Donald Trump’s claims that children are “almost immune” to COVID-19 and that their immune systems are “much stronger against the disease” led Facebook to censor a video of the American president for disinformation.
The term “almost immune” is vague from a scientific point of view. What studies have confirmed since the beginning of the pandemic is that children are at low risk of becoming seriously ill from COVID-19, and are probably less likely to become infected.
But there is no consensus on the level of contagiousness of children who contracted the virus, even asymptomatic ones, a crucial question at a time when the beginning of the school year is approaching in the United States and other countries.
Minors under 18 represent about 2% of hospitalizations and much less than 0.1% of deaths related to COVID-19 in the United States, according to the Centers for Disease Prevention and Control (CDC), while representing 22% of the population.
45 infant deaths have been attributed to the coronavirus since February in the United States, against 105 to the common flu, of the 13,000 deaths recorded from all causes in this age group.
A study carried out in China at the beginning of the pandemic with 2,143 cases shows that 94% of children had no symptoms or had mild or moderate symptoms (infection of the lungs, fever, cough without difficulty breathing).
Children who become seriously ill usually appear to have a medical history. In Chicago, the 10 children hospitalized in March and April had pre-existing conditions or some other infection.
This does not mean that they are immune to the virus, as revealed the emergence, although unusual, of a serious inflammatory disease.
A thousand cases of this new “multisystemic inflammatory syndrome” have been identified in children worldwide, with a 2% mortality rate. Six children died in the United States, according to the CDC.
– What is debated: are children less infected? –
The question is: do children get less sick because their organisms fight infection better or because they are less contaminated by the coronavirus?
The official number of cases is not representative of the actual number of infected children, because the tests prioritized patients with symptoms, among which children are underrepresented.
But several reliable studies lean more towards the second hypothesis: the virus seems to infect children less, especially those under 10.
Diagnostic testing campaigns in Iceland, Spain, Geneva, Switzerland, or in the village of Vo, Italy, collected representative samples of the population to see the rate of people infected or who developed antibodies to the coronavirus: children were proportionally less infected than adults.
The scientific community, however, has not yet reached a consensus.
In the United States, a study was started in May with 2,000 families to discover the real impact of COVID-19 on children.
“We must have answers, with a good analysis, from the end of December this year,” recently declared Anthony Fauci, director of the National Institute of Infectious Diseases in the United States.
This is a valuable question as to the beginning of the school year in much of the world approaches.
If children, even with few or no symptoms, are as contagious as adults, then they could be great vectors and contaminate teachers, bus drivers, families …
The problem is that assessing a person’s contagiousness is not an easy task.
The first method is to look at viral load or virus concentration. A study of 145 children in Chicago showed that children under 5 had 10 to 100 times more virus particles in their nose, compared to older children and adults.
Theoretically, it would mean that they expel more viruses into the air with each exhalation and, as a result, infect more people around them. But if this is true for other viruses, it has not yet been proven for SARS-CoV-2.
The other method is epidemiological.
On the one hand, major outbreaks of COVID-19 emerged at a summer camp in Georgia, in the United States, or at a school in Jerusalem, which shows that the virus can actively circulate among young people.
On the other hand, a large study in South Korea has shown that children, especially younger ones, rarely infect their family members.
One of the first outbreaks in France, which started in a chalet in Haute Savoie, infected a 9-year-old child who, despite having had contact with 172 other people afterward, did not infect anyone.
Experts also call for distinguishing small children from adolescents, in whom the virus appears to behave more like adults.
Finally, immunologists are investigating another hypothesis: what if the four common human coronaviruses that cause colds provide immunity against COVID-19? Children usually have a cold, which would explain that they are relatively safe from the pandemic. The theory, however, still needs to be scientifically proven.