DURHAM, N.C. — The question over requiring masks in schools has become a flashpoint for school board meetings around North Carolina and around the country. But new research shows face masks work to stop most transmission of the coronavirus in the classroom.

Researchers from Duke's ABC Science Collaborative studied almost 60,000 students from across 20 school districts in North Carolina that required everyone to wear masks inside school buildings. They found very few cases of COVID-19 transmission in the classroom, and no schools had to close, according to peer-reviewed research in the journal Pediatrics.

“The findings of this study are extremely encouraging for the health and safety of students and staff attending schools where universal masking is in place,” said Dr. Kanecia Zimmerman, co-chair of the ABC Science Collaborative.

What You Need To Know

  • Researchers at Duke tracked almost 60,000 students and 12,000 school staff members through two months of summer school

  • The 783 schools all required masks indoors regardless of vaccination status

  • The researchers, with the ABC Science Collaborative, found masks were very effective at keeping in-school COVID-19 transmission low and keeping schools open

  • Public health experts say more relief may be on the way for students as the latest spike in coronavirus cases wanes and the FDA considers vaccines for younger children

“The delta variant is more transmissible than previous ancestral variants, but transmission in schools can continue to be low with vaccination among those who are eligible, strict adherence to masking, and avoidance of pandemic fatigue,” she said.

The study does have some caveats. It was conducted during summer school, so there were fewer students in each school. It looked at cases from June 14 to Aug. 13. The latest spike began taking off in late July and early August with the highly contagious delta variant.

“Looking forward to the fall and winter, lunch and extracurricular activities will be areas that require additional attention to limit the transmission of COVID-19 within schools,” said Dr. Danny Benjamin, the other co-chair of the ABC Science Collaborative.

“As pediatricians and public health experts, we encourage schools to put mitigation strategies in place, such as vaccination, masking, and eating outside, to protect students and staff,” Benjamin said.  

The study looked at 59,561 K-12 students and 11,854 staff who were in-person at 783 different schools. In the study, the Duke researchers found 808 cases of the coronavirus acquired from the community and just 64 acquired in schools.

The schools follow the NC StrongSchools Toolkit, which means everyone was wearing masks inside school buildings, required 3 feet of social distancing in schools, and sent close contacts of COVID cases into quaranting. About 2,430 peple had to quarantine during the 2-month study.

"The delta variant has a reproductive number of about 7, meaning that, on average, in the community, one person infected with the delta variant infects 7 others. However, in schools that implemented universal masking, for every 13 people who acquired COVID-19 outside of school, one person acquired COVID-19 within schools," Duke University said in a statement.

"Though the study did not allow for a comparison to an unmasked setting because a statewide mask mandate was in place, data from other schools without a mask mandate during July-August 2021 showed these schools were 3.5 times more likely to have school-associated COVID-19 outbreaks than the schools in this study that required masking," the university said.

Most school districts in North Carolina continue to require masks in the classroom. But public health officials say there may be more hope on the horizon as the latest COVID spike wanes and the FDA considers authorizing vaccines for children as young as 5.