The study, performed between December and January at eight public elementary schools, identified "nine clusters of three or more epidemiologically linked COVID-19 cases... involving 13 educators and 32 students at six of the eight elementary schools."
It found that in four of those clusters, educators were the "index patient," or the source of the spread.
Nearly half the cases identified in the study, 15 of 31, resulted from two clusters which "involved probable educator-to-educator transmission during in-person meetings or lunches, which was followed by educator-to-student transmission in the classroom."
Eight of the nine clusters, the study said, involved "at least one educator and probable educator-to-student transmission." Three involved probable student-to-educator transmission.
"Educators were central to in-school transmission networks," the study said.
A student was identified as the index patient in one cluster, and in the other four "whether the index patient was the student, the educator, or both (i.e., two index cases occurred) could not be determined."
The study cited "less than ideal physical distancing" in all nine clusters, and "inadequate mask use by students" in five of them.
The findings could add fuel to the calls for teachers to be included in Georgia's vaccination eligibility. Gov. Brian Kemp had long resisted calls to include educators after he initially expanded the eligibility criteria to include adults 65 and over and employees of first responder agencies.
This week he said plans are being finalized to again expand eligibility.
The CDC report suggested vaccinating teachers could be an important tool in reopening schools and preventing the kinds of clusters observed in Marietta.
"Although not required for reopening schools, COVID-19 vaccination should be considered as an additional mitigation measure to be added when available," the report stated.