Hundreds of health care workers at the Mayo Clinic have become infected with the coronavirus, even as the prestigious hospital system is treating rapidly growing numbers of patients with Covid-19.

“All of our hospitals are really stretched,” Dr. Amy Williams, who leads the hospital system’s response to Covid-19, said in a news conference on Tuesday. “Many are absolutely full at this time.”

At its flagship hospital in Rochester, Minn., Covid patients occupied all 32 beds in the medical intensive care unit, she said, and the hospital was adding another dozen beds to cope with the inflow of seriously ill patients expected in the next few weeks.

Staffing has emerged as a critical issue, Dr. Williams said. “We are most concerned about not being able to care for patients because of the decrease in our staff due to Covid-19 reasons, whether it is they are exposed and they’re out on quarantine, they’re taking care of a family member who has Covid-19 or they have been infected themselves,” she said.

In the last two weeks alone, about 900 employees have received a Covid diagnosis in Rochester, in the system’s 20 community hospitals in Wisconsin and Minnesota, or in the outpatient clinics it operates there. Both states are experiencing sustained surges in cases that are far worse than at any previous time in the pandemic, with Minnesota reporting nearly 6,000 new cases on Tuesday.

Most of the infections among the Mayo Clinic staff have occurred from community spread, Dr. Williams said, while a few have been traced to exposure from other employees when eating together unmasked. “We’re really not seeing exposures from patient to staff,” she said.

With about 1,500 of its 55,000 employees in the Midwest now sidelined because of the virus, the organization is asking recently retired nurses to come back to work; relocating nurses from its facilities in Arizona; and shifting nurses from other aspects of its operations, like research, to help care for patients. The Mayo hospital system have also cut back on the number of nonessential procedures it is performing.

— Reed Abelson The New York Times