We've summarized the good, the bad, and the caveats from 3 studies on pediatric cases of coronavirus worldwide (Originally published 6/8/2020)
The Bad News
In short -- yes. According to the Mayo Clinic, “children under age 1 (infants) are at higher risk of severe illness with COVID-19”(1). Young babies’ facial bones are structured so their airways are much shorter and more cramped than those of adults (2: photo). This, and the fact that their immune system is just starting to develop its own defenses, are two reasons babies are so vulnerable to respiratory infections. Normally you’d be focused on preventing common colds and the flu, but unfortunately, we 2020 parents have a pandemic respiratory illness to worry about, too.
In three studies of pediatric cases of COVID from China (3), Italy (4), and the US (5) published this year, babies under 1 year old were the most vulnerable of all child age categories. Children with underlying conditions were also reported to be highly vulnerable in the Italy and US studies. In the Italy study, 2-6 year olds were only 30% as likely to get COVID as children below 1 (4). Infants were also hospitalized most often: 20% of babies in the US study and 36.6% of babies in the Italy study were admitted to the hospital for their symptoms.
Image from Principles of Emergency Medicine, Edited by S. V. Mahadevan, Stanford University School of Medicine, California, Gus M. Garmel, 2012. Publisher: Cambridge University Press
The Good News
It’s not all bad, though. The percentage of COVID cases that were reported in children is lower than the percentage of the population that are children in all three studies (see our table). In other words, if the virus infected people of all ages equally, and children make up 22% of the US population, we would expect 22% of COVID cases to be in children. This is not the case, so kids in general are less likely to get sick.
Furthermore, symptoms are less severe in children than in adults overall. In the US, 71%, 80%, and 43% of adults had a fever, cough, or shortness of breath, respectively, while only 56%, 54%, and 13% of children experienced the same symptoms (5). And even though babies under 1 were the most at risk among pediatric groups, only 1.9% of infected babies in the China study and 0.9% in the Italy study had symptoms described as “critical” (3,5). In fact, 56.1% of infants in the China study and 40.2% in the Italy study were either asymptomatic or in the lowest level of symptom severity.
*Age <15, data from Wikipedia: https://en.wikipedia.org/wiki/Demographics_of_China
We should note that in the middle of this global emergency, the data are going to be a little messy. Data collection can be complicated by the flurry of activity in hospitals where it’s gathered as healthcare workers are overwhelmed by both patient care and paperwork. Definitions of disease vary and the virus mutates, over time and region by region. And as scientists, we know that every analysis has its faults. Each of these studies notes their specific limitations, which you can see in the links to the articles provided (contact us if you can’t access them!) All three reported incomplete records for at least some of the analyses, for example, though all had a fairly large n (number of subjects in their analysis) for the figures we’ve reported here. It's also possible in all 3 studies that children with more severe symptoms were more likely to be tested, or that children classified as "presumed" cases had symptoms that could be attributed to another upper respiratory disease.
That being said, it seems that the results of these 3 studies are in general agreement with each other, and for that reason I have faith in the conclusions we can draw from them. Fortunately, as this pandemic unfolds, we have a global army of epidemiologists and statisticians doing the hard work to unravel the underlying mechanisms and patterns of the viral spread. This scientist mama is grateful for their insights and looks forward to further clarification as the situation unfolds.
Among children, babies under 1 year old are the most vulnerable
BUT children are far less likely than adults to get COVID
Babies under 1 are more likely to have severe symptoms and a high hospitalization rate compared to older kids
BUT in general, pediatric symptoms are less severe than adult symptoms, even in infants