“You can do whatever you guys want,” he said in the video, “but I am pro-vaccine.”
Mr. Biden’s aides say he is open to taking questions from YouTubers and welcoming celebrities to the White House if it might help sway the unconvinced.
“There’s only so much we as a White House can do to stop misinformation,” Mr. Flaherty said. “What we can do is go on offense. That underscores exactly why this work is so important.”
Young people under the age of 27 are vaccinated at a lower rate than older people, according to the White House, and they were part of the reason the administration said it fell short of Mr. Biden’s goal of partly vaccinating 70 percent of adults by July 4. Younger people became eligible for immunization later in the vaccine rollout, after other high-priority risk groups, and children aged 12 to 15 became eligible for the Pfizer-BioNTech vaccine only in mid-May.
Across the country overall, providers were administering about 0.55 million doses per day on average, as of Wednesday, about an 84 percent decrease from the peak of 3.38 million reported on April 13.
The White House still faces significant challenges in reaching reluctant Americans, particularly in 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 and Tennessee’s top vaccination official, who said she was fired from her job after distributing a memo that suggested that some teenagers might be eligible for vaccinations without their parents’ consent. The memo repeated information that has been publicly available on the state Health Department’s website for years.
“We continue to see young people hit by the virus,” Ms. Psaki said, “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.”