In the past six months, the 25-bed Ward Memorial Hospital in desert-like West Texas has made countless adjustments to combat the novel coronavirus: It has updated its testing equipment and stocked up on masks and gowns. It created an interdisciplinary team to tackle the virus’s multipronged attacks and traded tips and resources with other regional rural hospitals.

But as fall approaches, it is an old foe that is causing sleepless nights — the possibility that flu could upend this careful planning, diminishing resources and putting further stress on overworked staffers.

“I’ve been a nurse for 28 years, and I’ve never seen anything like this,” said Shawn Nethery, chief nursing officer at the Monahans, Tex., hospital, looking ahead to the possibility of staff shortages if covid-19 cases ramp up and flu strikes with simultaneous vengeance. “It’s so uncertain, like a nightmare.”

Infectious-disease experts have warned of a new and potentially calamitous wave of coronavirus cases this fall, possibly cresting in winter when the flu and other respiratory viruses take hold. That creates particular worries for small, critical-access hospitals such as Ward Memorial that isolated communities rely on for a wide range of health-care needs. But even well-resourced institutions in cities are concerned that a “twindemic” of flu and covid-19 could deplete stockpiles of masks and gowns, force them to compete for testing resources such as chemical reagents and strain weary front-line staffers.

“I worry the most about the ability of the workforce to step into the ring again,” said Brendan Carr, chair of emergency medicine at the Icahn School of Medicine at Mount Sinai in New York City. He said that hospital had been working hard to provide psychological support for battle-hardened health-care workers who have had few opportunities to recharge.

“Adrenaline can only take you so far,” Carr said.

Even without covid-19, the flu is an unpredictable challenge each winter. Every year over the past decade, it has caused between 140,000 and 810,000 hospitalizations and between 12,000 and 61,000 deaths, according to the Centers for Disease Control and Prevention. The numbers differ dramatically, depending on many factors, including the severity of the strain, the efficacy of the vaccine and how willing people are to adjust their behaviors, for instance not going to work when they feel sick.

This year, those uncertainties are greater still, according to Donald Yealy, senior medical director at the University of Pittsburgh Medical Center. He described a range of possibilities: Dueling respiratory viruses that are hard to tell apart could lead to severe complications. Or, the influenza season could be much diminished, with coronavirus practices such as social distancing and mask-wearing also slowing the flu’s spread.

“We don’t know what the fall will bring,” Yealy said. “Our challenge as health-care providers is to have plans.”

Building on groundwork that started in the early days of the pandemic, Yealy hopes to coordinate the use of ventilators and the covid-19 treatment remdesivir — and, when necessary, patient transfers not only across UPMC’s system of 40 hospitals and several hundred outpatient sites but also with the leaders of other systems.

“We have to be harmonized as a region,” he said.

Don Owrey, chief operating officer of six UPMC hospitals in north-central Pennsylvania, said the coordination has introduced a level of shared expertise and experience that has strengthened clinical guidance and the ability to devise practical solutions that he hopes will serve them well as flu arrives. “It grounded us in where we go in terms of science and responding locally,” Owrey said.

While Yealy said UPMC’s system is more sophisticated than many, covid-19 has forced small hospitals across the country to build on existing business links, clinical partnerships or affiliations with larger systems.

Despite the experience health-care workers have gained in managing covid-19 patients, the shortages they face are real, said Nancy Foster, vice president for quality and patient safety at the American Hospital Association. While many have devised means of reusing personal protective equipment, the supply-chain crisis is not over, she said.

“We are still conserving,” Foster said. “To the extent we can do it, we want to walk into flu season as prepared as possible.”

Foster said the AHA is urging the federal government to increase the supply of chemical reagents for testing as both viruses compete for the same compounds and equipment, raising the possibility that emergency-room doctors will not be able to make rapid distinctions between covid-19 and the flu in patients.

Complicating the burden on testing is increased demand from asymptomatic health-care workers, said Lauren Sauer, director of operations at the Johns Hopkins Office of Critical Event Preparedness and Response.

When staffers do need time off, bigger institutions have more flexibility.

“Small hospitals won’t have a deep bench,” Sauer said. “If people go out, there is nobody to backfill them.”

The fact that flu is coming and the coronavirus will be with us “for the long haul” means transitioning both in practice and psychologically from surge mode, Yealy said.

“It’s hard to be in battle mode for an extended period,” he said.

Yealy has encouraged town halls to ensure health-care workers understand the latest science and its impact on strategies adopted by the hospital system, so they are less likely to feel overwhelmed or to second-guess those decisions.

At Mount Sinai, Carr said, major new programs have been instituted around wellness and health that are integrated with anti-racism initiatives. But some approaches, such as shared yoga sessions and free counseling, do not fit the sensibilities of many ER doctors, he said. On the advice of an Army reservist on the staff, his team has set up a “battle buddy” system in which people are paired up and check in with each other regularly. “It’s so simple,” he said. “Watching death gets in your head, and explaining that to a civilian is hard. But everybody gets what peer support is.”

One means of relieving burdens on hospitals is to increase flu vaccination rates. Rebecca Dineen, assistant commissioner for the Bureau of Maternal and Child Health at the Baltimore City Health Department, hopes to vaccinate as much as 70 percent of the city’s population, with a special focus on marginalized populations such as Black and Latino families who have suffered disproportionately from covid-19.

It would be a substantial increase from previous years — and complicated in the age of the coronavirus, when traditional strategies, such as simply showing up and offering shots to people at crowded benefits fairs, are no longer feasible. Instead, the health department is cementing partnerships with health-care providers and other institutions and developing a digital system for residents to locate the nearest doctor’s office or pharmacy where flu shots are available.

“We are trying to use outlets that exist already and don’t force people into long lines of people they don’t know,” Dineen said. “We’ll vaccinate you here; you don’t need to come to us.”

The hope is that when a coronavirus vaccine comes available, “we’ll have figured out approaches to do it safely,” she added.

For now, hospitals are making preparations for a twin pandemic they hope will not hit.

About 250 miles north of Monahans, at the 17-bed Plains Memorial Hospital in Dimmitt, Tex. — population 4,200 — Dana Cobb and her colleagues have been getting inventive.

They brought in an infectious-disease specialist from Amarillo to teach nurses how to rotate — and thus reuse — their masks. They have replaced their clunky ventilator with a more sophisticated model. They have found high-efficiency particulate air, or HEPA, filters for a pop-up isolation tent that will allow them to segregate a few contagious patients. And later this month, they will acquire a polymerase chain reaction, or PCR, machine to test on site for the coronavirus and help distinguish it from the flu and other winter ailments.

“Nurses are known to make the most with what we have,” Cobb, the chief of nursing officer in Castro County, said as she listed the contingency plans. This winter, that could involve commandeering space in the local high school to accommodate an overflow of patients suffering from one respiratory illness or another. “We have to be resourceful,” she said.