While the debate over reopening schools is raging in several countries, many unknowns remain about Covid-19 in children, especially their ability to transmit the disease. An update on what we know and what we don’t yet know.
What are the risks for children?
“There are three key questions: what is the level of infection in children, how serious is the disease in them, and are they spreading it to others. Only the second one has good data, “said Professor Russell Viner, president of the Royal College of British Pediatrics.
These data show that the severe forms of Covid-19, and a fortiori the deaths, are exceptional in children.
Worldwide, “critical forms of the disease in children appear to be very rare (around 1% of the total)” and “only a handful of deaths have been reported,” according to Don’t Forget The Bubbles ( DTFB). This British pediatric site has analyzed all the studies on the subject.
The risk for children of becoming seriously ill by finding their friends when schools reopen therefore seems low.
What level of infection?
It is more difficult to say whether children are as likely as adults to get the disease. The WHO judges that “children and adolescents are as likely to be infected as any other age group.”
However, the pediatric cases of Covid-19 represent only “a small part (1 to 5%) of all the cases reported in the world”, according to the French health agency Santé publique France, which published on its site a synthesis of international studies on the subject.
According to her, this comes from the fact that the majority of children infected with coronavirus have “mild” forms of the disease, even without symptoms at all, which makes them more difficult to detect.
Conversely, other experts believe that children, especially those under the age of 10, are less likely to get Covid-19 than adults.
On the Don’t Forget The Bubbles site, two pediatric specialists, Alasdair Munro and Damian Roland, believe “it is more and more likely that fewer children will be affected by Covid-19” than adults.
They are based on tests carried out massively in South Korea, Iceland or the Italian city of Vo, where the number of positive children was much lower than that of the adults.
Are they vectors of the epidemic?
She’s the big stranger. The latest data suggests that children transmit SARS-CoV-2 less than adults, contrary to what was initially believed by analogy with other viral diseases, including the flu.
Several studies support this hypothesis, although there is still no certainty. One of them relates to one of the first outbreaks observed in France, starting from a chalet in Haute-Savoie.
Among the sick was a 9-year-old child. However, he did not contaminate anyone, not even the other two members of his siblings, even though he had been in contact with 172 individuals, including 112 students and teachers. However, he transmitted other winter viruses that had also infected him, including the flu virus.
However, a German study posted online on April 29 th cast doubt. Led by virologist Christian Drosten, counselor to Angela Merkel, it concludes that children infected with the new coronavirus have a viral load comparable to that of adults and “could be as contagious” as they are.
But other scientists, including Alasdair Munro and Swiss epidemiologist Leonhard Held, have challenged the methodology and the conclusion of the study. By re-analyzing their results, they even lean more towards the opposite interpretation and a lower viral load than adults.
In addition, viral load is not the only criterion. The contagion of children could be less due to “the fact that they have no symptoms and do not cough,” said French expert Arnaud Fontanet on April 30 at a parliamentary hearing.
“We have a bunch of arguments that suggest that in children under 10 the situation is probably less severe than in adults, namely that they are probably less susceptible to infection and less contagious. But we want to be able to verify it, ”he added.
To do this, he is conducting a study with children from six primary schools in Crépy-en-Valois, a French commune very affected at the start of the epidemic, to “find out if they were infected during the epidemic period of February”. Other similar work is underway elsewhere in the world.
A new inflammatory disease?
In the past two weeks, several countries have reported cases of children affected by an inflammatory disease with symptoms close to a rare condition, Kawasaki disease.
The link to Covid-19 has not been formally established, but scientists believe it is likely. A few dozen cases have been reported in New York, France, the United Kingdom, Italy or Spain. Symptoms are high fever, abdominal pain and digestive disorders, rash, followed in some cases by heart failure.
In an article published online Wednesday by the medical journal The Lancet, British doctors describe the first 8 cases observed in London. They hypothesized a “new phenomenon affecting children who previously had no symptoms, and in whom SARS-CoV-2 infection manifests as hyperinflammatory syndrome”.
It could be a runaway immune system in some children a few weeks after being infected with the virus. Affected children respond well to treatment. These cases made an impression and rekindled fears among some parents before the schools reopened. However, specialists insist that they are rare.
“Having this weak signal on Kawasaki syndromes does not jeopardize the opening of schools,” said French virologist Bruno Lina on April 29 during a parliamentary hearing.
Should we reopen schools?
Scientists are divided on the issue. In Italy, the Higher Institute of Health (ISS) believes that this would “immediately” start the epidemic, and Prime Minister Giuseppe Conte has repeatedly insisted on the risk of infecting teachers. Italy has the oldest faculty in the OECD countries and almost 60% of the teachers are over 50.
Conversely, several countries have or will reopen their schools after a period of confinement, including Belgium, Germany, Denmark or France. The scientific committee which advises the French government had estimated at the end of April that the schools should be closed until September if one considered the strict point of view sanitary.
But “there are other elements to take into account”, such as social issues, had recognized AFP its president, Jean-François Delfraissy, citing the example of children from families in difficulty for whom ” school can be a haven of peace ”.
The bodies representing French pediatricians have also supported the reopening of schools, while respecting barrier measures and distancing.
“Children aren’t super-transmitters of Covid-19, it’s time to go back to school,” argued Alasdair Munro and another British infectious disease specialist Saul Faust in a column published by the journal Wednesday Medical Archives of Disease in Childhood.
For them, the benefits of going back to school for children far outweigh the risks. From an epidemiological point of view, conducting studies on children at the reopening of schools will make it possible to remove certain unknowns about their contagiousness.
“As many schools will reopen in Europe, the impact of their closure and reopening (on the epidemic) will become apparent,” notes Keith Neal, emeritus professor of epidemiology of infectious diseases at the University. from Nottingham (England). An impact that could also be linked to the fact that parents will inevitably be more involved in taking children to school.