Do Children Really Transmit COVID-19 Less Than Adults? The Evidence Is Questionable


(USA Today)

Instructional assistants help students maintain social distancing as in-person learning resumes at Wilson Primary School in Phoenix, Arizona, August 17, 2020, photo by Cheney Orr/Reuters

Instructional assistants help students maintain social distancing as in-person learning resumes at Wilson Primary School in Phoenix, Arizona, August 17, 2020

Photo by Cheney Orr/Reuters

by Laura F. Garabedian and Rebecca Lee Haffajee

August 31, 2020

The theory that children are unlikely to contract or spread COVID-19—a notion that is guiding school reopening plans—may feel reassuring. It shouldn't. It's based on flawed science.

Even if school districts and policymakers are trying to make evidence-based decisions about classroom instruction, they may not understand the limitations of epidemiological studies. Until the research is more conclusive, schools need to operate under the assumption that everyone of all ages can become infected and spread the virus and take universal safety precautions.

It's hard to blame schools when messages from respected institutions are ambiguous. In its original guidance, the American Academy of Pediatrics urged schools to open for in-person learning, stating: “Although many questions remain, the preponderance of evidence indicates that … children may be less likely to become infected and to spread infection.” AAP is now saying additional research is needed to understand infectivity and transmissibility of COVID-19 in children, even as it “strongly advocates” for students to be physically present in schools.

Mixed Signals on School COVID-19 Safety

Similarly, the Massachusetts Department of Elementary and Secondary Education's fall reopening guidance (PDF) sent mixed signals. Its infection control recommendations include universal precautions in schools. At the same time, it cites studies reporting that very few COVID-19 clusters around the world originated in schools; adults are more likely to have the initial case in a household than a child; most recorded child-adult transmissions are from adult to child; infection rates are lower for children than for adults; and if exposed, children are less likely than adults to develop COVID-19.

Unfortunately, the above studies weren't designed to clearly determine children's COVID-19 risks. In part, that's because the research was conducted in spring and early summer, when schools were shut as part of widespread mitigation efforts. Kept home with few social activities, children were less likely to be exposed to the virus and bring it home than parents who might have to work or shop for food and other essentials.

Although the data may make it appear that children are less likely to get infected, the truth may be that they are less likely to be diagnosed.

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Children also are less likely than adults to exhibit symptoms, and thus are tested for COVID-19 less frequently. Although the data may make it appear that children are less likely to get infected, the truth may be that they are less likely to be diagnosed.

Newer evidence, albeit also imperfect, is already revising our understanding of COVID-19 in children. Recent studies have found that children with COVID-19 have a higher viral load than adults, and transmission rates are higher among school-age children than adults. A new report (PDF) from the American Academy of Pediatrics found a 40 percent increase in child cases (or almost 100,000 new infections) reported just during the last two weeks of July, when children were starting to return to normal activities in many parts of the country.

There is also evidence that the novel coronavirus was readily transmissible between children in schools and summer camps—including outbreaks in Georgia and Indiana—that did not adhere to public health recommendations on physical distancing, mask wearing, proper ventilation, and quarantining.

Promising Findings on Opening Schools

No one disputes that attending school in-person is critical for childhood development. So can U.S. classrooms reopen safely?

Other countries have managed it. Studies from Australia and Ireland demonstrate that a known COVID-19 case in a school can result in low or no transmission to other students and teachers if appropriate infection control strategies are in place. These promising findings suggest that stringent practices—universal masking, physical distancing, hygiene, proper ventilation, and frequent testing and contact tracing—can work, especially if there is low COVID-19 prevalence in the community.

That still does not mean children are not vectors for spread.

Right now, the evidence on children's rates of infection and transmission is inconclusive. Statements by political, education, and public health leaders that suggest otherwise may foster lax adherence to the precautions taken in schools and complacency among families outside of school.

Less than six months into this pandemic, we must remember that COVID-19 is still a new disease. Education leaders need to think critically about the current scientific evidence and understand the limitations of epidemiological studies. Until more is known, aggressive strategies to limit viral spread in schools are the best way to keep students and teachers safe.

Laura F. Garabedian is an assistant professor of population medicine at Harvard Medical School and Harvard Pilgrim Health Care Institute. Rebecca L. Haffajee is a policy researcher at the RAND Corporation and an adjunct assistant professor of health management and policy at the University of Michigan School of Public Health. Both have school-age children in Massachusetts.

This commentary originally appeared on USA Today on August 28, 2020. Commentary gives RAND researchers a platform to convey insights based on their professional expertise and often on their peer-reviewed research and analysis.