COLUMBUS (WCMH) — Thousands of people are traveling across state lines to get vaccinated for COVID-19, as eligibility rules differ in Ohio and its neighboring states.

More than 23,000 people who don’t live in Ohio have received at least one shot of the COVID-19 vaccine in the Buckeye State, according to data from the Ohio Dept. of Health. Most of those individuals, though, live near state lines and work in Ohio health care facilities.

Kentucky and Indiana have similar rules, allowing health care workers living in other states to get vaccinated there. Rules like this make sense to Dr. Ryan Nash, director of The Ohio State University’s Center for Bioethics, who advised Ohio’s vaccine rollout phases.

“I do think states have a primary duty to serve their state’s citizens,” Nash said, adding that Ohio also vaccinates out-of-state patients who primarily seek care in Ohio.

But many Ohioans have contacted NBC4 Investigates to say they feel left behind by the state, whether because they don’t qualify for a vaccine in Ohio but do in a neighboring state, or they qualify here and simply can’t get an appointment. Some told NBC4 they booked vaccine appointments in neighboring states.

“I’m not going to fault people for wanting to pursue their own interests and their own health,” Nash said.

Pennsylvania health officials seem to agree. The Keystone State has no residency or work requirement for a vaccine. Health officials report more than 71,000 people not living in Pennsylvania have received a vaccine there.

“Because the federal government purchased the vaccine, anyone in a priority group should be allowed to receive it, regardless of their place of residency,” said Maggi Barton, a spokesperson for the Pennsylvania Department of Health.

Still, Nash equates so-called “medical tourism” to cutting in line.

“I would urge people to know that it’s only a matter of days or short weeks, usually, before they would be eligible in their home state,” he said.

While each state’s vaccine rollout is designed with slight differences, health officials everywhere are facing the same dilemma.

“It is still a supply issue,” Nash said. “I think as supply increases, the vaccine centers will be able to increase their efficiency in delivering vaccine into those who want it.”