After public pressure, Florida allows pediatricians to order vaccines for very young children.

Facing withering pressure from medical professionals and the federal government, Florida began to allow pediatricians, children’s hospitals and other physicians on Friday to order coronavirus vaccines for the youngest children, according to state and White House officials. The shift will ensure that families will be able to get the shots at doctors’ offices, though later than in every other state in the country.

The White House praised the move as an important first step, calling it a “reversal” by Gov. Ron DeSantis, a Republican with presidential ambitions who frequently casts himself as a foil to President Biden. Mr. DeSantis’s administration insisted that it had not budged from its original position and only allowed orders once the Food and Drug Administration authorized the Moderna and Pfizer-BioNTech vaccines for very young children on Friday morning.

Unlike the other 49 states and the District of Columbia, Florida did not allow health care providers to preorder the vaccines ahead of the federal government’s June 14 deadline. As a result, no doses will be sent to doctors’ offices in the state during the first wave of vaccine shipments, scheduled to arrive starting on Monday. The second wave of preordered doses, which Florida also missed, is scheduled to arrive about a week later.

“The state of Florida intentionally missed multiple deadlines to order vaccines to protect its youngest kids,” Dr. Ashish K. Jha, the White House’s coronavirus response coordinator, told reporters on Friday.

In a statement, Bryan Griffin, a deputy press secretary for Mr. DeSantis, said characterizing Florida’s policy as a reversal was “patently false.”

“We have always maintained the position that the state of Florida has chosen not to be involved in the preordering or distribution of the vaccine for children under 5,” he said. “The state of Florida does not recommend the vaccine be administered to healthy children,” he added, referring to guidance the state issued in March against the advice of the Centers for Disease Control and Prevention.

State officials had said on Thursday that doctors could order vaccines as needed. But doing so requires using a state portal that was not opened for those orders until Friday.

Dr. Lisa Gwynn, the president of the Florida chapter of the American Academy of Pediatrics and an associate professor at the University of Miami, said she was in contact with the Florida Department of Health about the vaccines last week and was not informed that physicians would be allowed to place orders only after the shots received F.D.A. authorization.

“I’ve been back and forth, in touch with the people in the agency,” she said. “They’re not telling me this.”

Vaccinations for very young children are typically administered at pediatricians’ offices, but unlike pharmacies in the federal Covid vaccine program, doctors cannot order doses on their own, Dr. Gwynn said. She added that it seemed that some Florida officials were suggesting on Thursday that doctors order vaccines directly from the federal government, before the state opened its online portal.

“First they said providers could order directly from the federal government,” she noted. “That’s not true. We have to order through the state.”

On Thursday, Mr. DeSantis defended his administration’s refusal to preorder any vaccines for state-run medical facilities. That includes county-level public health offices, which are under state control.

“I would say we are affirmatively against the Covid vaccine for young kids,” he said. “These are the people who have zero risk of getting anything.”

By Friday morning, a congressional subcommittee overseeing the coronavirus response had sent Mr. DeSantis a letter urging him to reverse his position.

Noah Weiland contributed reporting.