NEW YORK (NewsNation Now) — The largest vaccination campaign in United States history rolled out Monday as the nation’s death toll from COVID-19 neared 300,000.

New York administered its first vaccine to an intensive care unit (ICU) nurse early Monday. Gov. Andrew Cuomo livestreamed the event from Long Island Jewish Medical Center in Queens.

“It didn’t feel any different from taking any other vaccine,” nurse Sandra Lindsay said after getting a shot in the arm.

“I feel hopeful today, relieved,” Lindsay said. “I feel like healing is coming. I hope this marks the beginning of the end of a very painful time in our history. I want to instill public confidence that the vaccine is safe.”

President Donald Trump tweeted after the event, “First Vaccine Administered. Congratulations USA! Congratulations WORLD!”

During the news conference, Cuomo said he wasn’t sure if the nurse was the first person in the country to receive the vaccine.

The historic news comes just as the United States reached 300,000 COVID-19 deaths.

Dr. Deborah Birx, the White House Coronavirus Task Force coordinator, calling it an exciting day to see science translated from bench to bedside and a smart move to have healthcare workers go first.  

“They’re working tirelessly,” said Dr. Birx. “They’ll be taking the vaccine first, everybody will see that there’s no substantial long-term consequences to that vaccination. And then getting it to the long-term care providers.”

Meanwhile, frozen vials of Pfizer’s COVID-19 vaccine are arriving at hospitals across the U.S.

“It feels like the cavalry is arriving,” Robert C. Garrett, CEO of Hackensack Meridian Health, said as New Jersey’s largest health network awaited delivery.

Shots made by Pfizer Inc. and its German partner BioNTech are the first authorized for emergency use by the Food and Drug Administration — beginning what will become the largest vaccination campaign in U.S. history. Several other countries also have OK’d the vaccine, including the U.K., which started vaccinating last week.

For health care workers who, along with nursing home residents, will be first in line for vaccination, hope is tempered by grief and the sheer exhaustion of months spent battling a coronavirus that still is surging in the U.S. and around the world.

“This is mile 24 of a marathon. People are fatigued. But we also recognize that this end is in sight,” said Dr. Chris Dale of Swedish Health Services in Seattle.

Packed in dry ice to stay at ultra-frozen temperatures, the first of nearly 3 million doses being shipped in staggered batches this week made their way by truck and by plane around the country Sunday from Pfizer’s Kalamazoo, Michigan, factory. Once they arrive at distribution centers, each state directs where the doses go next.

Some hospitals across the country spent the weekend tracking their packages, refreshing FedEx and UPS websites for clues.

More of the Pfizer-BioNTech vaccine will arrive each week. And later this week, the FDA will decide whether to greenlight the world’s second rigorously studied COVID-19 vaccine, made by Moderna Inc.

Now the hurdle is to rapidly get the vaccine into the arms of millions, not just doctors and nurses but other at-risk health workers such as janitors and food handlers — and then deliver a second dose three weeks later.

“We’re also in the middle of a surge, and it’s the holidays, and our health care workers have been working at an extraordinary pace,” said Sue Mashni, chief pharmacy officer at Mount Sinai Health System in New York City.

Plus, the shots can cause temporary fever, fatigue and aches as they rev up people’s immune systems, forcing hospitals to stagger employee vaccinations.

The FDA, considered the world’s most strict medical regulator, said the Pfizer-BioNTech vaccine appears safe and strongly protective — and laid out the data behind it in a daylong public meeting last week for scientists and consumers alike to see.

“Please people, when you look back in a year and you say to yourself, ‘Did I do the right thing?’ I hope you’ll be able to say, ‘Yes, because I looked at the evidence,’” Dr. Francis Collins, director of the National Institutes of Health, said Sunday on NBC’s Meet the Press. “People are dying right now. How could you possibly say, ‘Let’s wait and see.’”

Still, emergency use means the vaccine was cleared for widespread use before a final study in nearly 44,000 people is complete — and that research is continuing to try to answer additional questions. While effective against COVID-19 illness, it’s not yet clear if vaccination will stop the symptomless spread that accounts for half of all cases.

The shots still must be studied in children, and during pregnancy. But the American College of Obstetricians and Gynecologists said late Sunday that vaccination should not be withheld from pregnant women who otherwise would qualify.

While the vaccine was determined to be safe, regulators in the U.K. are investigating several severe allergic reactions. The FDA’s instructions tell providers not to give it to those with a known history of severe allergic reactions to any of its ingredients.

On Monday morning, the U.S. Department of Health and Human Services (HHS) and the Department of Defense (DoD) will hold a briefing with senior officials on Operation Warp Speed and COVID-19 vaccine distribution. You can watch that video in the player below: