February 22, 2021
President Joe Biden has been pressing for more schools to return to in-person instruction, wanting all K-8 students back in the classroom five days a week by the end of April.
Research suggests transmission of viruses in schools is generally low, but a new analysis released Monday by the U.S. Centers for Disease Control and Prevention identifies teachers as the primary factor in the spread of COVID-19.
Researchers analyzed nine COVID-19 transmission clusters that occurred in December and January at a group of elementary schools in Marietta, a suburb of Atlanta, Georgia. In one case, 16 teachers, students and relatives were infected with the coronavirus.
A teacher was the first documented case in four of the clusters while only one of the nine clusters was clearly linked back to a student. In the other four clusters, investigators weren't able to identify where the transmission started.
"All nine transmission clusters involved less than ideal physical distancing, and five involved inadequate mask use by students," the researchers wrote. "Educators were central to in-school transmission networks."
Eight of the nine clusters involved teacher-to-student transmission at some point. In two clusters, transmission began after teachers infected one another during in-person meetings or lunch gatherings. They then went on to infect students.
Studies from the United Kingdom and Germany have revealed similar findings, according to the Associated Press. In the U.K. study, teacher-to-teacher transmission was the main source of spread in schools. In the German study, transmission rates tripled when the first documented case was a teacher.
Many U.S. school districts, including the School District of Philadelphia, still face challenges to getting students and teachers safely back in the classroom, including concerns over the proper ventilation of school buildings.
The CDC has emphasized the need for "multifaceted" strategies to prevent the spread of the coronavirus. Not enough space for proper social distance, improper mask use and too much close interaction in staff meetings, lunches and small group instruction with students have all been found to accelerate transmission in schools already back to in-person instruction.
Guidance issued earlier this month emphasized five essential strategies: face masks, social distancing, hand hygiene, sanitation and improving ventilation, and isolation and quarantines. Vaccines were considered an additional layer of prevention.