Ed Cisek, an Island cab driver, became eligible for the Covid-19 vaccine when it opened to all workers in the transportation and food service sectors on March 22. But getting an appointment on-Island was nearly impossible.

“I went through three rounds of trying to sign up at the hospital,” Mr. Cisek said. “Couldn’t get through at all. I had three phones refreshing at the same time.”

Mr. Cisek finally decided to go off-Island for his vaccine, scouring state vaccination sites online until he found a one-shot Johnson & Johnson dose in Provincetown. The appointment became available at 3 a.m. He booked it immediately.

“I didn’t really want to go off-Island, but I really wanted to get a shot,” Mr. Cisek said.

With only one vaccination site on-Island at Martha’s Vineyard Hospital and supply remaining extremely limited, a growing number of eligible Islanders have decided to look toward the mainland to book vaccine appointments, traveling as far as Western Massachusetts and as close as pharmacies in Falmouth to get their long-awaited shots.

Some Islanders are heading as far as western Massachusetts to get a vaccine.

Ray Ewing

Some Islanders are heading as far as western Massachusetts to get a vaccine.

Ray Ewing

According to Steamship Authority spokesman Sean Driscoll, about 50 Islanders registered with the ferry line to go off-Island for a vaccine shot last week, after the SSA instituted a policy that qualified vaccine shots as medical appointments. The total number of people who went off-Island is likely higher.

“There has definitely been interest in it,” Mr. Driscoll said. “That is a significant increase from the [medical requests] we would normally see in a week.”

The phenomenon is partially a result of circumstance, and partially a result of policy, as the state and federal vaccine rollout focuses on mass vaccination sites and CVS pharmacies for the majority of their vaccine distribution — neither of which exist on an Island seven miles off the coast of Cape Cod.

The Biden administration has an agreement with CVS and Walgreens to provide them with almost half of all vaccine doses as part of their plan to have a site within five miles of every person nationwide, hospital officials said at a briefing Wednesday.

While the hospital has received approximately 1,300 doses of the vaccine per week for the past two months, and requested more, those doses in recent weeks have primarily gone to older patients who need second shots, even as eligibility has expanded to people 55 and older and a wide swath of front-lines workers.

Fewer than 200 first-dose appointments were available for the past six registrations before this week. Online signups have became something of a rat-race, as newly eligible Islanders are forced to compete against each other for sign-up slots.

“I was pretty frustrated,” said Craig MacCormack, who became eligible back in February with patients who were 65 or older but was unable to get an appointment on-Island for more than a month. “I couldn’t get one here to save my life. Of course, I had problems getting online, getting on the phone.”

Hospital officials acknowledged the issue at a press briefing on Wednesday, encouraging frustrated Islanders to explore all available options to get the vaccine.

“I hate the fact that anybody has to leave the Island for anything medical-related, but go get your vaccine,” hospital CEO Denise Schepici said. “Obviously, we love to do it here as much as we can. But I wouldn’t discourage it at all.”

Depending on location, there are limited vaccine appointments that become available across the Cape and South Shore almost daily, including the Falmouth Fairgrounds and Cape Cod Healthcare.

After a few days of seriously searching, Mr. MacCormack eventually found an appointment in Falmouth, going off-Island to get his shot Monday. He said that there were at least two other people who he saw on the ferry and at the CVS doing the same off-Island trip. Mr. MacCormack praised the experience, but said he will have to go off-Island on April 22 for his second shot, as well.

“It was frustrating for a while, but I feel pretty lucky to have it at all,” Mr. MacCormack said.

With food service workers now eligible, the issue has also impacted Island businesses. In a Facebook post, restaurant owner JB Blau wrote that he would be closing the Edgartown Sharky’s until 4 p.m. on Wednesday so that his employees could make a “vaccine run to America.”

Mr. Cisek said that he was able to find his vaccine appointment through a Facebook group called Vaccine Hunters/Angels Massachusetts. The group focuses on giving tips and tricks for finding vaccine appointments throughout the state, including when to monitor state databases and CVS bookings. Mr. Cisek has also been helping Islanders get shots, providing advice in Island-based groups and offering rides to others.

He said multiple people have sent him messages seeking assistance getting a shot off-Island.

“I think a lot of people are looking at it as an option,” Mr. Cisek said. “There’s just more availability to shop around for appointments when you’re on the mainland.”

This week, as the number of first and second doses provided by the hospital have nearly caught up to one another, schedulers were able to offer more than 600 first-dose hospital appointments on Monday, clearing part of the backlog. But with eligibility set to expand to all residents 16 and older on April 17, the bottleneck could get tighter.

“This is nothing against the hospital. They are doing the best job they can do,” Mr. Cisek said. “We just need more supply, because it’s not reasonable to send people off.”