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For COVID-19 testing in schools to work, it has to be done right

Why is the Massachusetts Department of Elementary and Secondary Education committing considerable funding to districts for surveillance testing when its own policies undermine the effectiveness of this initiative?

Sebastian Sanchez, a student at Advanced Learning Academy, returns his COVID-19 test to a Community Labs staff member in San Antonio, Texas on Sept. 16.SCOTT STEPHEN BALL/NYT

As infectious diseases physicians with a child in the Boston Public Schools, we have been heartened by the enormous efforts BPS is taking to avert COVID-19 outbreaks in classrooms — including mandated vaccination or routine testing of staff and universal masking of students and staff. While these actions are laudable, we have found the COVID-19 testing policies of the Massachusetts Department of Elementary and Secondary Education to be puzzling and concerning. Testing has the potential to prevent COVID-19 outbreaks in schools, but to be effective it has to be done right.

Warning signs abound suggesting the transmission dynamics of COVID-19 in children have changed since the brief period when public schools were open last spring. By virtue of being ineligible for COVID-19 vaccination, children under 12 comprise one of the largest pools of unvaccinated individuals in the country. Although transmission in schools was lower than many had expected during the last academic year, the Delta variant, which became the dominant variant in the United States over the summer, is twice as transmissible as the wild type SARS COV2 strain. As a result, studies from last year suggesting relatively low COVID-19 transmission in schools may now be obsolete.


A recent CDC report reveals how rapidly the Delta variant can spread in classrooms. At a school in Marin County, which had one of the highest vaccination rates in California, a single unvaccinated teacher infected half of the 24 students in the classroom, despite excellent ventilation and a universal mask policy. Schools have been shut down within days of the start of the academic year across the country, including in Western Massachusetts, due to large numbers of infected students. Of more concern, COVID-19 cases in children have increased nearly 20-fold nationally since June and pediatric ICUs have reached or exceeded capacity in some southern states, which is the first time we have seen a crisis in pediatric care during this pandemic.

Testing provides benefits for preventing such outbreaks beyond what can be achieved by masking alone, especially in unvaccinated children. Evidence from colleges and universities suggests that regular surveillance testing is highly effective at preventing transmission if performed universally for all students at the right frequency. A modeling study published last year estimated that mandatory testing of all college students multiple times a week might effectively control outbreaks, even in dormitories, by identifying students with COVID-19 before they could infect others. Indeed, Tufts, Northeastern, and other universities employed mandatory surveillance testing strategies, with undergraduates tested multiple times a week, and managed to avoid major outbreaks. In contrast, Boston College started the 2020 academic year with a policy of testing less than one-quarter of its students only once a week and quickly experienced a major campus outbreak.


Learning from strategies that were used successfully in colleges and universities, some US cities are implementing rigorous surveillance testing policies this year for students in public schools. President Biden has emphasized the importance of surveillance testing in schools. In particular, Los Angeles is leading the way not only by making vaccination mandatory for age-eligible students but also by making weekly testing mandatory for all public school students.

In contrast, the Massachusetts DESE, which is providing funding to school districts for surveillance testing, has disallowed districts from instituting mandatory testing policies. Moreover, districts cannot institute an “opt-out” consent policy, in which children are automatically enrolled in testing unless their parents choose to disenroll them. As a result, districts can only offer parents the option to “opt-in” their children for weekly pooled surveillance testing. Research in the behavioral economics literature shows that opt-in policies lead to much lower rates of program enrollment than opt-out policies. Not surprisingly, the surveillance testing enrollment rates in BPS last spring were low (only 22 percent) and, as of two weeks ago, less than one-third of children were enrolled in surveillance testing for this school year. With such low rates of enrollment, we have to wonder: Why is the Massachusetts DESE committing considerable funding to districts for surveillance testing when its own policies undermine the effectiveness of this initiative?


Other testing policies are being implemented that may be less effective than expected in the era of the Delta variant. For example, if a student in BPS is found to be COVID-19 positive (by in-school testing or otherwise), the current policy is to work with the Boston Public Health Commission to identify close contacts of the student. For other asymptomatic students in the same classroom, only those deemed to be close contacts would be advised to get tested. It would be wiser to recommend testing of all students in a classroom when a student or teacher tests positive given the Delta variant’s high transmissibility and the challenges of contact tracing in classrooms with young children who interact throughout the day. Consistent with the “test and stay” approach BPS is adopting, asymptomatic children would not need to quarantine while waiting for their test results, but such broad application testing would quickly identify most infected children and limit ongoing transmission.


We recognize that there are many uncertainties regarding COVID-19 as we enter this school year. On the one hand, Massachusetts has a higher adult vaccination rate than many other states. On the other hand, children under 12 remain unvaccinated and we are facing a more transmissible variant. If we have learned anything throughout the year and a half of this pandemic, it is that it is easy to underestimate COVID. We need to remain cautious in the short term as we learn more about how the Delta variant behaves in school settings and until children under 12 become eligible for vaccination. If our goal is to keep children in classrooms, then we need to aim for excellence and implement all of our tools effectively. Testing is a key part of the toolbox. Massachusetts and BPS should be proactive in preparing for the worst-case scenarios, so that children — and our school systems — are set up to succeed.

Lakshmi Ganapathi is an infectious diseases physician and an instructor of pediatrics at Harvard Medical School. Ramnath Subbaraman is an infectious diseases physician and an assistant professor at the Tufts University School of Medicine.