BU study shows no COVID-19 spread in classrooms because of this factor

With more wide-open strategies set for the fall, will campuses be able to keep positive case counts low?
By: | August 10, 2022
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A new study from Boston University’s School of Medicine shows that in-person learning during the fall semester last year did not lead to any increase in the amount of COVID-19 positive cases on campus, but there’s a catch.

At BU, students not only were required to be vaccinated but they also were mandated to wear masks. The latter mitigation strategy—not social distancing—seemed to be highly effective at preventing transmissibility. Although there were nearly 900 cases that showed up in campus testing, none could be pinpointed to in-class experiences after genomic sequencing was completed.

“This study provides solid evidence that the disease mitigation events used by BU limited transmission in the classroom, something teachers and students everywhere would want to know,” said John Connor, associate professor of microbiology and one of the study’s authors. “Going back to full-occupancy, in-person teaching at Boston University did not lead to SARS-CoV-2 transmission in-class.”

Not yet anyway. After the spring semester ended, BU officials decided to lift mask requirements in classrooms while reducing the amount of surveillance testing. Those policies are in effect for the fall, so BU will provide an interesting test case to see whether a true face-to-face environment is safe from COVID spread. Many institutions, especially in the Deep South, haven’t had mask policies for more than a year, and while there have been sporadic outbreaks, there have been few hospitalizations and almost no deaths from COVID among college-age populations. BU’s populations are not only fully compliant with the two-dose schedule (98.7%) but are also mandated to have one booster shot, a key in protecting against serious outcomes from new strains of omicron.

Currently, cases across the United States have fallen 15% in the past two weeks and deaths remain low, though positivity rates continue to be high. Massachusetts is one of the states that has seen lower transmission throughout the summer. However, public health officials have warned that a lack of testing and trouble with home tests not picking up the current dominant BA.5 variant may be leading to underreporting of cases. One potential game-changer for those willing to embrace vaccines, including institutions of higher education, are companies like Pfizer working on doses that offer long-lasting protection from the newest coronavirus spinoffs, including BA.5. Those could be ready before the end of the year.


More from UB: Report: College COVID-19 mandates worked in reducing cases and deaths


While easing their requirements around masks, Boston University officials still encourage their use and mandate them on transportation and in health settings. After spending much of 2020 in remote settings, BU opened up campus last year for in-person learning in rooms that averaged 31 students but included those that hold 400. It conducted 140,000 classes, and from that researchers noted that nine cases were deemed to be potential instances for transmission (BU conducted nearly 600,000 PCR tests last fall, with 896 coming back positive). However, further genome testing among close contacts determined that none of them were in classes shared by individuals.

Researchers credited two mitigation strategies with BU’s success inside those spaces. The first was masking. The second was BU’s upgrade of its filtration systems that included MERV-13 filters and HEPA filtration in older buildings, as well as the allowance of faculty—during periods when the weather was warm enough—to open windows. Those initiatives also afforded faculty to conduct classes safely without masks, provided they were more than six feet from their students. While every institution is implementing different protocols this fall, researchers said one helpful way to assess spread is by doing the work they did.

“With the ongoing concern of safety for students, faculty, and staff as universities return to fully normal functioning, the use of epidemiology and genome sequencing is an effective model for understanding overall disease transmission safety in the classroom setting,” they said. “Understanding the risk of classroom transmission to assess against the benefits of in-person learning is important for university leadership decision-making.”