The White House on Wednesday announced plans to distribute vaccines to a huge group that has been ineligible so far to receive the coronavirus shots — 28 million children aged 5 to 11. The operation is slated to begin as soon as federal health officials sign off on a reduced dose of the Pfizer-BioNTech vaccine, which the Biden administration anticipates could come as soon as the first week of November.

White House officials said they have already acquired enough doses to vaccinate every child in that age group. They plan to make the specially packaged vaccine available at more than 25,000 pediatricians’ and doctors’ offices, hospitals, pharmacies, community health centers, and school- and community-based clinics. They also will undertake a campaign to educate parents more fully about the vaccines.

That strategy is key to reducing the impact of the virus across the United States, Anthony S. Fauci, the nation’s top infectious-disease specialist, said at a White House briefing. The delta variant has changed the game, he said, describing a recent study showing children are getting infected and transmitting the virus as readily as adults, even though 50 percent of them are asymptomatic.

“If we can get the overwhelming majority of those 28 million children vaccinated, I think that would play a major role in diminishing the spread of infection in the community,” Fauci said. “That’s one of the reasons why we want to do as best as we can to get those children 5 to 11 vaccinated.”

The rollout will rely on familiar approaches, such as identifying trusted messengers to overcome vaccine hesitancy. But this one will be tailored to children and families, officials said. Among the changes will be a focus on administering the vaccines in small-group settings and the creation of a Parent Leadership Corps of scientists and other experts who are parents themselves, and who will be a resource for other parents.

Wednesday’s announcement comes as the Biden administration has struggled to regain confidence in its planning and coordination in the wake of its mid-August announcement that all Americans would be eligible for booster shots beginning in late September. The Food and Drug Administration and the Centers for Disease Control and Prevention narrowed the ranks of those eligible for booster shots, sowing confusion among some patients and practitioners.

On Wednesday, members of the White House response team compared their readiness for a pediatric vaccine rollout to what they described as the lack of coordination around the initial vaccine distribution effort last December, rather than as an end-run around federal regulators and health officials.

“I think we learned that lesson from the previous administration,” said Jeff Zients, the White House coronavirus response coordinator.

“Should the FDA and CDC authorize the vaccine, we will be ready to get shots in arms,” Zients said. “Kids have different needs than adults.”

An expert group advising the FDA is scheduled to meet Oct. 26 to hear data about the vaccine’s safety and efficacy and make recommendations to regulators. The FDA will then decide whether to authorize its use. If the FDA gives its assent, a vaccine advisory panel to the CDC is scheduled to meet Nov. 2 and 3 to weigh a recommendation for use. If the CDC director signs off on a recommendation, the vaccine may be administered to kids in early November.

White House officials said they are already hosting “operational readiness calls” with local jurisdictions and others, and stressing the need to distribute the shots to smaller, more intimate settings like doctors’ offices, rather than the mass-vaccination sites opened for adults last spring.

Lee Savio Beers, president of the American Academy of Pediatrics and a practicing pediatrician, praised the planning for “leaning heavily on the relationship that pediatricians have with families.”

She said the pediatricians’ group has been developing strategies to speak with parents about vaccination, some of them posted online. The group is also figuring out how to work effectively with school and church leaders. “We are thinking about how we leverage their expertise,” she said.

Pediatricians like Reshma Chugani, part of a two-doctor practice in Atlanta, are already making their own preparations.

Chugani said an office manager is already calculating how many 5-to-11-year-olds are among their patients and assuming that as many as a half will be signed up for shots. Given the minimum order of 300 doses, she said the practice may organize a weekend clinic to vaccinate as many children as possible “early on, as there will be initial demand that will then likely taper off.”

That pattern of brisk initial demand followed by slowed interest occurred among adolescents and teens, she noted. “Some families have been eager to vaccinate, while others are reluctant,” Chugani said in an email. “I have had countless conversations daily with parents and patients about the safety and efficacy of the vaccine and have had to counter misinformation on a daily basis. I anticipate that I will still be doing this with the younger age group moving forward.”

Other pediatricians are warning patients of limited initial supply. “This immunization will require a particular formulation that will not be available in large quantities immediately,” according to a notice a Boulder, Colo., practice sent to patients. “. . . We will add as many patients as possible to our schedule, but these appointments will be limited and not available until after approval is finalized. We recommend using other vaccination sites to access the vaccine quickly.”

Zients said a total of 15 million doses will be available in the first week after the vaccine is cleared for use. Of those doses, 10 million will be sent to local jurisdictions, 5 million to pharmacies and 265,000 to federal entities, such as the Indian Health Service, according to a CDC planning document sent to local jurisdictions last week, a copy of which was obtained by The Washington Post.

The federal government plans to allocate the initial shots according to a formula to ensure equitable distribution based on a state’s population of eligible children, according to state and federal health officials.

This vaccine will be shipped in smaller packages than the adult version — 10-dose vials in cartons of 10 vials each — along with smaller needles that would make more sense for pediatricians and community clinics to use, according to a federal planning guide. Once a vial is opened, doses must be used within six hours, the documents state.

It will be up to state officials to decide how to spread out the initial doses. In Maine, officials are giving priority to providers who plan vaccine clinics in the first week after the vaccine is authorized and recommended, said Nirav Shah, director of Maine’s Center for Disease Control and Prevention.

Shah said officials don’t expect all families to rush in for shots the first week. Survey data suggests about 30 to 35 percent of parents will want their children vaccinated immediately, he said.

Jay A. Winsten, director of strategic media initiatives at the Harvard School of Public Health, said that reaching parents who are more hesitant will be the biggest challenge ahead. Public health officials need to break down the science, possibly in question and answer form, for the lay people they need to enlist — and especially for parents who may worry about rare side effects, he said.

“I’m afraid parents will be much more attuned to reacting emotionally to what they hear from others,” Winsten said. “Government scientists should directly confront the vaccine side-effects issue by placing it in proper context.”

Surgeon General Vivek H. Murthy acknowledged as much at Wednesday’s briefing, describing plans to launch a public education campaign “that will meet parents where they are.”

“We will work with schools to send letters home to parents, who will convene doctors and health clinics, and support them in delivering vaccinations as soon as they have conversations with families,” Murthy said.

Above all else, he said, the effort would emphasize “reaching parents in their language and through the people they trust.”

Another issue may be the small number of doctors who have enrolled as vaccinators in some parts of the country.

“There are serious concerns that providers are just not signing up,” said Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials. Those worries are more widespread in southeastern states, which have been among the hardest hit in the delta surge, he said.

“Providers cite reasons such as the logistics of obtaining and administering the vaccine.” Some are also “concerned that this may be controversial, and they don’t want to have demonstrations in front of their clinics,” Plescia said.