Scientific knowledge about infectivity in children (under 18-19 years) remains rather vague. Some aspects are confirmed, while others are still contradictory.
During this new school year, especially due to the pandemic, schools, colleges and colleges have reopened. The measures have even been relaxed with new protocols. Minister of Health Olivier Véran justifies this by declaring that children ” have little risk of severe forms and are not very active in the coronavirus transmission chain If a child tests positive for coronavirus, this will no longer be the reason for the closure of the facility.
We are far from the first explanations from March 2020, when schools were closed completely from the first pollution by a student or teacher. It was then thought that there was a risk that the youngest were among the most important vectors in the coronavirus. This claim came from nowhere: the coronavirus was even newer than it is today, and many pathogens are known to spread by children. This is the case with flu epidemics, such as certain respiratory illnesses. This approach has been cracking for several months, but even at the end of September 2020, the coronavirus is still very new: if certain mechanisms in the coronavirus become clearer, security is not legion.
So what is the scientific basis for government decisions? These bases exist, but they are different and sometimes relatively contradictory. Nothing absolutely abnormal: scientific research cannot be found without searching, and searching is a long, complex process. Here we are right now when it comes to infectivity in children.
Studies with different conclusions
In France, a study based on 600 children in Île-de-France was presented, conducted by 27 pediatricians and led by Dr. Robert Cohen (Vice President of the French Pediatric Society) in June 2020. Press releases first via The Parisian, this work has been reprinted on the Medrxiv platform, which means that it has not yet been peer reviewed and published in a scientific journal. There are two main findings:
- Children would be less likely to be infected with Covid-19 disease, and even less severe forms, where the case of infection was largely asymptomatic;
- Children are said to be much less contagious than adults.
In Infovac’s professional medical newsletter, of which he is the author, Robert Cohen explains: ” Children are less often symptomatic, less often infected and less contagious than adults. Direct transmission between children or from child to adult is estimated to be low and in the vast majority of cases, infected children have been infected by an adult near them. However, the risk of indirect transmission via hands and objects is probably greater. The pediatricians in this study really showed that most of the children who were positive for the coronavirus in PCR were also serologically positive: they therefore already had antibodies, so the potential for infectivity is much lower.
The first result – the low proportion of children and adolescents among those affected by the SARS-CoV-2 coronavirus and the fact that the symptoms are less severe, with a majority of asymptomatic – begins to be treated. a significant amount of evidence to validate it. The studies are many and consistent (examples: 1, 2, 3). The fact that children are less seriously affected by the epidemic also explains why it is still difficult to study the specific infection mechanism in this population.
The second conclusion – about the low infectivity of children among themselves or towards adults – is currently more fragile, as it is still the subject of contradictory studies that do not reach the same conclusion. A German study (in repression, like the above-mentioned French study) provides elements in favor of a viral load that would be the same in adults and in asymptomatic children. The authors then write that “ the viral loads observed in the current study, in combination with previous results of similar attack rates between children and adults, suggest that the potential for transmission in schools and daycare centers should be assessed with the same assumptions about infectivity as for adults. »
South Korean research suggests another type of difference between age groups in children. In the October 2020 issue of the magazine Emerging Infectious Disease, South Korean researchers use contact trace analysis of 59,000 people over three months to show that children under 10 are less contagious than adults, but that children between 10 and 19 are closer to adulthood, would be as contagious as adults. A study published in July 2020 in the journal JAMA Pediatrics notes that children under 5 years of age may have a corresponding or even higher viral load than in adults. However, these researchers did not study the potential for infectivity associated with this viral load, so this is not necessarily inconsistent with the South Korean study.
Many uncertainties and a political choice
In August 2020, the European Center for Disease Prevention and Control (ECDC) published a comprehensive report on the situation of children before the coronavirus epidemic. This confirms that the infection is usually “in children milder or asymptomatic, which means that the infection may go unnoticed or not be diagnosed “. As regards infectivity, the ECDC report concludes that, given our current knowledge,” When they show symptoms, children shed the same amount of viruses as adults and are therefore contaminants as adults. The infectivity of asymptomatic children is unknown. »
Given the relatively different scientific studies on the infectious agent, it seems difficult to state anything as certain. In April 2020, the Scientific Council confirmed that “ there is great uncertainty about the role children can play in transmitting the virus », Recalls the weak scientific group on the subject. The members then recommended keeping the schools closed until September.
The choice of the French government to open schools is therefore a choice with socio-political aspects. And yes, it is true that these aspects obviously need to be taken into account. The lack of physical exercise is not without consequences for the youngest, as it does for parents’ family and professional life and therefore for the country’s activity. British researchers write with some relevance that ” decision to resume is a difficult compromise between epidemiological consequences and children’s emotional, pedagogical and developmental needs The latter also explains that in England the reopening in June seems to have increased the number of cases, but without causing a jump in the reproduction rate (and thus in the real increase in the epidemic).
France is not the only country that has chosen to rely on studies in favor of less contagion to resume schools. The Dutch website states, for example, that ” the spread of Covid-19 disease among children or from children to adults is less common “. It is not possible to know at this time whether this election is epidemiologically sound ahead of the second wave that is currently taking place in France.
The sequel in the video