President Biden said Tuesday that he would use federal authority to offer coronavirus vaccinations to K-12 teachers and child care workers, with the aim of getting at least the first shot administered to all educators by the end of March.

The goal is to remove one of the major barriers to reopening schools — an urgent step for parents and children alike — but one that has been enormously controversial and complicated. Teachers, who have resisted going back in many communities, have said that they would be much more willing to return to school buildings if they are vaccinated first.

More than half the states have already put teachers into a high-priority category in their vaccination programs.

“Today, I’m using the full authority of the federal government; I’m directing every state to do the same,” Biden said. “My challenge to all states, territories and the District of Columbia is this: We want every educator, school staff member, child care worker to receive at least one shot by the end of the month of March.”

He said that starting next week, the federal government will use its pharmacy program to prioritize educators for vaccination and allow them to sign up for appointments.

“I want to be very clear,” he added. “Not every educator will be able to get their appointment in the first week. But our goal is to do everything we can to help every educator receive a shot this month.”

The status of K-12 education varies widely across the country, with some children able to attend in-person classes five days a week since the fall and others learning at home for nearly a year. Overall, the recent trend is toward more in-person options, with several large districts beginning to open buildings this week.

The White House also is seriously considering appointing a “czar” to coordinate the effort to reopen schools, an administration official said. And it’s possible that Linda Darling-Hammond, president of the California State Board of Education, who ran the education team for the Biden transition, will take on some sort of role in the reopening effort, people familiar with the process said.

Randi Weingarten, president of the American Federation of Teachers, welcomed the news about the vaccination effort.

“Vaccinations are a key ingredient to reopening schools safely, and this is the administration taking the steps to ramp up vaccinations for educators, which is great news for everyone who wants in-school learning,” she said.

During the presidential transition period, the Biden team considered a special program to prioritize teachers, but was dissuaded by the urgency of vaccinating older people, who are most likely to get very sick and require hospitalization, according to one person familiar with the conversations.

The Centers for Disease Control and Prevention has recommended that teachers be prioritized, suggesting they be part of the second group eligible for vaccination, behind only health-care workers and those in nursing homes and other senior settings.

But the CDC did not mandate it and, in its guidance for school districts, said teacher vaccination is not a prerequisite for schools to reopen. The White House struggled with its response to this. Several officials, including Vice President Harris, declined to back up the CDC, though ultimately the White House said it agreed.

Now the White House is bypassing state decision-making and giving teachers direct access to vaccine supply under its control through its pharmacy program.

The Biden administration began deploying vaccine doses directly to retail pharmacies on Feb. 11, starting with 1 million. That sum quickly doubled and has grown steadily since.

White House officials told governors Tuesday that the next wave of shipments to pharmacies would include 2.4 million doses. The initial locations, which included 6,500 stores, were selected in part to serve communities disproportionately affected by the virus, the administration said. The number of locations was expected to grow to as many as 40,000 pharmacies.

Until now, access to this program was governed by eligibility rules in each state, though the Biden administration said locations were chosen to prioritize hard-hit communities.

Notably, Biden’s announcement included child care workers, who have received far less attention than teachers have. Many of them have been working in person through much of the pandemic.

Isaac Stanley-Becker and Ashley Parker contributed to this report.