Asymptomatic and contagious. Young children with Covid appear especially likely to silently spread the virus, new study suggests.
New data suggests that many likely are. Routine screening remains a strong strategy for keeping young kids in daycare and preschool.
The goal is to keep daycare and preschools open in the face of Covid-19. The debate centers on how to achieve that.
Strategy #1: Bury our heads in the sand and hope for the best.
Strategy #2: Implement measures that decrease Covid-19 spread.
New data published in JAMA Network Open suggests that Strategy #1 is doomed to fail and that asymptomatic testing is likely to maximize in-person care/school days by keeping our youngest children from spreading Covid-19 in “congregate” settings. That’s because in young children, researchers found no correlation between the presence of symptoms and coronavirus viral loads (higher viral loads are a good proxy for contagiousness; a correlation between symptoms and viral load was found in adults, interestingly.)
This indicates that relying on symptom screening alone would likely fail to detect outbreaks in preschools and daycares in time to stifle them. In fact, young children with asymptomatic SARS-CoV-2 infection were found in the study to have similar viral loads as infected children with one or more reported symptoms. This means that asymptomatic cases were indeed likely causing spread in daycare and school settings during 2020-2021 (when the study was conducted), and it’s reasonable to hypothesize that things only got worse during the Omicron wave this year.
The data also imply that many infections among very young children are likely never detected, because of how mild they are. That’s good news by itself. That said, it’s possible that the higher rates of asymptomatic infection seen in children under age 5 owes to kids being less likely to be able to report some types of symptoms. Indeed, for children under 2, only a subset of symptoms were solicited by researchers. For example, parents and their children under age two were not asked about chest pain, while older children and adults were. If a 1-year-old experienced something like chest pain, we could never really know that because there is no reasonable way for the child to indicate such a thing. But that does not mean chest pain wasn’t present, even in some nondescript, nebulous way. All of this underscores the larger point. If a baby with coronavirus experienced symptoms that only an older child with an infection would have been able to report (or that a parent could observe), we’d simply never know that. So, from our perspective, those kids would be categorized as asymptomatic, even though if we could somehow get inside their tiny little minds, we’d know they actually did have some of these imperceptible symptoms. Testing can therefore bridge the gap between what a young child or their parent can report and the ability to detect contagious infections. In turn, catching an outbreak before it spreads to an entire group of children in a daycare (or their caregivers), is what keeps schools and childcare centers from having to temporarily close, sending kids home to their beleaguered parents.
Meanwhile, it is worth noting that Covid-19 hospitalization rates in very young children have worsened as of late—an example of two seemingly contradictory things being true at the same time. On one hand, most Covid-19 illnesses among toddlers indeed appear to be mild. On the other, the rate of hospitalization is probably a lot higher than most parents (and nihilist pundits who don't treat children) realize. Covid-19 is both less and more dangerous to unvaccinated young children than is commonly understood.
Recently, the CDC announced new testing guidelines for the general population, including recommendations for schools and daycares that seemed to imply that routine screening (i.e., asymptomatic testing) “might not” be cost effective, especially during times of low Covid-19 prevalence. While that’s different than saying that routine screening is not effective and that’s different from actually discouraging routine screening, that’s absolutely how many people have interpreted the CDC’s new statements. The reality is that many parts of the country are not experiencing anything like low rates of Covid-19. In such places, the CDC’s guidance actually suggests that that routine screening remains cost effective. Additionally, excellent modeling published in JAMA Pediatrics earlier this year found that weekly universal screening not only stands to reduce Covid-19 transmission among students and teachers, but it can reduce the costs associated with remote learning and hybrid classrooms. When routine testing is done, there is less Covid. The less Covid there is, the lower the need for remote learning is.
In sum, children ages 0-4 years old who acquire SARS-CoV-2 are often asymptomatic, but likely are still contagious. Early in the pandemic, some people thought (incorrectly) that children could not spread coronavirus. That was clearly wrong, and likely just reflected that the more extreme mitigation measures in place early on actually worked. So, given what we know about routine testing (i.e., that it keeps daycare and schools open, rather than just unearthing insignificant cases and unnecessarily consigning kids to isolation without benefit to them or their classmates), the case of continuing routine asymptomatic screening for daycares and preschools remains strong, if the goal is to maximize in-person days of care and learning.
Unfortunately, with government funding drying up, it may be harder for schools and care centers to provide regular testing for their communities—particularly poorer ones. That will mean more sick kids, more missed days of daycare and preschool, and more missed days of work—and the potential to get sick—for parents and caregivers. Keeping schools and daycare open continues to require effort and resources. But given the alternative, it’s worth it.
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