Via Nature.com: Coronavirus latest: children are as susceptible as adults, study suggests. Excerpt and then a comment:
Here’s the latest news on the outbreak.
5 March 15:30 GMT — China study suggests children are as likely to be infected as adults
Children are just as likely to get infected with the new coronavirus as adults, finds one of the most detailed studies yet published on the spread of the virus, known as SARS-CoV-2. The analysis — based on data from Shenzhen, China — provides a partial answer to one of the most pressing questions surrounding the outbreak: the role of children.
Previous studies have suggested that kids were far less likely to develop severe symptoms when infected by the coronavirus, compared with other age groups. But it was not clear if it was because they weren’t getting infected or if they were fighting off the infection more effectively than others.
“Kids are just as likely to get infected and they’re not getting sick,” says Justin Lessler, an infectious-disease epidemiologist at Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. He co-led the study with Johns Hopkins epidemiologist Qifang Bi, and epidemiologists Ting Ma, at the Harbin Institute of Technology in Shenzhen, and Tiejian Feng, of the Shenzhen Center for Disease Control and Prevention. They posted the analysis to the medRxiv preprint server on 4 March.
The study is unique in that it looked at not only people who were infected with the virus, but also large numbers of their close contacts, some of whom were infected and many who were not. The researchers followed 391 people who were diagnosed based on their symptoms, and 1,286 of their close contacts to see whether they tested positive for the virus even if they didn’t show symptoms. Overall, the team found that children under 10 who were potentially exposed to the virus were just as likely to become infected as other age groups, with about 7 and 8% of contacts of known cases later testing positive.
They also found that people who lived in the same household as an someone infected with the virus — and came into close contact with them — were about six time mores likely get infected, compared with people who made contact with an infected person in other settings.
“This may be the first clear evidence that children are as susceptible as adults to SARS-CoV-2 infection,” says Ben Cowling, an infectious-disease epidemiologist at the University of Hong Kong. He now wonders whether the fact that outbreaks haven’t been observed in schools could be down to the fact that children’s symptoms are mild.
Lessler says it’s still not clear whether children are important in transmitting the virus, as they are with influenza, where children routinely develop symptoms and are common hubs in chains of transmission. “That’s one of the current critical remaining questions and we’re trying to figure out how to answer,” he says. “I have a 7-month-old and a 6-year-old and I can’t imagine that, if they have any virus at all, they're not getting it on somebody.”
This reminds me of the days when I used to teach students in my college's early childhood education program. The students spent their days in daycares and their evenings in class, and they often came in with terrible colds—a well-understood occupational hazard of the profession. The idea of toddlers and other children as efficient COVID-19 spreaders is not a reassuring one.