About The Study: The results of this study of 140,000 class meetings suggest that in-class transmission of SAR-CoV-2 in an urban university with masking and vaccine protocols in-place was negligible.
Question Is there evidence of in-class transmission of SARS-CoV-2 on a university campus that had mandated vaccination and masking?
Findings In this cohort study of 140 000 class meetings at a large US university, there were over 850 cases of SARS-CoV-2 infection identified through weekly surveillance testing of all students and faculty on campus during the fall 2021 semester. There were 9 instances of potential in-class transmission identified as identical lineages confirmed by SARS-CoV-2 genome sequencing, and none of these instances were confirmed to be in-class transmission.
Meaning These results suggest that in-class transmission of SAR-CoV-2 in an urban university with masking and vaccine protocols in-place was negligible.
Importance SARS-CoV-2, the causative agent of COVID-19, has displayed person-to-person transmission in a variety of indoor situations. This potential for robust transmission has posed significant challenges and concerns for day-to-day activities of colleges and universities where indoor learning is a focus for students, faculty, and staff.
Objective To assess whether in-class instruction without any physical distancing, but with other public health mitigation strategies, is a risk for driving SARS-CoV-2 transmission.
Design, Setting, and Participants This cohort study examined the evidence for SARS-CoV-2 transmission on a large urban US university campus using contact tracing, class attendance, and whole genome sequencing during the 2021 fall semester. Eligible participants were on-campus and off-campus individuals involved in campus activities. Data were analyzed between September and December 2021.
Exposures Participation in class and work activities on a campus with mandated vaccination and indoor masking but that was otherwise fully open without physical distancing during a time of ongoing transmission of SARS-CoV-2, both at the university and in the surrounding counties.
Main Outcomes and Measures Likelihood of in-class infection was assessed by measuring the genetic distance between all potential in-class transmission pairings using polymerase chain reaction testing.
Results More than 600 000 polymerase chain reaction tests were conducted throughout the semester, with 896 tests (0.1%) showing detectable SARS-CoV-2; there were over 850 cases of SARS-CoV-2 infection identified through weekly surveillance testing of all students and faculty on campus during the fall 2021 semester. The rolling mean average of positive tests ranged between 4 and 27 daily cases. Of more than 140 000 in-person class events and a total student population of 33 000 between graduate and undergraduate students, only 9 instances of potential in-class transmission were identified, accounting for 0.0045% of all classroom meetings.
Conclusions and Relevance In this cohort study, the data suggested that under robust transmission abatement strategies, in-class instruction was not an appreciable source of disease transmission.