WASHINGTON (NewsNation Now) — The Director of the Centers for Disease Control and Prevention said Wednesday that vaccinating teachers is not a requirement to return to in-person instruction.

“Vaccination of teachers is not a prerequisite for safe reopening of schools,” said Dr. Rochelle Walensky during a White House COVID-19 Response briefing.

Walensky cited CDC data showing that social distancing and wearing a mask significantly reduce the spread of the virus in school settings. President Joe Biden has pledged to ensure nearly all K-8 schools will reopen for in-person instruction in the first 100 days of his administration.

Teachers are prioritized as “essential workers” under the CDC’s vaccination plans, though many have yet to receive doses as the nation continues to face a supply shortage of the vaccine.

The nation’s top disease expert Dr. Anthony Fauci said it was premature to consider requiring a coronavirus vaccine for access to places such as federal property or schools when only a fraction of the country has received a shot.

“It’s no time to talk about that now while we still have a great demand that outstrips the supply,” Fauci said.

In some cities like Chicago, teachers’ unions and the city are still negotiating the terms of coming back to the classroom. Some teachers’ unions balk at resuming in-person instruction before teachers are inoculated.

“We want our frontline health care workers to be vaccinated first. That is the priority. Teachers are not trying to cut the line but what we are saying is make us a priority, which is not something CPS [Chicago Public Schools] has done as part of their plan to bring us back into schools,” said Quentin Washington, a member of the Chicago Teachers Union. “That would make teachers feel a lot safer, it would make communities feel a lot safer.”

More than 52 million vaccine doses have been distributed across the United States, with more than 32 million doses administered as of Wednesday morning, according to the CDC.

The government said Tuesday that starting next week, roughly 6,500 pharmacies around the country will receive a total of 1 million doses of vaccine to accelerate vaccinations around the country. The number of participating pharmacies, and the allocation of vaccines, are expected to expand as drugmakers increase production.

That is in addition to 10.5 million doses that the federal government plans to ship weekly to states and territories for the next three weeks.

On Wednesday, Biden’s COVID-19 czar Jeffrey Zients announced the opening of two coronavirus vaccination sites in East Oakland and East Los Angeles, two of the hardest-hit communities in the already ravaged California.

The sites will launch at the Oakland Coliseum and at California State University, Los Angeles. Zients called those sites “just the beginning” of the Biden administration’s push to speed the pace of vaccinations, particularly in area suffering the brunt of illnesses and death.

Fauci and Walensky also addressed the importance of public health measures including mask wearing and social distancing to prevent the spread of new and potentially more contagious virus variants.

“If you have an open playing field for the virus, they will replicate and they will mutate,” said Fauci. “The best way to prevent that is the implementation of the public health measures.”

At a briefing last week, Fauci said the emergence and increasing spread of coronavirus mutations means that vaccine makers must be ready to make new shots to stay ahead of the public health crisis.

“You can be almost certain that as long as there is a lot of virus circulating in the community, there will be the evolution of mutants, because that is what viruses do,” the government’s top infectious disease expert said Friday.

“This is a wake-up call to all of us,” he said, noting government scientists will be working to keep pace with virus mutations.