The Philadelphia suburbs are prepared to meet the state’s March 28 deadline to schedule coronavirus vaccinations for all eligible residents who want one. But it may be months before those shots actually get into the arms of the counties’ most vulnerable residents, officials said Monday.

Chester County expects it will take as long as three months to vaccinate all their residents in phase 1A, which includes people 65 and older and adults with high-risk conditions, while Montgomery County anticipates it could take up to five months. And these estimates, county officials say, do not allow for any appointments by people in lower-priority groups.

According to these counties’ estimates, which are based on the doses they’ve been told they will get from the state for the next four weeks, they will still be inoculating 1A residents on May 1, when President Joe Biden said he will direct states to make all adults eligible to get in line for a vaccine. So for most folks in the Philadelphia suburbs, the wait may be weeks or months past May 1 — which is less than seven weeks away — unless the region sees a significant increase in vaccine supply.

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The region could get that boost from other initiatives. In the coming weeks, Delaware County may get thousands of more vaccine doses through a federal program, and the counties were set to learn more Tuesday about regional vaccination clinics that Pennsylvania plans to run using part of its share of the Johnson & Johnson one-shot vaccine. (The state is set to get 200,000 doses per week starting March 28.) The region’s Republican and Democratic members of the Pennsylvania legislature, which returned to session Monday, have also vowed to push for what they would see as a more geographically equitable rollout.

County leaders and lawmakers in Southeastern Pennsylvania have for weeks been asking the commonwealth for a boost in doses that accounts for the area’s population and its residents’ demand for vaccine. Inquirer data analyses, which the state has said it does not dispute, show that the region has received fewer doses per capita than any other in the commonwealth.

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The issue has put the region’s officials and legislators at odds with the Wolf administration, which over the past week has sent mixed messages about whether the region has been shortchanged and has not promised any fixes. State officials say southeastern county residents are vaccinated at or above the state average but haven’t said how far people are traveling to find vaccine doses.

A day after Biden’s optimistic speech, Gov. Tom Wolf on Friday said he, too, was confident that Pennsylvania was “within striking distance of the finish line” and announced the state’s new directive to providers — that they schedule appointments for everyone in 1A by March 28. By the end of March, the entire nation would be getting 22 million doses a week, more than four times what was being sent out in mid-January, he said, and Pennsylvania could give all 4.5 million residents in its 1A population a chance to be vaccinated by May 1. Officials estimate about 80% of them will want to get shots.

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It remained unclear Monday how the state will ensure people in 1A can get appointments in less than two weeks, but Wolf said Friday the state would give providers more advanced notice of their weekly dose allotments to help them schedule patients farther in advance. Currently, providers learn of their weekly allocation at the end of the previous week.

But officials in Chester and Montgomery Counties said, at least for the next month, they won’t be seeing the upticks they need to meet the governor’s goal.

Chester County officials reached out to the state over the weekend, they said, to ask for “significantly more doses” on their weekly vaccine request form to get through 1A by the end of April. They said they were told they’d receive 4,340 first doses per week for the next three to four weeks, which is in line with previous weeks’ allocations.

» READ MORE: ‘What is the plan?’ Suburban Pa. officials blast Dept. of Health over region’s vaccine supply as dispute intensifies

Montgomery County officials said they have been told that for the next four weeks, they will receive 5,850 first doses, a slight increase from the 4,680 the county Office of Public Health got last week.

In Bucks and Delaware Counties, officials said they had not heard Monday about vaccine allotments for the coming weeks. Without that number, Delaware County Council Vice Chair Monica Taylor said it is difficult to gauge how long the 1A rollout will take.

“It all depends on how much we actually get,” Taylor said. If her county also doesn’t see an increase, “it’s going to take several months.”

The Department of Health said by Friday all providers will receive formal notice of their allotment for next week, and “what providers receive as their allocation for the week of March 22 is roughly the high-volume they can expect for the next month.”

“In anticipation of this, we ask the high-volume providers to start scheduling appointments through April,” a spokesperson said. “This will meet both goals of scheduling the appointments and vaccinating people in 1A as quickly as possible.”