The Centers for Disease Control and Prevention on Friday issued guidance saying that vaccinations are not required for in-person learning.
The CDC is not demanding schools reopen, but its guidance states that "screening testing and vaccinations are not prerequisites for safe reopening if students and staff consistently implement the mitigation strategies" the agency recommends.
Those measures include analyzing health data, making masks mandatory and ensuring six-foot social distancing.
Teachers are among the second priority group for the COVID-19 vaccine in line with CDC guidelines, along with other essential workers, after frontline health care workers and long-term care facility residents.
The CDC and Duke Health each released studies in January showing that in-person learning is generally safe if schools take proper safety precautions, but some teachers unions argue that schools will not be prepared to reopen fully until all school staff members are vaccinated.
Others have pushed back even further, saying it still won't be safe to reopen after that. Unions say schools need more funding for better ventilation systems before students and staff can safely return.
The new CDC guidance, however, has spurred more confidence among educators that schools can reopen without putting students and staff at significant risk of catching the virus.
"Schools should be the safest place in any community," National Education Association President Becky Pringle said in a Friday statement. "Now that we have clear CDC guidance, state and local decision-makers need to be able to look educators, students and parents in the eyes and ensure that they are safe with full confidence."
American Federation of Teachers President Randi Weingarten similarly said that the CDC's guidance represents "a rigorous road map, based on science, that [ATF] members can use to fight for a safe reopening," adding that the Trump administration "meddled with the facts and stoked mass chaos and confusion."
Some public school students in towns and cities across the country have been learning remotely for a year. Being isolated at home, away from friends and school activities, has had a negative effect on some students' learning abilities and general mental well-being, experts say.
Parents across the U.S. have held protests and rallies in an effort to make their voices heard and get local governments to allow their children to return to in-person classes.
President Biden on Friday welcomed the CDC's guidance and doubled down on his goal to reopen most public schools by the end of his first 100 days in office.
"These scientific guidelines tell us that our schools are safer when we have appropriate distancing in classrooms and on school buses, when masks are worn consistently and properly, when handwashing occurs regularly, and when we are able to effectively respond to cases through testing and contact tracing, and when we follow other recommended steps," Biden said in a statement.
He added that "some schools will need more teachers and support staff to ensure smaller class sizes, more buses and bus drivers to transport our kids safely, more spaces to conduct in-person instruction, and more protective equipment, school cleaning services, and physical alterations to reduce the risk of spread of the virus."
House Speaker Nancy Pelosi took the CDC's new guidance as an opportunity to push for more school funding in the next COVID-19 relief bill.
"Our House Committees are working expeditiously to draft and pass by the end of the month President Biden’s American Rescue Plan legislation, which makes a strong and necessary $130 billion investment for safe school re-opening and for our K-12 students," she said in a statement.
The funding would go toward repairing ventilation systems, reducing class sizes, implementing social distancing measures, purchasing personal protective equipment and hiring support staff. The legislation would also allocate $7 billion "to close the digital divide," which is "especially important for students and teachers in communities at high risk," she said.