Front-line medical workers in Maine who received the state’s first vaccinations against COVID-19 are due to get their second doses starting Tuesday, and Danielle Poulin is looking forward to it.

Poulin was among the first to be vaccinated at Maine Medical Center in Portland. A registered nurse who recently became a nurse practitioner, Poulin works in the intensive care unit and has cared for patients who had COVID-19.

She was inoculated Dec. 15 with the Pfizer vaccine, which requires a booster shot three weeks later to be 95 percent effective in protecting the recipient, according to clinical trials.

On Tuesday, Poulin is ready to roll up her sleeve again.

“I’m scheduled to get my second dose on the 5th,” she said. “I’m working during the day, and I’ll get it during my shift, when someone will cover for me.”

Poulin, who felt only mild soreness near the injection site with the first shot, said she expects the booster will build on the relief that she and her co-workers felt with the initial dose after facing the coronavirus threat for nine months.

“I think everyone feels more comfortable with just the one shot,” said Poulin, 31. “So with the second shot, it will be even better.”

As of last week, the federal government was still assuring state officials that booster doses were on the way, amid reports of vaccine shipment shortfalls and a surging pandemic that by Sunday had killed at least 359 people in Maine and more than 351,000 nationwide.

Maine Med is confident it will have enough doses to start administering booster shots this week.

“We have the booster doses of Pfizer on hand,” said Matt Wickenheiser, a Maine Med spokesman. “We are not anticipating any issues with second dosing overall.”

Northern Light Health, which includes Eastern Maine Medical Center in Bangor, also expects to administer booster doses in the coming days to staff members who were vaccinated in the first round.

“We know the doses have been set aside for this purpose and our supply should arrive in the next few days,” said Suzanne Spruce, Northern Light spokeswoman.

Michelle Burke, another health care worker who was among the first to receive her shot, was scheduled for her second dose Sunday morning.

“The first dose was totally fine,” she said Saturday afternoon. “I had no side effects at all.”

Burke is an ER nurse at Maine Med, and spends a significant portion of her shifts in the isolation unit with COVID-19 patients, wearing a respirator and other heavy-duty protective equipment. After receiving her first dose last month, Burke said she was grateful for the added protection, but wanted to continue to serve as an example for the wider population by following safety measures such as mask-wearing and social distancing.

Now, as case numbers surge across Maine, health workers like Burke are seeing the effects in their daily lives. On Saturday, Burke said that some recent COVID-19 patients were telling hospital workers that they had attended holiday gatherings, in some cases traveling across state lines to do so.

“The least we can do is follow the CDC recommendations and not attend large gatherings and not travel unless we absolutely have to,” Burke said.

Burke said she recognized that many people are tired of the pandemic’s long-term disruption to their lives. But she asked Mainers to hold in there a bit longer.

“People are ready to get back to normal,” she said. “It’s hard not to get fed up with it – I understand that – but it’s going to take a little while.”

The Maine Center for Disease Control and Prevention announced Thursday that it had placed its fifth order for doses of COVID-19 vaccines, enough to inoculate an additional 17,075 people.

The order, which is expected to arrive early this week, will comprise 8,775 doses from Pfizer and 8,300 doses of the Moderna vaccine for the state’s fourth week of distribution. The total number is less than the third week’s allocation of 19,125, according to the Maine CDC.

Also this week, hospitals are expected to receive the second dose of the Pfizer vaccine for individuals who were inoculated during the first week of distribution, including Poulin.

Combined with previous orders, Maine expects to have enough to vaccinate approximately 81,850 people in the first four weeks of distribution, the Maine CDC reported.

As of Sunday morning, Maine had administered first doses of COVID-19 vaccine to at least 32,995 health care workers and nursing home residents, according to the state’s vaccine information website. The Moderna vaccine also requires a booster shot within a few weeks.

Although Maine has received less vaccine than expected, the anticipated arrival of additional doses will allow the state to expand its inoculation effort to medical personnel outside hospitals who have been providing direct patient care, said Jeanne Lambrew, head of the Maine Department of Health and Human Services.

Dr. Nirav Shah, director of the Maine CDC, said fluctuating vaccine deliveries have forced the agency to alter the state’s vaccination planning, which generally aligns with recommendations of the U.S. CDC’s Advisory Committee on Immunization Practices.

So far, Maine has prioritized its limited supply of vaccine for medical personnel and residents of skilled nursing and long-term care facilities under Phase 1a of the state’s COVID-19 interim draft vaccination plan.

Maine has begun to extend vaccination beyond hospital staff to other health care workers in Phase 1a. The goal, recognizing that Maine’s planning is dependent on the federal government’s vaccine allocation, is to provide vaccine by February to all health care personnel and long-term care residents in Phase 1a, the Maine CDC said.

In the fourth week of distribution, the Maine CDC is targeting 17,075 doses of vaccine to hospitals (7,000), outpatient groups (2,500), emergency medical services (200), independent pharmacies serving skilled nursing facilities (2,500) and the retail pharmacy long-term care program (4,875).

Over half of this week’s allocation is targeted toward staff at hospital-affiliated medical practices that provide direct patient care, dialysis centers, oncology practices, federally qualified health centers and independent medical practices that provide urgent and acute care, the Maine CDC said.

Staff Writer Rob Wolfe contributed to this report.