Reporter Erin Billups examines the potential effect of the Trump administration's so-called travel ban on health care, as part of the Spectrum News special "Immigration in America."

Twenty-three percent of medical students who applied for match in 2017 residency programs are non-U.S. citizens from international medical schools.

Almost a quarter of the students finding out where they will take their residencies in the United States are foreign born -- applying from international medical schools.

This year though, about 500 match applicants could have been impacted by the Trump administration’s so-called travel ban, an executive order limiting travel from six majority Muslim countries.

Dr. Susan Grossman directs the Internal Medicine residency program at NYC Health+ Hospitals/Woodhull. It’s one of 11 city-run hospitals where more than a fifth of doctors are foreign born.

"All over the country, there are thousands of residency spots, more than there are residents from U.S. schools to fill the spots," she says.  "For the international graduates, we really only take the best of the best, it's very competitive. And we are able to get doctors of extremely high quality."

Most foreign-born doctors gain entrance to train in residency programs at U.S. hospitals through the visa categories H1B and J1, for foreign professionals.

Depending on the type of work applicants are engaged in, they can apply for a green card and, after three to five years, permanent citizenship.

"They know that one route to becoming a fully licensed physician is to participate in the J1 or H1B program," says Dr. Wayne Riley, President of SUNY Downstate Medical Center.

Nearly 20 percent of doctors caring for patients in the U.S. are foreign born.

But there are concerns that stricter traveling and exchange rules will make the country's growing doctor shortage worse.

It's estimated about 9,500 of foreign born doctors serving in the U.S. are from countries where the current administration is looking to limit travel.

"The demographics of the country are changing -- we’re an older country and we’re a country where there’s a higher life expectancy," says Riley.  "With that comes the use of a lot of health services, so ergo, we need more physicians participating in patient care.  So you can see, if we lose anywhere from 10-20 percent of the physician workforce  because of a too restrictive immigration policy, whether of the J1 or the H1B visa program, that can have a significant adverse effect that we those of us in health care and medical education fields are very worried about."