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Study: Teachers Play Role in School COVID Spread

photo of surgical mask

Feb. 22, 2021 -- A new contact tracing study of COVID-19 infections in eight Atlanta-area elementary schools finds that teachers bring the infection to school at least as often as they catch it from their students.

The study, by the CDC and the Georgia Department of Public Health, traced positive cases linked to any of eight elementary schools in the Marietta City Schools, where in-person instruction resumed in November.

The schools followed some of the CDC’s recommended safety protocols, like requiring masks and limiting visitors, but others were harder to pull off. School desks had clear plastic dividers, but were less than 3 feet apart because the school didn’t have enough space to spread students out. And teachers sometimes worked with students close-up, in small groups.

The investigation took place over roughly 7 weeks between December 2020 and the end of January 2021. Because it spanned the winter holidays, there were only 24 days of in-person school.

Community transmission was high, with the surrounding county seeing a 300% jump in its cases over this period. So the study provides a real-world look at how COVID-19 can move through schools when the infection rates are high outside the school walls.

Out of 2,600 students and 700 staff, researchers identified nine clusters of infections involving 45 positive cases: 13 teachers and 32 students. In four out of the nine clusters, teachers were the index case, meaning they were the first to catch the virus and bring it to their classrooms. In one cluster, a student was the first case. And in four others, teachers and students got sick at roughly the same time, so investigators couldn’t be sure who was first to get it.

All contacts of identified cases were offered free testing, but only 60% took researchers up on that offer, so cases are likely to be underestimated. Still, infections appeared to be reassuringly low, and they didn’t always come home. Among 69 people who lived in the same houses as the school-related cases, 18 (26%) tested positive.

Researchers say the school study findings offer a few lessons. First, teachers seem to play a key role in the spread of the infection.

In one case, one teacher passed it to another during in-person meetings. The second teacher then gave it to students. Studies from schools in Germany and the U.K. also found that teachers were the most frequent drivers of spread. They say this means that teachers and other school staff need to be taking COVID-19 precautions even when they’re outside school. They also say adult interactions at school should also be lessened. And teachers, along with other essential workers, should be offered vaccinations as soon as enough doses are available since this, too, should help stop the spread.

“The findings highlight the importance of scaling up vaccination efforts across the country as well as the continued need to prioritize teachers and other school staff,” said CDC Director Rochelle Walensky, MD, at a briefing of the White House COVID-19 Response Team.

The study also underscores that consistency counts. Kids and adults wore masks during the study, but didn’t always do it correctly, something that may have contributed to the spread of cases in some of the clusters.

Lindsay Kalter contributed to this report. 

WebMD Health News Brief


Morbidity and Mortality Weekly Report, Feb. 22, 2021.

News briefing, White House COVID response team, Feb. 22, 2021.

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