Research finds older children just as likely to transmit coronavirus as adults

  • While there are debates in SA about whether schools should remain open, the question is whether children can transmit the virus as much as adults.
  • A large study from South Korea investigated primary transmitters and their contacts in several households.
  • Children younger than 10 were less likely to transmit coronavirus, while older children were just as likely as adults to infect others.

As pressure mounts in South Africa to close schools once again, there is much debate whether children are as likely as adults to transmit SARS-CoV-2, the virus that causes Covid-19.

Now a large study from South Korea, published in Emerging Infectious Diseases, suggests that, while children younger than 10 are less likely to transmit the virus, older children between the ages of 10 and 19 have the same capacity to spread the virus as adults.

According to these findings, there may be a surge of Covid-19 cluster outbreaks in communities as schools reopen.

Rigorous analysis

While previous studies showed children and teenagers are less likely to spread Covid-19 than adults, these studies were "small and flawed", according to Dr Ashish Jha, director of the Harvard Global Health Institute.

Dr Jha told the New York Times this new study was systematic, carefully done and encompassed a large population. According to other experts, the scale and rigour of this analysis was praiseworthy.

Contact tracing key

The South Korean researchers identified 5 706 people who first reported symptoms of Covid-19 in their households between 20 January and 27 March 2020 while schools in the region were closed. They then traced 59 073 people these families had contact with.

All household members of patients were tested for symptoms, but outside the households, only those with symptoms were tested.

The researchers were aware that those who first developed symptoms in a household were not necessarily the first to be infected, and children were still less likely than adults to show symptoms. This means the research might have underestimated the number of children who could have transmitted Covid-19 in their households.

But experts agree that this method of contact tracing was still feasible, despite its limitations.

Why are children younger than 10 less likely to spread Covid-19?

This study was consistent with other studies in pointing out that children younger than 10 are less likely to transmit the virus than older children and adults.

The reason for this is most likely that children exhale less air, which means fewer respiratory drops that contain viral matter. The air they exhale is also closer to the ground and not in the direct "firing line" of adults. But older children are roughly the same height and size as adults, but are not necessarily as likely to adhere to the hygienic and physical distancing measures mandated at school.

Even though this large study provides more insight, there is still uncertainty about to what extent children may cause Covid-19 cases to surge when schools reopen.

"I fear that there has been this sense that kids just won't get infected or don't get infected in the same way as adults and that, therefore, they're almost like a bubbled population," infectious diseases researcher Michael Osterholm from the University of Minnesota, who wasn't involved with the study, told The New York Times.

"There will be transmission. What we have to do is accept that now and include that in our plans."

READ: Can children spread the new coronavirus? The science is still unclear

READ: How lockdown could affect South Africa's children with special needs

READ: Cough may not be key symptom of coronavirus infection in children

Image credit: Getty Images

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