matching T-shirts that read “Gotcha FOREVER.”

By October, the 47-year-old Jonesboro, Arkansas, woman was dead — one of an estimated nearly 300 school employees killed by the coronavirus in the U.S. since the outbreak took hold.

“She just basically would eat, sleep and drink teaching. She loved it,” said her husband, Keith Michael, who is now left to raise the three new additions, ages 3, 8 and 13, along with the couple’s two other children, 16 and 22.

Across the U.S., the deaths of educators have torn at the fabric of the school experience, taking the lives of teachers, principals, superintendents, coaches, a middle school secretary, a security guard. The losses have forced school boards to make hard decisions of whether to keep classrooms open and have left students and staff members grief-stricken.

Harrisburg Elementary, where Michael taught, remained open after her death, but 14 counselors descended on the school the next morning to help distraught students and teachers.

“I can honestly tell you now, none of us would have made the day if it were not for them,” Harrisburg School Superintendent Chris Ferrell recalled, choking up.

At home, Susanne Michael’s death has been particularly hard for her toddler. “He will just point to the sky and say, ‘Mama is up there,'” her husband said.

His wife had diabetes, was a uterine cancer survivor and had just one kidney. Therein lies the main challenge of operating schools: While children generally have mild cases or no symptoms at all, about 1 in 4 of their teachers, or nearly 1.5 million of them, have a condition that raises their risk of getting seriously ill from the coronavirus, according to the Kaiser Family Foundation.

Early research suggested that children are unlikely to contract or spread the coronavirus — an idea that influenced school reopenings in some communities. But Laura Garabedian, a professor of population medicine at Harvard Medical School, said much of that research was conducted during lockdowns when children were home and testing wasn’t being done on those with mild or symptomless cases.

“I think the key question is whether being at school puts teachers at increased risk of getting COVID. I don’t think we know that,” she said. But she added: “There are kids who definitely transmit it, and we know that.”

With community spread rampant across much of the country and contact tracers overwhelmed, it is often hard to tell where teachers are becoming infected.

When cases can be traced back to their source, it is often an informal gathering, a restaurant or a sporting event, not a classroom, said Emily Oster, a Brown University economics professor whose analysis of in-school infection data from all 50 states found that bringing students together in schools does not appear to be driving the spread.

“I don’t think anyone would claim that no one has gotten COVID at a school. That would be unrealistic,” she said. “But in most of the cases we are seeing among people who are affiliated with schools, the actual case was not acquired at a school.”