Which COVID mitigation measures work

Research reveals some surprising findings about effective ways to reduce the spread in schools

By Brandon Ristoff
August 25, 2021

As schools reopen for the 2021-22 school year, questions remain about which COVID mitigation measures are actually effective. Certainly, everyone wants to protect students and teachers from COVID-19, but to ensure the strongest safety protocols – and not simply those that give the illusion of security – are in place, we must look to the evidence.

The most detailed study on this issue was featured in Nature Magazine. The researchers who wrote this article managed to isolate each of the mitigation measures to understand which reduce COVID-19 positivity and  which don’t. They found daily symptom screenings and cancellation of extracurricular programs to be the most powerful ways to reduce COVID-19. Other statistically significant mitigation measures found to reduce COVID-19 positivity include restricted entry and outdoor instruction (although the later one is probably the least practical measure to institute). 

Perhaps surprising given prevailing public policy in California, student masking, teacher masking, having the same teacher or students all day, reduced class size, closed cafeteria, extra desk space, not sharing supplies, and part-time, in-person instruction did not have a statistically significant impact on COVID-19 positivity.

Teacher masking and having the same students all day did have a statistically significant reduction in COVID-like illness. Unexpectedly, desk shields actually increased the likelihood that someone got COVID-19. This is most likely because it limits air flow and ventilation.

A few caveats need to be noted here. First, with the student and teacher masking mitigation methods, researchers considered the impact of mandates, not individual behavior. For example, a school could have a significant number of students and staff who choose to wear masks, even if the school does not have a mask mandate in place.

Second, the impact of these effects changes depending on the grade level of students. Students in high school are more likely than those in elementary school to get COVID-19. Finally, this research was done prior to vaccines or massive COVID-19 test screenings, so those mitigation measures should be considered in future research. 

Looking to our friends across the Atlantic, Europe has tended to downplay the need for student masking, at least for younger pupils. Some countries, including England and the Netherlands, are not requiring masks at any age, while others are limiting it to just secondary students. One of the arguments against young children wearing masks at school is that it has been shown that students are more irritable, less happy, and have difficulty concentrating while wearing them.

As schools work to reduce the spread of COVID-19, they must consider evidence-based measures that keep students and staff safe, while allowing learning to continue.

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