CDC study: Teachers key to COVID-19 infections in 1 district

FILE - In this Dec. 8, 2020 file photo, Rochelle Walensky, speaks during an event at The Queen theater in Wilmington, Del. The U.S. is scrambling to expand DNA mapping of coronavirus samples to identify potentially deadlier mutations starting to spread around the country.(AP Photo/Susan Walsh)
FILE - In this Dec. 8, 2020 file photo, Rochelle Walensky, speaks during an event at The Queen theater in Wilmington, Del. The U.S. is scrambling to expand DNA mapping of coronavirus samples to identify potentially deadlier mutations starting to spread around the country.(AP Photo/Susan Walsh) (Copyright 2020 The Associated Press. All rights reserved.)

ATLANTA – A new study finds that teachers may be more important drivers of COVID-19 transmission in schools than students.

The paper released Monday by the U.S. Centers for Disease Control and Prevention studies nine COVID-19 transmission clusters in elementary schools in the Atlanta suburb of Marietta in December and January, That included one cluster where 16 teachers, students and relatives of students at home were infected.

In only one of the nine clusters was a student clearly the first documented case, while a teacher was the first documented case in four clusters. In another four, the first case was unclear. Of the nine clusters, eight involved probable teacher-to-student transmission. Two clusters saw teachers infect each other during in-person meetings or lunches, with a teacher then infecting other students.

“Educators played an important role in the spread," CDC Director Dr. Rochelle Walensky told reporters in an online briefing Monday. "COVID-19 spread often occurred during in-person meetings or lunches and then subsequently spread to classrooms.

The findings line up with studies from the United Kingdom that found teacher-to-teacher was the most common type of school transmission there, and a German study that found in-school transmission rates were three times higher when the first documented case was a teacher. In some American districts, schools have had to go all-virtual because so many teachers have been exposed to the virus.

Other research has suggested that there's low transmission of viruses in schools and that they should reopen for in-person instruction, a message that President Joe Biden's administration has been pushing in recent weeks to mixed success. The 8,700-student Marietta district, like all but a handful in Georgia, has been offering in-person classes since the fall. Superintendent Grant Rivera said more than 90% of elementary students came back in person, making some classrooms relatively crowded.

All the Marietta clusters also involved “less than ideal physical distancing,” with students often less than 3 feet apart, although plastic dividers were placed on desks.

“The two main reasons for the spread of COVID-19 in these schools were inadequate physical distancing and mask adherence,” Walensky said.