Study: Children far less likely to contract coronavirus

A new study of coronavirus infections in six countries around the world show children are about half as likely to be infected as older people, and those who are infected only rarely show serious symptoms.

The study, published in the journal Nature Medicine by researchers from the Department of Infectious Disease Epidemiology at the London School of Hygiene and Tropical Medicine, found children under the age of 20 were half as likely to contract the coronavirus as those over the age of 20.

Among those who do contract the virus, only about 21 percent of children ages 10 to 19 who were infected showed clinical symptoms of COVID-19, the disease caused by the novel coronavirus. The percentage of older people who show clinical symptoms of the disease rises as ages increase. Among those over the age of 70 who contract the virus, almost 7 in 10 show symptoms.

The study examined coronavirus cases in China, Japan, Italy, Singapore, Canada and South Korea. It offers an early sign that school closures, a common intervention meant to stop the spread of a virus, may not be a major factor in slowing the spread of the coronavirus.

“Interventions aimed at children might have a relatively small impact on reducing SARS-CoV-2 transmission, particularly if the transmissibility of subclinical infections is low,” the authors wrote.

The authors speculate that children might have a built-in advantage that older people do not. In early stages of life, children are exposed to several other more ordinary types of coronavirus. Those coronaviruses may cause nothing more than a common cold.

But exposure to those viruses might prime a child’s immune system to be on the lookout for other types of coronaviruses that look similar — including SARS-CoV-2. In a sense, children who have been exposed to less deadly diseases might be better equipped to fend off the more deadly strain.

Scientists have sought to understand the role children play in transmitting the novel coronavirus in hopes of understanding how it might spread once schools are reopened. Many are concerned that even if the virus does not pose a danger to children, those children who are infected might go home and infect parents or grandparents, who are more at risk of suffering severe symptoms.

The authors cautioned that more data is needed to understand both how infectious and how dangerous the coronavirus is for children and the role even asymptomatic children might play in spreading the virus to other more susceptible populations.

But they found school closures had little impact on slowing the spread of SARS-CoV-1, the coronavirus that broke out in 2003 and caused severe acute respiratory syndrome.

Models constructed for the new study found school closures only reduced median peak COVID-19 cases by between 8 and 21 percent, depending on how infectious the virus truly is.