In one article, authors compared school-associated COVID cases in TK-12 schools in Los Angeles County with cases for all children ages 5-17. During the period of Sept. 1, 2020–March 31, 2021, they found school-associated case rates for students to be much lower than in the broader community.

“In schools with safety protocols in place for prevention and containment, case rates in children and adolescents were 3.4 times lower during the winter peak compared with rates in the community,” according to the article, which notes that the analysis reflects pre-Delta variant transmissions. “A multipronged prevention strategy, including masking, physical distancing, testing, and most recently vaccination of children and adolescents aged ≥12 years, will remain critical to reducing transmission as more students return to the classroom.”

Another article investigated the causes of a May COVID outbreak at a Marin County elementary school.

The outbreak originated with an unvaccinated teacher who came to work while experiencing COVID-like symptoms, which she attributed to allergies. Although the school required masks to be worn indoors, the teacher was reportedly known to read to the children out loud without a mask.

In a class of 24 students, 12 of 22 who were tested were positive for the Delta variant of COVID, with the students sitting closest to the teacher more likely to be infected, according to the CDC. The school had all desks separated by 6 feet and also had portable high-efficiency particulate air filters and doors and windows were left open.

“This outbreak of COVID-19 that originated with an unvaccinated teacher highlights the importance of vaccinating school staff members who are in close indoor contact with children ineligible for vaccination as schools reopen,” the authors write. “The outbreak’s attack rate highlights the Delta variant’s increased transmissibility and potential for rapid spread, especially in unvaccinated populations such as schoolchildren too young for vaccination.”