Reviewed by Emily Thorell, MD, MSCI University of Utah Health and Zachary Willis, MD, MPH University of North Carolina School of Medicine
At the outset of the COVID-19 pandemic, schools preemptively closed across the United States. At that time, this measure appeared to be reasonable: schools and other childcare settings have long been key venues of transmission for viral respiratory pathogens such as influenza. As the pandemic progressed, however, it became increasingly clear that susceptibility to severe COVID-19 disease increases with age and that children may not spread SARS-CoV-2 as efficiently as adults. Despite the growing evidence that safe reopening was possible, many schools remained closed deep into the 2020-2021 school year.
Zimmerman, et al., reported on the experience of school districts in North Carolina over 9 weeks in the fall of 2020. The schools participated in the ABC Science Collaborative (ABCs), which included mitigation recommendations, stakeholder engagement, and educational sessions for participating districts. Eleven participating districts offered in-person instruction for the entire 9-week period studied. Out of approximately 90,000 students and staff attending or working in those school districts, there were 773 cases of community-acquired COVID-19. Following investigations by local health departments, a total of 32 cases of secondary transmission were discovered, or 0.04 secondary cases per community-acquired case. The authors conclude that, with appropriate mitigation, in-school transmission is rare.
One important barrier to full return to in-person instruction was the original CDC recommendation that students maintain a minimum of 6 feet of distance from each other. In another study, van den Berg, et al., analyzed the incidence of COVID-19 in students and staff in Massachusetts schools, comparing schools mandating at least 3 feet versus at least 6 feet of distance between students. There was no difference in the incidence rate of COVID-19 for either students or staff between the two policies in unadjusted or adjusted models. It is important to note that physical distance was only one component of the mitigation strategy and that schools were compared on the basis of their policy requirement, not the actual distance between individuals. The authors conclude that 3 feet of distance between individuals in school settings is as safe as 6 feet.
Finally, a recent study described the experience of 54 YMCA day camps with over 5000 youth, also in North Carolina, over a 147-day period March to August 2020. Mitigation strategies for the indoor/outdoor day camps were similar to schools and included masks for both indoor and outdoor activities, symptom screening, temperature checks, hand hygiene, physical distancing and small cohorts. Per an internal audit in June, mask compliance was >95% among campers and staff. There were 17 primary COVID-19 cases in 9 youth and 8 staff during the study period and only 2 secondary infections. The authors conclude that the benefits of in-person programming in recreation settings may outweigh the risks of viral transmission.
These data are reassuring that using appropriate mitigation strategies, including facial coverings, substantially decreases risk of viral transmission in both schools and day camp settings. Anyone who has had children at home in the last year knows that both children and parents benefit from kids being able to attend in-person education/recreation for many reasons. Importantly, the evidence base to inform how to accomplish these goals safely are increasing.
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