Federal health officials said Friday that more than 100 million people in the United States had been fully vaccinated against the coronavirus, a milestone that represents almost 40 percent of the nation’s adults. But concern continues to build among health officials over reaching more people who have not received shots.
The 100 million mark is almost double what the nation had registered at the end of March. The federal government also shipped its 300 millionth dose this week, according to Jeffrey D. Zients, the White House’s Covid-19 response coordinator.
The Biden administration is beginning a critical stage of its vaccination campaign that requires finding ways to inoculate those who remain hesitant or skeptical, or have had trouble accessing a vaccine. Officials repeatedly emphasized at a White House news conference on Friday that the “next phase,” as Mr. Zients referred to it, called for targeted, local and personalized efforts. President Biden recently called on employers to give workers paid time off to get vaccinated.
Polls have shown resistance to the vaccine is more deeply rooted among white people who live in rural areas, especially those who vote Republican, or describe themselves as evangelical Christians. Campaigns aimed at Black and Latino communities have made striking gains, though public health experts have said obstacles to access deserve much of the blame for disparities seen in their vaccination rates.
As of Friday, providers were administering about 2.55 million doses per day on average, about a 25 percent decrease from the peak of 3.38 million reported on April 13, according to data from the Centers for Disease Control and Prevention. And some regions of the country — particularly the South — were lagging well behind others.
The reasons for the decline in the pace are still not entirely clear. Mr. Zients acknowledged that the overall number of daily vaccinations would now “moderate and fluctuate,” and that there would be “more of a balance between supply and demand.” Nearly 30 million doses were shipped this week.
Signs of possible dips in demand have led some public health experts to fear a general plateauing of interest.
“This is one of these all hands on deck moments, when each of us needs to look around in our communities and our families and our circle of friends, and ask people if they have a plan to get vaccinated,” Dr. Vivek Murthy, the surgeon general, said on Friday.
To continue the momentum of the campaign, officials said the government was working to make it easier for Americans to get inoculated at doctors’ offices and at walk-up sites without an appointment.
“We know that around 80 percent of people who are trying to decide about a vaccine say that they want to talk to their doctor about that decision. And we’ve heard that loud and clear,” Dr. Murthy said, adding that the Biden administration would say more soon about efforts to get vaccines to people through their physicians.
Mr. Zients said 90 percent of doctors had received at least one dose, pointing to the statistic as a way to help reassure people about vaccines.
Dr. Murthy said the government was also working with social media companies to eliminate misinformation about the vaccines. Later on Friday, Jen Psaki, the White House press secretary, said that the Biden administration’s approach to counteracting vaccine misinformation is to “provide and flood the zone with accurate information” and that it will invest $3 billion in public campaigns to that end.
“I think that they have work to do,” Dr. Murthy said. “We still have way too much disinformation spreading on those sites. And it presents a clear and present danger, I believe, to people who need to be protected from Covid and who could potentially get vaccinated.”
Linda Qiu contributed reporting.