As the Island’s vaccine supply grows, demand for vaccinations on the Vineyard has declined, hospital officials confirmed Wednesday, echoing trends around the state and country, and marking another tidal shift in the battle against the pandemic as summer approaches.

“Just as we finally have a robust supply, the demand for the vaccine is dropping, and that is not a good sign,” hospital president and CEO Denise Schepici said at a press briefing Wednesday. “We’re getting close, but we’re still far away.”

The hospital is the only state-approved vaccine clinic on the Vineyard.

After months of bottlenecks in appointment signups, the Island vaccine supply recently expanded dramatically. Under a new partnership with Island Health Care, a federally qualified community health center, the Vineyard has been receiving additional doses from the U.S. government, beginning with 4,040 vaccine doses last week. The shipment dwarfed that of previous state allocations, which were around 1,300 weekly.

But the once-bust and now-boom supply cycle has left appointments unbooked and doses unused — a dramatic shift from the past three months.

Statewide, the trend is similar.

On Monday, Gov. Charlie Baker announced that the commonwealth would close four of its seven mass vaccination sites, shifting the focus toward smaller regional vaccine clinics instead. On Wednesday, he announced walk-in appointments would be available at CVS pharmacies.

At the briefing Wednesday, Claire Seguin, head nurse and chief operating officer at the hospital, said about half the vaccine shipment last week was used for first doses and another quarter for second doses. The remaining vaccine supply — about 1,000 doses — was stored for later use this week.

“We thought when we had a whole bunch of new doses to give that those [appointments] would fill up really quickly, and they didn’t,” said Ms. Seguin. Based on recent demand, the hospital has ordered 2,200 vaccines — just over half the previous shipment — for next week. Unused doses can be stored for months in the hospital’s deep freezer, Ms. Seguin said.

Though the Island’s remaining unvaccinated population is hard to pin down, Ms. Seguin said younger residents make up a large part of those who have not received shots.

According to state Department of Public Health and 2019 census data, in Dukes County 92 per cent of people aged 65 to 69 and over 95 per cent of those 70 and over have received at least one dose. By comparison, 51 per cent of residents aged 20 to 29 and 35 per cent of those 15 to 19 have received their first shot.

“I’d say it’s a younger group [that is] probably working and busy and it’s harder to fit it in,” Ms. Seguin said.

A recent trend of cancellations and no-shows for second dose appointments has also contributed to the extra supply, hospital officials said, with some people rescheduling for new dates or shifting to other locations for their shots.

Ms. Schepici stressed that more vaccinations are paramount for the Island before the expected influx of summer visitors. “My main concern of course is . . . the whole Island, our economy, our safety — we want the Islands and . . . state . . . basically to get back to some semblance of normal,” Ms. Schepici said. “And you know the vaccine is just a step in that right direction.” She urged Islanders who have not been vaccinated yet to get signed up. “The virus is still very, very potent and it’s out there and I don’t want people to have a false sense of complacency,” Ms. Schepici said.

As of Tuesday afternoon, the hospital had administered 19,630 total doses, including 11,777 first shots. A total of 7,853 Islanders have received two shots. According to DPH and 2019 census data, 67 per cent of the county has received a first dose and 42 per cent are fully vaccinated.

The rates remain among the highest in the state, alongside Nantucket and Barnstable counties.

Vaccination rates have also begun rising among the Island’s black and Brazilian communities, Ms. Seguin said, while a new offer from the hospital to administer second doses to those who received their first off-Island has already brought in 150 people.

Looking ahead, as the FDA eyes approving the Pfizer vaccine for children between the ages of 12 and 15, Ms. Seguin said the hospital has increased its ratio of Pfizer supply in weekly shipments. If the age group is approved, the hospital stands ready to vaccinate the estimated 550 kids in the 12-15 age group, she said.

A recent limited supply of Johnson and Johnson vaccine will also help bolster the Island’s vaccine supply, as the hospital works with IHC to fold the single-dose vaccine into clinic operations.

Ms. Seguin said she was confident the hospital would reach its goal of offering vaccinations to the entire Island community by Memorial Day. “I think we can absolutely do it,” she said.

In other business Wednesday, hospital officials said they were awaiting the results of additional variant testing after the contagious B.1.1.7, or UK variant, was detected on the Island at the beginning of April. Ms. Seguin said the state lab is currently analyzing two Covid positive tests for other possible variants, with results expected soon.