Schools have begun to reopen, but scientists are still trying to figure out how coronavirus affects children.
The role of children in the spread of coronavirus has been one of the main questions since the early days of pandemics. Now that some countries are allowing schools to reopen after a few closed weeks, scientists are trying to answer that question.
Children represent a small proportion of cases confirmed with COVID-19 – less than 2% of reported infections in China, Italy and the United States have been under 18 years of age. But researchers are divided on whether children are less likely than adults to become infected and spread the virus.
Other scientists argue against a hasty return to classes. They say the chance of infection in children is lower than in adults in part because they have not been exposed to the virus so much – especially as many schools have been closed. And children are not being tested as often as adults because they tend to have mild symptoms or not show up at all, the researchers say.
“I don’t see any strong biological or epidemiological reason to believe that children don’t get infected so much,” said Gary Wong, a researcher in pediatric medicine at Hong Kong Chinese University. “As long as there is a transmission of the virus in the adult population, reopening schools is likely to facilitate transmission, as it is known that respiratory viruses circulate in schools.” He says there should be surveillance systems and tests before schools open.
If children spread the virus, the infections will certainly increase in the coming weeks in places where children have already returned to school, scientists say.
Even less understandable is if infected children spread the virus in the same way as adults.
A study conducted in the French Alps observed a nine-year-old who attended three schools and a skiing class as he had symptoms of COVID-19 but did not infect any single person. “It would be almost unheard of for an adult to be exposed to so many people and not infect anyone else,” says Munro.
Kirsty Short, a virologist at the University of Queensland in Brisbane, Australia, conducted a meta-analysis of several home studies, including some of the places that had not closed schools at the time, such as Singapore. She found that children are very rarely the first person to bring the infection into a home; they were the first in only about 8% of households.
“Home studies are safe because even if there are a lot of infected children, when they go home they don’t infect others,” says Munro.
But Wong argues that such a study is one-sided because the families were not randomly selected, but were chosen because there was already an adult there who was known to be infected. So it is also very difficult to determine who introduced the virus, he says.
Based on the evidence, Munro says children should be allowed to return to school. “Children gain less from obstacles, and have more to lose,” such as lack of education.