Elvis and Nixon. Trump and Kanye. Biden and Olivia.
On Wednesday, the pop star Olivia Rodrigo visited the White House, joining the Biden administration’s continuing effort to enlist the young and famous to reach the young and unvaccinated.
Ms. Rodrigo, 18, has the No. 1 album in the country with her debut, “Sour.” But more important — to the White House, at least — she has millions of followers on social media. She planned to spend the afternoon on Wednesday filming videos with President Biden and Dr. Anthony S. Fauci that will encourage young Americans to receive a coronavirus vaccination shot if they had not done so already.
In recent weeks, as the federal strategy has shifted to more personalized efforts to reach people who have not gotten shots, the administration has recruited YouTube stars, assorted social media influencers and celebrities who can send the messages directly to their own channels. It has also highlighted efforts by popular dating apps to encourage young singles to promote their vaccination status.
Healthy young adults — or “young invincibles” — are historically hard to reach, and the White House has been upfront about the difficulties that officials have faced in convincing them to receive a vaccine. Those hurdles can include an overlapping mix of inertia, fear, busy schedules and misinformation.
Young people under the age of 27 are vaccinated at a lower rate than older people, according to the White House, and were part of the reason the administration said it fell short of reaching Mr. Biden’s goal of vaccinating 70 percent of Americans by July 4. Younger people became eligible for immunization later in the vaccine rollout after other high-priority risk groups. Those aged 12 to 15 only became eligible for the Pfizer-BioNTech vaccine in mid-May.
Across the country, as of Tuesday, providers were administering about 530,000 doses a day on average, about a 84 percent decrease from the peak of 3.38 million reported on April 13.
Ms. Rodrigo briefly took the White House lectern during her visit to speak to reporters.
“I’m in awe of the work President Biden and Dr. Fauci have done,” Ms. Rodrigo said, reading from a list of prepared remarks, “and was happy to help lend my support to this important initiative.”
“Not every 18 year old uses their time to come do this,” the White House press secretary, Jen Psaki, said later.
The White House is still facing significant barriers to reaching reluctant Americans, particularly in conservative states where officials say they face pressure against evangelizing for a vaccine.
After Ms. Rodrigo left the podium, Ms. Psaki was asked about Dr. Michelle Fiscus, a pediatrician who was Tennessee’s top vaccination official until recently.
Dr. Fiscus has said she was fired from her job after she distributed a memo that suggested some teenagers might be eligible for vaccinations without their parents’ consent. The memo repeated information that had been publicly available on the health department’s website for years.
“And we’ve been crystal clear that we stand against any effort that would politicize our country’s pandemic response and recovery from Covid-19,” Ms. Psaki said.