The American Academy of Pediatrics issued new Covid-19 guidelines for schools on Monday recommending that everyone over the age of 2 wear masks in the fall, even if they have been vaccinated. Exceptions can be made for those with medical or developmental conditions that make it difficult to wear masks, the group said.

The universal masking recommendation is a departure from the guidelines issued earlier this month by the Centers for Disease Control and Prevention that only recommend masking in schools for unvaccinated people over the age of 2. These guidelines strongly imply that fully vaccinated children and adults are not required to wear masks in the classroom – although they also said individual schools are free to implement universal masking requirements.

However, in many ways the two directives are similar. The AAP, like the CDC, stressed the importance of returning to personal learning.

“Our priority must be getting children back to school with their friends and teachers – and we are all helping to ensure that it happens safely,” said Dr. Sonja O’Leary, the chair of the AAP Council on School Health, in a statement.

Like the CDC, the AAP recommended a “layered” approach that combines a variety of measures to reduce the risk of coronavirus transmission. In addition to universal masking, these measures include vaccinations, improved ventilation, virus testing, quarantines, and cleaning and disinfection, the group said.

The AAP gave several reasons for its universal masking recommendation.

Many students are too young to be eligible for the vaccines, which are only approved for those aged 12 and over, the group found. And universal masking could reduce overall transmission of the virus and help protect those who are not vaccinated.

The group also cited concerns about more communicable virus variants and the possibility that vaccination rates could be low in the surrounding community, which could increase the risk of an outbreak at a particular school. The AAP also recommended universal masking because it can be difficult to verify that individual students or employees have been vaccinated.

Some state and local officials have already announced that they will not be calling for universal masking this fall, and at least eight states have banned such mandates.

The AAP guideline didn’t stop recommending vaccine mandates, but it said they might ultimately be needed. “It may be necessary for schools to collect Covid-19 vaccine information from staff and students and for schools to require Covid-19 vaccination for personal learning,” the guidelines say.