President Joe Biden receives a COVID-19 booster shot during an event in the South Court Auditorium on the White House campus, Monday, Sept. 27, 2021, in Washington. Credit: Evan Vucci / AP

Tens of thousands of Mainers who received the Pfizer COVID-19 vaccine may be eligible for a booster in the coming weeks or months after federal regulators authorized another dose last week to provide an additional layer of protection for certain groups.

The booster recommendation comes as the virus continues to spread mostly among unvaccinated people, while vaccines continue to be effective in preventing severe illness and death due to COVID-19. But the U.S. Centers for Disease Control and Prevention concluded that a booster could benefit people who may have seen a slight decrease in immunity since they were first vaccinated.

Here is what you need to know about who is eligible and how to get a COVID-19 booster shot in Maine.

Who is eligible for booster vaccines?

The U.S. CDC has authorized a booster shot of the Pfizer vaccine for people 65 and older and those living in congregate care settings. People with underlying health conditions — including diabetes and chronic obstructive pulmonary disease — or working in frontline jobs, such as teachers, health care workers and grocery store employees, are also in authorized groups.

People who received two doses of the Pfizer vaccine are eligible for a third dose if it has been at least six months since they received their second shot. As of Monday, that would mean people who got their second shot on or before March 27. People who finished their Pfizer course after that will be eligible in the coming weeks or months.

What if I got Moderna or Johnson & Johnson?

Booster shots have not yet been approved for people who received the Moderna or Johnson & Johnson vaccines, but Surgeon General Vivek Murthy said during a briefing last week that he expects a recommendation in the coming weeks.

Where can I go for a booster shot in Maine?

Because the booster is the same formula and dosage as first and second Pfizer shots, boosters are available at most vaccination sites that are offering the Pfizer vaccine. Large chain pharmacies, including CVS and Walgreens, are already offering the booster shots at locations across Maine. You can make an appointment online or by calling your local pharmacy.

Northern Light Health, which had been taing walk-ins for vaccinations, is asking patients to make booster appointments online for its hospital and pharmacy-based clinics — which include locations in Bangor, Presque Isle and Pittsfield, among others — due to expected high demand. MaineHealth is also asking patients to schedule an appointment by calling 877-780-7545.

Do I need to bring my vaccine card?

Health care providers may ask for proof that it has been at least six months since your second Pfizer dose, though this may not be necessary if you are getting your booster at the same provider that administered your first two shots.

But if you have misplaced your vaccine card in the last six months, don’t worry too much. You can contact your primary care provider to obtain your vaccination records, or fill out a form online to get them through the Maine Immunization Information System.

How is a booster different from the ‘3rd shot’ for immunocompromised people?

Federal regulators previously authorized a third COVID-19 vaccine shot for severely immunocompromised people, such as cancer patients and organ transplant recipients, in late August. That shot aims to give some vaccine protection to people who — because of an underlying health condition — had little to no immune reaction to the first two doses.

A booster shot, on the other hand, is aimed at people who had a normal immune reaction to the first two doses but have seen their level of protection wane over time. Scientists have generally agreed that immunity may not be as long-lasting in older adults, with one study out of Israel finding a significant drop in COVID-19 cases among people over 60 who got the third shot. But there remains some dispute over whether boosters are really necessary for younger people, who may have longer-lasting protection from the original vaccine sequence.

Will boosters take away doses from people who have yet to get the vaccine?

No. The U.S. is no longer constrained in terms of supply of COVID-19 vaccines. Health officials still strongly encourage unvaccinated people to get the shot, and there are enough vaccines at this point to cover both new first doses for them and boosters for people who have already been vaccinated.

How many Mainers have already had boosters?

As of Sunday, the most recent data available, a bit more than 13,300 Mainers had already received either boosters or third doses, according to the state.