Students wearing masks listen to teacher Dorene Scala during summer third grade school at Hooper Avenue School on June 23, 2021 in Los Angeles.

Carolyn Cole | Los Angeles Times | Getty Images

The Centers for Disease Control and Prevention updated their public health guidelines for schools on Friday, saying that fully vaccinated teachers and students are not required to wear masks in school buildings.

The CDC’s new guidance comes about two months after federal health officials approved the use of the Pfizer BioNTech Covid vaccine for children ages 12-15, so middle and high school students could get the syringes before the fall semester can.

Teachers and students who are not vaccinated should continue to wear masks indoors, the U.S. agency said, adding that the practice is especially important when kept indoors and in crowded environments when social distancing cannot be observed .

The agency also said it still recommends that students stay at least 3 feet apart in classrooms, combined with the wearing of indoor masks by those who are not fully vaccinated to reduce the risk of transmitting the virus.

“When it is not possible to maintain a physical distance of at least 3 feet, e.g. B. If schools cannot be fully reopened while observing these intervals, it is particularly important to use several other prevention strategies, such as wrote in his instructions.

The CDC guidelines are just a recommendation, leaving it up to the states and local school districts to override their masking rules for specific people. It is unlikely to affect students under the age of 12 who are currently not eligible for a Covid vaccine in the United States

Covid prevention strategies remain critical to protecting people from the virus, especially in areas with medium to high transmission rates in the community, the agency said.

The updated guidelines come as several states in the US have largely phased out their mask requirements, social distancing and other pandemic-related restrictions as Covid vaccines helped reduce the number of new infections and deaths.

In mid-May, the CDC announced that fully vaccinated people would not need to wear masks in most environments, whether indoors or outdoors. They are still expected to wear masks on public transport, the agency said, such as on planes, buses and trains. The mask mandate of the federal government in public transport is to expire on September 13, unless the CDC renews it.

The guidelines can be controversial as scientists and other health experts say internal mask regulations could return this fall, especially in low-vaccination states as the highly transmissible Delta variant spreads in the US

Delta is already the predominant variant in the US and will hit the states with the lowest vaccination rates the hardest – unless those states and companies reintroduce mask rules, capacity limits, and other public health measures, which they largely withdrew in recent months have, say experts.

“I could foresee that in certain parts of the country mask requirements, distance and occupancy restrictions for indoor areas would be reintroduced in the coming months,” said Lawrence Gostin, director of the World Health Organization’s Cooperation Center for National and Global Health Law.

Some places, such as Los Angeles County, California, recommend that “everyone, regardless of vaccination status,” wear masks as a safety measure indoors in public places.

In Mississippi, where less than a third of the state’s eligible population is fully vaccinated, officials last week recommended that all residents continue to wear masks indoors as Delta becomes the predominant variety in the state.

Detroit public schools require everyone to wear a mask unless everyone in the classroom has been vaccinated. Philadelphia requires all students and public school staff to wear masks indoors, even if they have been vaccinated. Masks are not required in Houston schools.

–The Associated Press contributed to this report.