They have witnessed the worst that COVID-19 can do, seen patients struggle to breathe on ventilators and watched helplessly as some of them died while isolated from family and friends. They have worked endless hours, putting themselves at risk, and worried about co-workers who have fallen ill.

And on Tuesday morning, front-line health care workers at Maine Medical Center eagerly rolled up their sleeves and became the first Mainers to receive Pfizer’s COVID-19 vaccine. They did so with a mixture of hope and gratitude amid a global pandemic that has killed 265 people in Maine, over 301,000 nationwide and 1.62 million across the world.

“I’m glad to be part of the solution and help make the community safer for everyone,” said Kayla Mitchell, 31, of Scarborough, a registered nurse who works in Maine Med’s intensive care unit.

Mitchell was the first person in Maine to receive the vaccine, beginning a statewide inoculation effort that’s expected to take several months and possibly require people to wear masks into 2022. The Pfizer vaccine requires two doses. Mitchell will receive a booster shot in a few weeks.

Mitchell said she’s confident the vaccine is safe and effective, especially when compared to the anguish she has witnessed among COVID-19 patients she has cared for in the ICU and their families.

“I trust the science and I trust that receiving the vaccine is a safer alternative to how critically ill patients are suffering,” Mitchell said, her voice trembling with emotion. “I’ve seen enough. People are scared and they end up alone. It’s exhausting and it’s relentless.”

Maine Med, part of the MaineHealth group, received 975 doses of the Pfizer vaccine that were delivered to the hospital in Portland around 7:30 a.m. Tuesday. They were placed in an ultra-cold freezer in the hospital’s secure pharmacy department because the vaccine must be kept at minus 70 degrees Celsius (minus 94 degrees Fahrenheit).

MaineHealth is expected to receive a total initial allotment of nearly 1,900 doses of the Pfizer vaccine this week, including 900 reallocated from deliveries to other Maine hospitals. With the anticipated approval of the Moderna vaccine later this week, MaineHealth expects to get an additional 15,775 doses next week.

Overall, the Maine Center for Disease Control and Prevention expects to receive 74,875 vaccine doses in the first three weeks of the rollout, including the two-dose Moderna vaccine. The two vaccines are not interchangeable, so second doses must be from of the same vaccine, according to federal guidelines.

Christina DeMatteo, a hospitalist and infectious disease physician at Maine Medical Center, prepares to administer the vaccinne to a hospital staff member. Derek Davis/Staff Photographer

The first inoculation clinics are being offered to health care workers who have direct patient contact and residents of nursing homes, groups that number about 75,000 and 6,200, respectively.

Elderly Mainers and other high-risk groups will follow in the months ahead, with the general public likely being offered the vaccine next summer. Federal guidelines warn of precautions or contraindications for people with a severe allergic reaction to injected therapies or any component of the Pfizer vaccine.

MaineHealth planned to vaccinate about 150 people on Tuesday, including ICU staff members at Southern Maine Medical Center in Biddeford. No adverse reactions were reported as of Tuesday afternoon.

The inoculation of ICU, emergency department and COVID unit personnel will expand on Wednesday, when MaineHealth is expected to begin vaccinating staff at Mid Coast Hospital in Brunswick as well.

“We should be vaccinating several hundred people per day by Thursday,” said Dr. Dora Anne Mills, MaineHealth’s chief health improvement officer.

In the Northern Light Health group, Mercy Hospital in Portland and Eastern Maine Medical Center in Bangor each received 975 doses on Monday and planned to start inoculating staff members on Wednesday morning.

Central Maine Medical Center in Lewiston received 975 doses Tuesday, nearly half of which will be administered to front-line staff across the Central Maine Healthcare system, and it shared 500 doses with St. Mary’s Regional Medical Center, also in Lewiston. Initial doses also were delivered Tuesday to Maine General in Augusta and AR Gould Hospital in Presque Isle.

As vaccine distribution gets underway, the virus is surging in Maine and elsewhere. Maine reported 411 new COVID-19 cases Tuesday, marking the sixth time the state has recorded more than 400 cases in a single day. Still, many are hopeful that the introduction of the vaccine spells the beginning of the end.

“This is such a historic day for Maine,” Mills said. “Here we are, in the darkest days of December, in the midst of a deadly surging pandemic, when COVID-19 has become the No. 1 cause of death in the country, and we are taking part in what I believe is the biggest public health and scientific success of our lifetimes.”

Danielle Poulin, a registered nurse who works in Maine Med’s COVID ICU, was second in line Tuesday at MaineHealth’s first vaccination clinic.

“I’ve personally witnessed what this virus can do to people and their families and I want to protect myself and others,” Poulin said. “I want to encourage others to get vaccinated, too, so we can end this pandemic.”

Poulin, who lives in Monmouth, said she was eager to be inoculated because vaccines are a common and time-tested form of disease prevention. Moreover, she said, the clinical trials for the first COVID-19 vaccines back up their safety and effectiveness. And she’s not worried about temporary symptoms that may result from being vaccinated, such as fever, headache and muscle pain.

Danielle Poulin, a registered nurse in Maine Medical Center’s COVD ICU department, watches as Dr. Christina DeMatteo draws the coronavirus vaccine into a syringe. Ben McCanna/Staff Photographer

“It’s not a live vaccine, so I know I’m not going to get COVID from being vaccinated,” Poulin said. “Any symptoms would mean my immune system is responding, and they’re mild compared to getting COVID.”

For Dr. Nate Mick, vice chairman of Maine Med’s emergency department, his aversion to needles couldn’t keep him from getting vaccinated Tuesday.

“It’s been a long nine months,” Mick said. “Like most of us who are on the front lines and seeing what COVID can do, we have no hesitation. We’re running towards this. This is a sign of hope and hope is in short supply these days.”

Mick, who lives in Falmouth, understands why some people might be reluctant get the vaccine, especially in light of the political and scientific debate that its rapid development has generated through the last several months.

“Until COVID touches you, whether through personal or professional experience, it can seem somewhat abstract,” Mick said. “It makes this a risk-benefit decision. Individuals have to weigh the risk. The technology behind the COVID vaccines is not new. Quite honestly, vaccine science has been the biggest source of medical advancement in recent years.”

Michelle Burke, a registered nurse in Maine Med’s emergency department, said she wanted to be vaccinated as soon as possible because it’s the first proactive thing she’s been able to do since the pandemic started. She also wanted to show others that the vaccine is safe.

Michelle Burke, a nurse in the hospital’s emergency department, smiles and pulls down her sleeve after receiving the vaccine. Derek Davis/Staff Photographer

“We’ve been so reactive, dealing with what’s coming at us,” said Burke, who lives in Portland. “This is something I can do ahead of time for myself and my husband and my patients. This is something we all can do.”

Dr. Christina DeMatteo, a specialist in infectious diseases and preventive medicine, volunteered to inoculate Maine Med’s front-line staff members Tuesday morning. She hopes the wider public takes advantage of the vaccine as soon as possible to ensure it’s effective. The lives of health care workers who’ve been battling COVID-19 are at stake.

“The hope and relief I’ve seen in staff today is palpable,” said DeMatteo, who lives in South Portland. “We all have friends and family members who are sick. This vaccine will save lives and the more people who get it, the more effective it will be. This could be the beginning of the end of COVID.”