Lynn Cummings receives the first dose of the Moderna vaccine at a newly-opened COVID-19 vaccination clinic on Wednesday, March 17, 2021, in Auburn, Maine. Credit: Robert F. Bukaty / AP

Providers allowing younger Mainers to book COVID-19 vaccine appointments before they become eligible on Wednesday have seen a crush of demand as corporate pharmacies hold the line until the general population is allowed to get shots.

Gov. Janet Mills announced last week that everyone over the age of 16 will be eligible as virus cases increased in Maine and the U.S. and appointments were left unfilled after the last eligibility change. This move will open up vaccines to anyone over 16 and it led to a rush in vaccine interest similar to what characterized the early days of vaccination in Maine.

Maine’s two biggest hospital systems reported that thousands signed up for appointments for Wednesday and later on the heels of the governor’s announcement, although one still had availability as of Monday afternoon. Those providers said the increase in the vaccine supply has not taxed their resources, while other providers are waiting for Wednesday to allow younger Mainers to book appointments.

Portland-based MaineHealth booked appointments for everyone over age 50 who are now eligible and had pre-registered as of Thursday. It scheduled 10,000 for those more under age 50 by Monday. The provider still has 37,000 people waiting, said spokesperson John Porter.

MaineHealth has consistently said it can handle more vaccines than it receives. Porter said an allocation of 31,000 vaccines a week might cause the provider to have to step up its operations, but this week it is getting 12,000 and it has more sites and personnel than it needs.

“It doesn’t change things at all from an operational standpoint,” said Porter, referring to the eligibility expansion.

Aside from increasing slots, Bangor-based Northern Light Health will also not be changing its operations. Affiliated physicians may be given vaccines if the state sees an increase in the one-shot Johnson & Johnson vaccine, said spokesperson Suzanne Spruce.

Northern Light saw more than 9,000 people register for Saturday appointments after Mills’ announcement, Spruce said. The provider does not keep a waitlist, but demand appeared to be similarly high on Monday when the system’s website allowed scheduling at 2 p.m., with more than 7,000 people waiting in line for appointments at sites from Portland to Presque Isle.

Slots for this week were largely filled as of 5 p.m. Monday, but dozens of appointments were available for next week at many of Northern Light Health’s seven clinics, including its massive operation at the Cross Insurance Center in Bangor, according to its website.

Providers like Hannaford, Walmart, Walgreens and CVS are receiving about 38 percent of 88,000 total doses coming into Maine as part of a record share of vaccines this week. But Maine’s federal pharmacy partners appeared to be waiting until Wednesday to open eligibility.

Those providers did not allow people under the age of 50 to schedule appointments on Monday. In CVS’ case, an online map indicated the pharmacy chain did not have vaccines. Spokespeople for Hannaford and Walgreens said the company would open up eligibility in line with the state on Wednesday.