WASHINGTON (AP) — Vice President Mike Pence became the highest ranking U.S. official to receive the first dose of the COVID-19 vaccine on Friday in a live-television event aimed at reassuring Americans the shot is safe. He celebrated the milestone as "a medical miracle" that could eventually contain the raging pandemic.

Conspicuously missing from the victory lap: President Donald Trump, who has remained largely out of sight five days into the largest vaccination campaign in the nation's history.

Pence, meanwhile, has taken an increasingly visible role in highlighting the safety and efficacy of the shots, including touring a vaccine production facility this week. House Speaker Nancy Pelosi and Senate Majority Leader Mitch McConnell both said Thursday that they will get vaccinated in the next few days. President-elect Joe Biden expects to receive his shot as soon as next week.

"I didn't feel a thing. Well done," Pence told the technicians from Walter Reed National Military Medical Center who administered his Pfizer-BioNTech shot early Friday morning. Pence didn't flinch during the quick prick, nor did his wife, Karen, or Surgeon General Jerome Adams, who also received shots during the televised White House event in the Eisenhower Executive Office Building.

"Hope is on the way," Pence later said. "The American people can be confident: We have one and perhaps within hours two safe vaccines," he added, referring to the FDA's expected authorization of a second vaccine by Moderna.

He did not respond to shouted questions about why the president wasn't headlining a similar event.

Adams, who is Black, emphasized the "the importance of representation" in outreach to at-risk communities and encouraged Americans to avoid disinformation around the vaccines.

Five days into the largest vaccination campaign in the nation's history, Trump 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 been inoculated himself. And he has tweeted fewer than a handful of times about the shot.

Trump's relative silence comes as he continues to stew 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.

The sheepish approach 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. That event included an introductory video highlighting the past comments of those — including top government infectious-disease expert Dr. Anthony Fauci — who doubted a shot would be ready this year.

Trump "will continue to update the country through a variety of means while giving medical professionals and hardworking staff at OWS the space to do their jobs and save lives," said White House deputy press secretary Brian Morgenstern.

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 at noon 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 that has killed more than 310,000 Americans.

Trump himself has tried to minimize any credit that might go 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."

Despite Trump's claims, 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. Pfizer developed its vaccine outside Operation Warp Speed but is partnering with the federal government on manufacturing and distribution.

Trump's low-key approach could have an impact on public health. Dr. Anthony Fauci, the nation'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.

A 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 yet to indicate when or if he will receive the shot.

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. Still, Fauci recommended that Trump take it publicly without delay.

"Even though the president himself was infected, and he has, likely, antibodies that likely would be protective, we're not sure how long that protection lasts. So, to be doubly sure, I would recommend that he get vaccinated as well as the vice president," Fauci told ABC News.

White House press secretary Kayleigh McEnany 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," she said.

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."