Mandatory masking led to drop in COVID-19 infection rate among schoolchildren

A masking mandate in North Carolina schools during the first weeks of the Delta Variant wave resulted in a lower infection rate among schoolchildren and staff members than has been reported in the community at Sense large, according to a new report from the ABC Science Collaborative.

Published in the journal Pediatrics, the analysis includes data from 20 North Carolina school districts that ran a summer school or year-round school between June 14, 2021 and August 13, 2021. The Delta variant is became the dominant strain of SARS-CoV -2 circulating in the United States in early July 2021.

Data was submitted by 783 K-12 schools, representing 59,561 students and 11,854 staff who attended in person. School districts in the analysis followed the North Carolina Department of Health and Human Services (NCDHHS) StrongSchoolsNC toolkit, which recommended, but did not require, at least three feet of physical distance between people. . The status mask mandate for K-12 parameters was in effect during the study period.

The ABC Science Collaborative analyzed COVID-19 data provided by the districts. Two measures were used to estimate the spread of the Delta variant within schools: a report showing cases acquired in the community versus those acquired in school and the estimated secondary attack, or rate of acquired infection. at school.

During the study, 808 cases acquired in the community were reported against 64 cases acquired in school. The Delta variant has a reproductive number of around 7, which means that on average, in the community, one person infected with the Delta variant infects another 7. However, in schools that have implemented universal masking, for 13 people who contracted COVID-19 outside of school, one person contracted COVID-19 in schools.

As a result of exposure to COVID-19 at school, 2,431 close contacts were quarantined and 64 people contracted infections in schools, resulting in a secondary attack rate of 2.6 %. This secondary attack rate is slightly higher than the secondary attack rate of about 1% that the ABC Science Collaborative found before the emergence of the Delta variant. This is probably due to the more infectious nature of the Delta variant.

The results of this study are extremely encouraging for the health and safety of students and staff attending schools where universal masking is in place. The Delta variant is more transmissible than previous ancestral variants, but transmission in schools may continue to be low with vaccination among those who are eligible, strict adherence to masking, and avoidance of pandemic fatigue. “

Kanecia Zimmerman, MD, MPH, Co-Chair, ABC Science Collaborative

Although the study did not allow a comparison to an unmasked setting because a statewide mask warrant was in place, data from other schools without a mask warrant in July-August 2021 did showed that these schools were 3.5 times more likely to have COVID- associated with school. 19 epidemics than the schools in this study that required masking.

The data from this study also underscores the importance of staying alert during times of the school day when strict mask compliance may not be possible.

“Looking forward to fall and winter, lunch and extracurricular activities will be areas that will require additional attention to limit the transmission of COVID-19 in schools,” said Danny Benjamin, MD, PhD , MPH, co-chair of the ABC Science Collaborative. . “As pediatricians and public health experts, we encourage schools to put in place mitigation strategies, such as immunizations, masking and eating out, to protect students and staff.”