In rural America, the problem is worse. One or two missing workers can shut down an entire clinic. Now many are out sick with Omicron. Many rural facilities say they can’t afford to hire travel nurses at rates that have skyrocketed during the pandemic. And some clinics and family practices that typically provide care that can keep people from landing at hospitals are closing because Omicron has hobbled their workforces, too.

Rural hospitals are using veterans groups and foreign nurses to bolster staffing. Some are recruiting unvaccinated workers who were fired elsewhere for failing to comply with mandates to get the shots. And some hospitals are asking workers with Covid-19 to keep working.

“We really feel we have an impending medical crisis here,” said Teresa Tyson, nurse practitioner and executive director of the Health Wagon, a nonprofit clinic that provides free healthcare in Appalachian Virginia.

To keep people out of the hospital, the Health Wagon had been treating people with Covid-19 with monoclonal antibodies. Now they are rationing supplies of the treatment, making it more likely that some will need to be hospitalized, Ms. Tyson said.