On September 24, the Center for Disease Control and Prevention (CDC) released new studies indicating that school mask requirements are essential in stopping the spread of COVID-19. Increases in pediatric cases of COVID-19 were observed in counties that do not require people to wear a mask.

Teenagers account for the majority of cases nationwide, according to the CDC. In Arizona’s two most populated counties, Maricopa and Pima, it was found that schools were 3.5 more likely to have COVID-19 outbreaks if they didn’t have a mask requirement, as compared to schools that have required everyone to wear a face mask since the first day of school.

Read what one Texas teen had to say about the return to in-person learning.

The release of these studies by the CDC come as several states, such as Florida, Texas and Arizona, have tried to ban school districts from enforcing mask requirements. The Department of Education has put schools in Iowa, South Carolina and Tennessee under investigation for banning masks. “The department will fight to protect every student’s right to access in-person learning safely and the rights of local educators to put in place policies that allow all students to return to the classroom full-time in-person safely this fall,” said Secretary of Education Miguel Cardona.

Last week, the National School Boards Association and the Superintendents Association issued a joint statement in response to threats and violence towards school personnel related to safe school openings. “School leaders across the country are facing threats because they are simply trying to follow the health and scientific safety guidance issued by federal, state, and local health policy experts,” it states.

The CDC recommends wearing a mask in school for all students, staff, teachers and visitors, regardless of vaccination status. “Promoting vaccination of eligible persons, mask wearing, and screening testing are all proven methods to continue to work towards the end of the COVID-19 pandemic.”