WASHINGTON (AP) — Vice President Mike Pence and the leaders of the House and Senate received their first doses of the COVID-19 vaccine on Friday as they tried to reassure the American public that the shot is safe. Pence, in a live-television event, celebrated the milestone as “a medical miracle” that could eventually put an end to a raging pandemic that has killed more than 310,000 people nationwide.

Conspicuously absent: President Donald Trump, who has remained largely out of sight five days into the largest vaccination campaign in the nation’s history.

“I didn’t feel a thing. Well done,” Pence told the technicians from Walter Reed National Military Medical Center on Friday morning as he became the highest-ranking U.S. official to receive the Pfizer-BioNTech shot, the first authorized in the U.S.

Later, House Speaker Nancy Pelosi, a Democrat, and Senate Majority Leader Mitch McConnell, a Republican, tweeted photos of themselves receiving the vaccine from the Capitol physician, who urged all members of Congress to join them.

The public displays come as top U.S. health officials are trying to persuade regular Americans who may be skeptical of the vaccinations to get them to pave the way for the end of the pandemic.

A recent survey from The Associated Press-NORC Center for Public Affairs Research found that only about half of Americans want to get the vaccine as soon as possible. Another quarter of the public isn’t sure, while the remaining quarter say they aren’t interested. Some simply oppose vaccines in general. Others are concerned that the injections have been rushed and want to see how the rollout goes.

Trump, who was hospitalized with COVID-19 in October, has been largely absent from the effort to sell the American public on what aides hope will be a key part of his legacy. He has held no public events to trumpet the rollout. He hasn't said when he will be inoculated. And he has tweeted fewer than a handful of times about the vaccines despite sending a flurry of tweets about other topics.

He did weigh in with a congratulatory tweet Friday night after the Food and Drug Administration authorized an emergency rollout of a second vaccine developed by Moderna Inc. and the National Institutes of Health.

Trump’s relative silence comes as he continues to rage about his defeat in the Nov. 3 election and embraces increasingly extreme efforts to overturn the people’s will. He’s pushed aside the plans of aides who wanted him to be the public face of the vaccination campaign, eschewing visits to labs and production facilities to thank workers, or hosting efforts to build public confidence in the shot, according to people familiar with the conversations who spoke on condition of anonymity to speak candidly.

Instead, Pence has been the one in the spotlight highlighting the safety and efficacy of the vaccines, touring a production facility this week before headlining Friday's event.

Pence didn’t flinch during the quick prick, nor did his wife, Karen. Surgeon General Jerome Adams, who is Black, also received a shot during the televised White House event and stressed the importance of communities of color seeing people like him being vaccinated to build trust.

“Today, Karen and I wanted to step forward and take this vaccine to assure the American people that while we cut red tape, we cut no corners," Pence said. “Hope is on the way."

Trump's lack of visibility has been surprising, especially for a president rarely shy to take credit, said Lawrence Gostin, a professor at Georgetown Law who focuses on public health.

“The president’s relatively low profile on the COVID response since the election is curious and counter to Mr. Trump’s own interests,” he said. Gostin, who has criticized Trump's handling of the pandemic in the past, said that he “deserves a great deal of credit" for Operation Warp Speed and placing a bet on two vaccines that use groundbreaking mRNA technology.

“Having exhibited leadership in the vaccines’ development, he should take great pride in publicly demonstrating his trust in COVID vaccines," he said.

Trump did appear at a White House “summit” ahead of the Food and Drug Administration's approval of the Pfizer vaccine last week. But many Trump aides are puzzled by his low profile now that the vaccine is actually being injected. They see it as a missed opportunity for the president, who leaves office on Jan. 20, to claim credit for helping oversee the speedy development and deployment of the vaccine that is expected to finally contain the virus.

Trump himself has fretted about credit going to his successor, Biden, who will preside over the bulk of the nationwide injection campaign next year.

“Don’t let Joe Biden take credit for the vaccines,” Trump has told reporters. “Don’t let him take credit for the vaccines because the vaccines were me, and I pushed people harder than they’ve ever been pushed before.”

In fact, FDA scientists were the ones who came up with the idea for Operation Warp Speed, the White House-backed effort through which millions of doses of coronavirus vaccines and treatments are being manufactured even as they are still being evaluated. And much of the groundwork for the shots was laid over the past decade, including through research on messenger RNA, or mRNA, used in the vaccines developed by both Pfizer and Moderna.

Trump's low-key approach could have an impact on public health. Dr. Anthony Fauci, the country's top infectious-disease expert, told NBC News this week that 75% to 85% of the nation needs to be vaccinated to achieve “herd immunity,” making the public education campaign about the vaccine’s safety all the more pressing.

Trump has said he would be open to taking a vaccine. White House deputy press secretary Brian Morgenstern told reporters that, because Trump already had COVID-19, his doctors have been trying to determine when he should take it.

“When the time is right, I’m sure he will remain willing to take it,” he said.

According to guidance from the Centers for Disease Control and Prevention, there is not yet enough information to determine whether those who have had COVID-19, like Trump, should get the vaccine.

But White House press secretary Kayleigh McEnany offered an alternate explanation. She told reporters this week that Trump, who has previously spread misinformation about other vaccines, “wants to send a parallel message which is, you know, our long-term care facility residents and our front-line workers are paramount in importance."

Gostin disagreed. ”It will be enormously damaging to public trust in the vaccine if President Trump isn’t visibly enthusiastic, including getting his shot on national television,” he argued. “It simply isn’t good enough to have Vice President Pence as a proxy."

Some lawmakers have said they are reluctant to be among the first to be vaccinated so they’re not seen as jumping the line. But others enthusiastically made appointments.

“Millions of Americans are waiting for shots, many of whom are workers on the front lines of this pandemic,” tweeted Democratic Rep. Don Beyer of Virginia, who was among those to receive one. “I am not more important than they are, but national leaders must lead by example.”