Scientists have an obligation to strive for honesty. And on the question of whether kids should wear masks in schools—particularly preschools and elementary schools—here is what I conclude: The potential educational harms of mandatory-masking policies are much more firmly established, at least at this point, than their possible benefits in stopping the spread of COVID-19 in schools. To justify continued masking of schoolkids—with no end date in sight—we have to prove that masks benefit kids, and at what ages. States and communities that are considering masking policies just to be safe should recognize that being overly cautious has a cost, while the benefits are uncertain.
For most able-bodied adults, masks in public indoor settings pose only minor inconveniences. But children—who even amid the worrisome Delta-variant surge are experiencing serious outcomes from COVID-19 at far lower rates than people in older age groups are—have different needs and vulnerabilities than adults. Early childhood is a crucial period when humans develop cultural, language, and social skills, including the ability to detect emotion on other people’s faces. Social interactions with friends, parents, and caregivers are integral to fostering children’s growth and well-being.
Cloth masks do filter some aerosols, albeit not the majority, so they might catch some exhaled viral particles. Newly released results from a large trial in rural Bangladesh found that the widespread use of surgical masks by adults yields a significant reduction in the spread of symptomatic COVID-19. (The effect of cloth masks was more ambiguous, and the study did not include children.) But the issue facing educators and parents is whether a policy of mandatory masking makes school safer than a policy of optional masking—and whether the difference is enough to justify the imposition on kids.
No scientific consensus exists about the wisdom of mandatory-masking rules for schoolchildren. The World Health Organization, which recommends that children 12 and older wear masks under the same circumstances that adults do, specifically advises against masking kids age 5 and younger. Many European nations have been taking the agency’s advice. The United Kingdom has emphasized rapid testing instead of masking and has not required elementary-school students or their teachers to wear a face covering.
In the United States, though, current CDC and American Academy of Pediatrics guidelines call for kids age 2 and up to wear a mask in indoor school or day-care settings; the CDC specifically makes exceptions for napping and eating. (Masking very young children during sleep is inadvisable because of the risk of suffocation.) In other words, the prevailing wisdom in the U.S. calls for 2-to-4-year-olds to wear masks in day care for six or more hours while they are awake, but go unmasked while sleeping side by side in the same room. Shielding children from all coronavirus exposure is difficult for another practical reason: Little kids fidget with their masks.
A health recommendation that takes little account of how human beings act and what they need is unlikely to be successful. For instance, a diet that told you to eat just two carrots a day would theoretically result in dramatic weight loss. In practice, such a regimen could starve you of nutrients that your body requires. Moreover, overly strict diets often result in no weight loss at all, because nobody can stick to them. Similarly, mask mandates can be challenging for little children to follow and deprive them of stimuli they need.
In addition to recommending masks for young kids, CDC guidelines also urge masks for most vaccinated caregivers who work in infant day-care centers. This advice also deviates from standard practice in other nations, including the U.K. Many studies support the importance of babies seeing caregivers’ faces, and prior to the arrival of COVID-19, many American professional organizations, including the AAP, strongly agreed.
At least some fears about masking are exaggerated. Despite the claims of some critics, kids who wear a face covering are unlikely to suffer any meaningful problems exhaling carbon dioxide or inhaling oxygen. However, some mask wearers who exert themselves may subjectively feel short of breath. Unfortunately, some school districts are brushing aside that concern too. K–8 schools in affluent and highly educated Palo Alto, California, require kids to mask even outdoors at recess. San Diego schools recently announced an outdoor mask mandate as well. Yet scientists have known for some time that outdoor transmission is exceedingly rare, and many experts believe that outdoor masking is misguided. When masks are required in outdoor settings, kids may experience limitations in play, exercise tolerance, and socialization. And for what gain?
The benefits of mask requirements in schools might seem self-evident—they have to help contain the coronavirus, right?—but that may not be so. In Spain, masks are used in kids ages 6 and older. The authors of one study there examined the risk of viral spread at all ages. If masks provided a large benefit, then the transmission rate among 5-year-olds would be far higher than the rate among 6-year-olds.
The results don’t show that. Instead, they show that transmission rates, which were low among the youngest kids, steadily increased with age—rather than dropping sharply for older children subject to the face-covering requirement. This suggests that masking kids in school does not provide a major benefit and might provide none at all. And yet many officials prefer to double down on masking mandates, as if the fundamental policy were sound and only the people have failed.
Before limiting the amount of face-to-face human contact that children experience during many of their waking hours, policy makers should be acutely aware of what children could lose. Unfortunately, the downside of school mask requirements for children has been difficult to assess systematically because, until this pandemic, face-covering policies were never previously imposed on so many children for such a long period of time. Longitudinal studies cannot be performed on long-term outcomes, because there are no children in prior generations to study.
In the absence of systematic research on the costs and benefits of mask requirements for kids, the issue has been transformed into a right-left political battle. In addition to masking 2-year-olds, the CDC recommends the vaccination of people ages 12 and older. Because both recommendations come from a respected federal agency, supporters of both are likely to say they are “following the science.” But the evidence that supports vaccination is indisputable, in the form of multiple randomized studies, whereas the evidence to support school mask mandates for young kids is fragmentary at best. The problem with overselling unproven recommendations is that it risks turning people away from well-grounded ones.
Unfortunately, scientists have failed to conduct the kind of randomized trials that can provide more reliable answers. Here schools, counties, or districts would be assigned a mandatory or optional masking policy, and researchers could simply track their experience to determine which schools had more coronavirus spread. Kids wouldn’t be banned or prohibited from wearing masks, but rather the policy of making all kids wear masks would be rigorously tested.
In mid-March 2020, few could argue against erring on the side of caution. But nearly 18 months later, we owe it to children and their parents to answer the question properly: Do the benefits of masking kids in school outweigh the downsides? The honest answer in 2021 remains that we don’t know for sure.