The researchers reviewed university health records to find nine groups of students who developed COVID around the same time, were in class together without social distancing, and had no known contact outside of school, suggesting they could have spread it in the classroom. classroom. However, genome analysis of the coronavirus samples from the clusters indicated that they were all likely infected elsewhere.
”When we looked at the genomes and compared them to each other, they were cousins but no closer than that.”, said the virologist at the Boston University School of Medicine. John Connor, a co-author. He said the study in JAMA Network Open provides an answer to a common question from last fall: “I just walked into a class with 80 people in it. How do I know I won’t get the disease from them?”
The university was able to conduct the study thanks to its comprehensive in-house testing program that includes DNA analysis of virus samples. The semester under study included 140,000 class sessions with an average size of 31 students, virtually all of whom were vaccinated as required. The classrooms were well ventilated, the researchers said.
Wearing masks in class was mandatory at the time the samples were taken, in contrast to next fall, when many colleges will have lifted the requirements. Another difference between then and now: the delta variant dominated last fall, while more contagious omicron variants like BA.5 reign supreme now.
Those differences surely matter, Connor said, but the study’s finding that classroom transmission between mask-wearing and vaccinated students was negligible may still inform future decisions about what to do during outbreaks.