US research: children can carry a lot of coronavirus

Children can have many particles of the coronavirus in their nose even if they have no symptoms or are just a little sick. This makes them a potential source for further spread of the virus. Because the absence of disease symptoms is not a reliable indication of whether children have and can spread the virus, infection prevention measures are needed when reopening schools.

That’s what scientists associate with a number of hospitals and scientific institutions in Boston, including the Harvard Medical School. They recently published their findings in The Journal of Pediatrics.

The Dutch paediatrician and epidemiologist Patricia Bruijning of the UMC Utrecht is not very impressed. “I know the study but I don’t think it’s very relevant to the reopening of schools.” Bruijning finds the research group – children who come to the hospital with a suspicion on covid-19 – “a very selected group and probably not very representative of the average teenager”. After all, “the sicker you are, the greater the amount of virus particles you have”. According to Bruijning, “the study adds very little to what already knew”.

‘What you’d expect’

The American researchers included 192 children in their study, 49 of whom had a confirmed SARS-CoV-2 infection. Eighteen had the serious condition MIS (Multisystem Inflammatory Syndrome), which is associated with covid-19 in some children and not in others. The remaining 125 children were tested negative for SARS-CoV-2.

“That is exactly what you would expect,” says Bruijning. “Because in people who have complaints for more than seven days, the amount of virus particles is usually a lot lower than at the start of the infection. As far as I’m concerned, it’s a nonsensical equation.”


“We do not yet know exactly what this relationship is like for young children. But it is possible that they bring less virus into their environment than an adult with the same amount of virus due to a lower breathing volume and lower rates of exhalation. That’s an open question that needs to be investigated further.”

The American study is not about the contagiousness of children, the scientists write. But “children with high levels of virus particles and non-specific symptoms such as colds and coughs can probably transmit SARS-CoV-2 just as easily as other viral infections that are spread through droplets. If schools completely reopen without the necessary precautions, children are likely to play a greater role in this pandemic.”

Infection prevention

“In order to control the infection, it is essential to identify infected children as early as possible with a view to quarantine,” the researchers write. But according to the American scientists, this is difficult because about half of the children have no symptoms or are very mild. Especially now that the schools are reopening, they see this as a cause for concern

“Infection prevention measures should minimize the risk of spreading the virus. The focus should be on strategies involving social distancing precautions, the use of nasal masks and/or remote education” Furthermore, according to the authors, schools could routinely test their pupils for SARS-CoV-2.