Shantanu Singh is an experienced critical care physician who is also trained in pulmonology — the medical specialty that deals with lungs. In short, he is exactly the kind of doctor who is desperately needed on the front lines of the coronavirus epidemic right now. While New York City hospitals are overwhelmed, with patients dying in makeshift emergency rooms and remaining on gurneys awaiting hospital beds for more than a day despite being extremely sick with Covid-19, in Huntington, West Virginia, where Singh lives and works, the virus has yet to wreak havoc. Because his schedule gives him 15 days off in a row, he could easily travel to New York or another area to help out without even taking time off from his job. And Singh would like to help. “It’s what I’m trained to do,” he said.

But it is illegal for Singh to travel to one of the places that desperately need his help combating the novel coronavirus. Even though he did his medical training and works as a doctor in the U.S., because he was born in India, Singh cannot heed the calls for physicians coming from New York City and other parts of the country that have been hardest hit by Covid-19. His “exchange visitor” visa, a type known as a J-1, leaves him unable to do paid work or even volunteer for any hospital other than the one that sponsored his visa.

“My skills are not being used in this country,” he said.

Singh is not alone. The U.S. has more 10,000 physicians who were trained in the U.S. but are unable to work for any hospital other than their current employer because of visa restrictions, despite the historic public health emergency.

More than one-quarter of physicians in the U.S. are foreign-born. Among trainees in pulmonology and critical care medicine — the specialists most needed to combat this coronavirus, which ravages the lungs — more than 40 percent are born outside the U.S. Yet many of these doctors — more than a third of those practicing in this country who graduated from international medical schools — have either exchange visitor visas or other types of visas for temporary workers like the H-1B that limit their ability to work.

Green cards are allotted by country, and there is a particularly long wait for permanent residency cards for Indian citizens. Three-quarters of skilled workers waiting for green cards are from India. That translates to more than 700,000 people, according to a policy brief published last week, some 200,000 of whom are expected to die of old age before being granted green cards. In the meantime, while they live with restrictions on both their employment and mobility, many Indian physicians are doing essential medical work in underserved and rural areas throughout the U.S.

The green card backlog, which has been a chronic frustration for Indian-born doctors, is particular vexing during the pandemic. Both New York Gov. Andrew Cuomo and New York City Mayor Bill de Blasio have recently made desperate pleas for anyone with relevant medical skills to immediately enlist in the fight against the coronavirus. Even elderly doctors, who are particularly vulnerable to Covid-19 because of their age, have come out of retirement to help combat the outbreak.

“We’re watching as people trained as urologists or orthopedic surgeons are stepping up,” said Ramakrishna Yalamanchili, an internist practicing at Logan Regional Medical Center in Logan, West Virginia. “They’re even putting medical students on the front lines.” Like Singh, Yalamanchili is Indian, well-trained to do coronavirus treatment, and eager to travel to help fight the outbreak. “I want to go and volunteer where they need us,” he said, adding, “We want to help prevent the spread before it comes here.”

Yet Yalamanchili, who is on an H-1B, a type of temporary worker visa for specialty occupations, is not only unable to travel to work in any of the coronavirus hot spots — because of the strict rules that allow physicians to work only in the department that sponsors their visas, “we cannot even help within our own hospital if it’s for a different department,” said Yalamanchili. While he frets about his inability to use his skills to help the country, he also worries he may ultimately be unable to help his wife. “What if, God forbid, I get sick with Covid and something happens? She’ll be deported back.”

The bureaucratic obstacles to foreign-born doctors who are eager to help but unable to do so could be quickly eliminated, according to the Society of Hospital Medicine. The organization wrote to House Speaker Nancy Pelosi, Senate Majority Leader Mitch McConnell, and others last week asking them to “act now” to give the 10,000 immigrant doctors who have trained in the U.S. and are now caught in the green card backlog permanent resident status, explaining that the move would “give these providers and their families peace of mind while putting themselves at risk in caring for our nation’s populace.” The group also requested that clinicians on H-1B visas be granted permission to work in hospitals that have not sponsored their visas and an automatic extension of their visas.

Even if they do immediately change the rules, the ability to deploy these desperately needed doctors will come too late for some. Almost 10,000 people in the U.S. have already died from the coronavirus — a number that is likely a vast underestimate due to the ongoing lack of testing. As the number of new infections continues to climb and physicians on the front lines are increasingly overwhelmed both by their work and by the virus itself, which will infect untold numbers of health care workers, the shortage of doctors prepared to do the kind of medicine that coronavirus patients need will only grow and contribute to the devastation.

For Paavani Atluri, watching the pandemic unfurl from Coos Bay, Oregon, is painful on multiple levels. “It is emotionally and ethically taxing,” said Atluri, a physician who was born in southern India and did her medical residency at Monmouth Medical Center in New Jersey — an area she now considers home. The hospital where she works has been working hard to support doctors and brace for the impact, but there has been only one confirmed Covid-19 case in surrounding area of coastal Oregon, and it was well controlled. Meanwhile, the virus is exploding in parts of New Jersey. And Atluri has heard from former colleagues there who are pressed to their personal and professional limits by the pandemic.

“One friend from Pakistan who is doing her third year of residency just lost four patients in a shift,” she said. “If I were not born in India, I would have had my green card now and could be there helping.”

If the policy changes, Atluri said she will help out wherever and however she is needed. After that, her plans are less clear. Even before the coronavirus, she had found it increasingly difficult to practice medicine in the U.S. “The pandemic has made it worse,” said Atluri, who cited the lack of protective equipment and testing along with the strict visa limitations among her most pressing disappointments. “We say that the U.S. has the most advanced health care system,” she said. “But looking at how we’re not able to treat doctors better, it makes me think about leaving.”