Children enter an elementary school (illustration). –
- Schools will reopen on May 11, causing concern for many parents.
- Initially presented as important vectors of the coronavirus, children would ultimately be little contaminated and little contaminant, according to several studies.
- But respect for barrier gestures will remain in order.
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They would not be that contaminating after all. Whereas at the beginning of the coronavirus epidemic, children were described as a public largely vector of transmission, this would not be the case, reassure the scientists. Good news, since the children have to go back to
school starting May 11th. Finally, on the basis of parental volunteering, specifies this Thursday the Elysée, while many
families do not hide their concern.
However, at the beginning of March, “our children and our youngest ones, according to scientists (…), are those who spread, it seems, the most quickly the virus”, had declared the president Macron to justify the closing of the schools. So what role do children ultimately play in the epidemic? Are they particularly at risk or contagious? Can we send them back to school without risking relaunching the epidemic? A study, published in April in the journal of the Society of American Infectious Diseases (Clinical Infectious Diseases), concludes that they are not important vectors of the disease.
“A different dynamics of transmission in children”
This study focuses in particular on the case of the 9-year-old child who had contracted Covid-19 in Contamines-Montjoie (Haute-Savoie), one of the very first French infectious foci. At the end of January, a Briton returning from Singapore had joined compatriots in the ski resort, including a family resident of the resort. Infected, it was the source of contamination of twelve people, including this 9-year-old child. The little boy, who continued to attend three schools and a ski club before the health alert was issued, eventually started mild symptoms of the coronavirus, with a very low viral load eight days after the first symptoms.
After an on-site investigation, infectious disease specialists and epidemiologists established that this young patient had been in contact with 172 people, including 112 students and teachers, while he was sick. All were then placed in quarantine at home because they were considered to be at high risk. But ultimately, this child did not infect anyone, not even the other two children of his siblings. The case “suggests that children may not be a significant source of transmission for this new virus” and suggests “a different dynamics of transmission in children”, the study concludes. While they are an important vector for other viruses like the flu, for example. “We know that when it comes to seasonal flu epidemics, children – and therefore schools – play a major role in the spread of the virus,” confirms Professor Arnaud Fontanet, director of the epidemiology unit for emerging diseases of the Pastor Institute. With the coronavirus, the role of children in transmission is not the same. “
Children “little involved in infectious foci”
Presumably, “it is possible that children, because they do not have many symptoms and have a low viral load, transmit little of this new coronavirus”, explains Kostas Danis, epidemiologist at Public Health France and principal author of this study.
If we know today that children “develop mild forms of Covid-19, we also now know that they are little involved in infectious foci,” describes Professor Fontanet. They usually keep the virus in their throat for about a week. But it has been observed that they are forms of “dead ends” of the virus: they are infected by adults – and not vice versa – and will hardly transmit the virus thereafter. This suggests that children are probably less infected and less infectious. ” And more precisely “children under 10”, who could be “less susceptible to infection, observed this Thursday on France 2 Professor Anne-Claude Crémieux, doctor specializing in infectious diseases at Saint-Louis hospital, in Paris. The results of work in progress are awaited on this point “, since this study, carried out on a single child, must be confirmed by other field surveys.
The fact remains that “it will be necessary to accompany the reopening of schools with a certain number of precautions,” insists Professor Fontanet, who recalls that “we are very far from collective immunity, so barrier actions must be respected by all”.
What about adolescents?
But what about adolescents? The Institut Pasteur conducted an epidemiological study carried out using antibody detection tests in a high school in Crépy-en-Valois (Oise), within an epicenter of the Covid-19 epidemic in France . This work, published this Thursday, reveals that 41% of high school students, teachers and staff working in this school were infected by Covid-19 in February-March. And only 11% of the relatives of high school students (parents and siblings) had antibodies against SARS-CoV-2.
Contaminated adolescents would therefore not have reported the virus massively at home, since intra-family contamination does not appear so frequent. “The risk of being infected in the home rose from 9% to 17% for parents if the student was infected, and from 3% to 21% for siblings,” the researchers observe. But “high school students are closer to adults for the ability to transmit the virus than to children,” says Professor Fontanet, the study’s first author.
To date, we know that in China, Europe or the United States, people under the age of 20 represent between 1% and 2% of confirmed cases. And many undiagnosed cases have developed mildly or not symptomatic forms. Thus, “at least 17% of people infected in Crépy-en-Valois did not have symptoms,” said Professor Fontanet. And “the proportion of asymptomatic patients is between 17 and 40%,” said Dr. Simon Cauchemez, head of the Mathematical Modeling of Infectious Diseases unit at the Institut Pasteur. A proportion probably higher in the youngest, and which does not enter the screening criteria provided in the context of progressive deconfinement, which plans to reserve the tests for patients with symptoms of Covid-19. “We will never be able to test everyone,” says Dr. Cauchemez. In order to identify asymptomatic patients despite this, “it will be necessary to detect contacts who, for their part, could present symptoms,” he advances. The screening of those around them will allow these patients with little or no symptoms to be captured and isolated. “
In France, according to figures released by Santé publique France on April 7, out of 29,721 people hospitalized, there were 110 children under the age of 15.
