As the novel coronavirus continues to spread around the world, and scientists rush to develop a vaccine for the disease, questions have emerged around the effect it may have on children—and what their role could be in spreading it.
It is early days yet in the epidemic of Covid-19, as the disease caused by the coronavirus is officially known. Good data is hard to find and misinformation is spreading like wildfire. But a few initial studies show that children appear to be getting coronavirus at much lower rates—and with milder symptoms—than adults.
An analysis of 44 ,672 confirmed cases of Covid-19 in China released by the Chinese Center for Disease Control and Prevention and published in the Journal of the American Medical Association (JAMA) shows that, as of Feb. 11, fewer than 2% of cases (965 cases) occurred in children under the age of 19, compared to 87% in adults between 30 and 79 years old.
These numbers only reflect the situation in China; case rates in different age groups will reflect the overall age distribution in each country touched by coronavirus. In China, children under 19 account for 23% of the total population, compared to 62% for adults between 30 and 79.
Children in China also appeared less likely to die from the disease than adults: According to the JAMA study, no deaths occurred in kids aged 9 and younger, even though the overall case fatality rate was 2.3%. That number is still an estimate: In the last week of February, World Health Organization epidemiologist Bruce Aylward said the case fatality rate is between 2% and 4% in Hubei province, the origin point of the epidemic, and 0.7% in other parts of China.
There are two main scenarios that could explain these numbers in kids. The new coronavirus, SARS-CoV-2, may be less likely to infect children than adults. Or it could just be that children exhibit milder symptoms, or none at all, and are therefore less likely to seek medical care than adults. That could artificially deflate the number of cases in children. As the US Centers for Disease Control and Prevention (CDC) recently stated, “children with confirmed Covid-19 have generally presented with mild symptoms, and though severe complications…have been reported, they appear to be uncommon.”
“We just don’t understand whether children are getting infected at low rates or just not showing very strong symptoms,” said Marc Lipsitch, head of the Harvard T.H. Chan School of Public Health’s Center for Communicable Disease Dynamics, in an interview with the Harvard Gazette.
Even if children are less likely than adults to get or die from the virus that causes Covid-19, that doesn’t mean there’s no threat. First, children with underlying health conditions, like asthma, could have an increased risk of complications. And, as Helen Branswell and Meghan Thielking write in STAT News, “there’s reason to think kids may be helping to amplify transmission,” by “becoming ill and passing flu viruses on to their parents, grandparents, teachers, and caregivers,” who are more vulnerable than they are to the disease.
The CDC hasn’t provided any measures to protect against the virus that are specific to kids. Across the board, the agency recommends “cleaning hands often using soap and water or alcohol-based hand sanitizer, avoiding people who are sick, and staying up to date on vaccinations, including influenza vaccine.”
But there are ways in which this epidemic could uniquely affect children’s lives in the next few months, as some governments, worried about person-to-person transmission, enforce long-term school closures.
“The go-to intervention in flu pandemic planning is closing schools, and that may be very effective or it may be totally ineffective,” argues Lipsitch to the Harvard Gazette. “It’s a costly and disruptive thing to do, especially in the United States, because many people rely on school breakfast and lunch for nutrition. So we really need evidence that closing schools would help.”