After much debate about logistics, and delays caused by vaccine shortages, it appears likely that all Vineyard residents will be offered vaccination against both swine flu and regular flu, at a single big clinic, on Nov. 11.

A meeting of the Island’s various town health agents, school nurses, tribe and other public health officials late yesterday agreed on that date and the venue — the regional high school — with one proviso, that the state comes through with enough vaccine to allow it to proceed.

“Certainly Nov. 11 is our firm choice,” said Edgartown health agent Matt Poole after the meeting, “but we can’t formally announce it will happen that day, because it is unknown at this stage if the state will be able to fulfill their offer of vaccine,” he said, adding:

“We will know for sure in coming days. If it all unravels, we will reconvene to discuss a plan B.”

The uncertainty arises from the fact that the state has twice failed to deliver on promised vaccine supplies — for regular seasonal flu rather than H1N1 — and now appears to be rushing to meet demands from Washington that it get its vaccination program moving.

Last week, the White House contacted governors’ offices in every state regarding the national response to H1N1, urging them to begin scheduling vaccination clinics as soon as possible.

This week, the state Department of Public Health (DPH) in turn hustled to identify communities which could be prepared to hold H1N1 clinics no later than the week of Nov. 16.

“Then,” said Mr. Poole, “the state contacted us and offered us as much H1N1 vaccine as we needed to conduct a public clinic to serve children six and up as well as the general public.

“Yesterday [Wednesday] we had a conference call with our DPH contact, and were assured that if we tell them we need 7,000 or 8,000 doses of H1N1 vaccine — and that’s a reasonable estimate of what we think we’ll need — they can provide us enough vaccine.”

Apparently, he said, the Island was chosen this way because state evaluations of previous clinics here were positive.

“They went to communities they knew could perform,” Mr. Poole said. “So we have the choice to jump the H1N1 line and go to the front.”

Yet there are doubts. Mr. Poole said he knew of other communities on the Cape which also had been approached to fast-track their flu clinics, and had declined.

“We’re trying to get comfortable with the idea that the state can deliver on its promise of enough vaccine so that we can schedule and publicize a clinic,” he said.

The state’s failure to deliver on vaccine — for the regular seasonal flu, not H1N1 — has twice caused the cancellation of two planned clinics on the Vineyard.

“Early on they told us to get our [seasonal flu] clinic done early, to clear our calendars for H1N1. So initially we scheduled for Sept. 26, but the state couldn’t deliver the vaccine to us. Then we pushed it to Oct. 24, and the same thing happened,” Mr. Poole said.

Until the state’s offer of H1N1 vaccine this week, the plan was to immunize people only against regular flu at the Nov. 11 clinic, which would have run from 8 a.m. to noon.

Now, however, it will be an all-day affair, likely dealing with children, mostly in the morning, and adults in the afternoon. The morning, Mr. Poole said, would mostly be doing H1N1 vaccinations, and the afternoon mostly seasonal flu.

The reason for it being structured that way is that with regular seasonal flu older people are at greater risk, and therefore the main target group for inoculation. But swine flu has proven to be a greater problem among the young.

Thus the Centers for Disease Control has nominated those between the ages of six months and 24 years as a target group, along with pregnant women, people who live with or care for children younger than six months of age, and people aged 25 through 64 who are at higher risk for H1N1 because of chronic health disorders or compromised immune systems.

Partly because of the size of the undertaking, and partly as a rehearsal for possible future emergencies on the Island, the clinic is planned to operate in a more complicated way this year.

Instead of simply driving directly to the high school for their shots, Islanders will be required to go first to one of two staging areas, at the Agricultural Hall in West Tisbury or Waban Park in Oak Bluffs, before being allowed to go to the school.

“If thousands of people all decide to turn up at the high school at the same time, it’s a problem, so the idea was to have staging areas where they could do screening and counseling, and govern the flow from those areas into the controlled area, the high school,” Mr. Poole said.

The staging plan only will apply to people in cars.

“People should know that if they take public transport, or walk, or bicycle, or go any way but by car, they can go straight to the high school,” Mr. Poole said.

As in previous years, those unable to walk to the school gymnasium for their vaccine will be offered a drive-through service.

All of this assumes the state comes through with the promised H1N1 vaccine. If it does not, the plan B to be negotiated between health agents and school authorities would involve vaccinating children at their schools.

And even if the state does come through, there are still some wrinkles to the plan. One is that children six months to nine years old will need two doses of H1N1 vaccine, separated by at least 21 days and preferably four weeks.

It is yet to be determined how that will be dealt with — the preferred option is a second, centralized clinic, but it will be up to parents to ensure their children get their second dose.