“Super-contaminants”. This expression was used at the start of the coronavirus epidemic to refer to children. If the latter seemed less seriously affected by Covid-19 than adults, some data pointed to their decisive role in the transmission of the virus. Since then, research has minimized this role. But a new study published in the journal JAMA Pediatrics confirms the important role of children in the spread of the coronavirus.
10 to 100 times more genetic material of the virus in children
To reach this conclusion, the researchers followed three groups: the first consisted of 46 children under the age of five, the second consisted of 51 children and adolescents aged 5 to 17, and the last of 48 adults aged 18 to 65 years. All of the participants tested positive for Covid-19.
To assess the level of genetic material in each participant, they were subjected to PCR tests, which involves taking cells from the back of the nose using a swab. As a result, the level of genetic material of the virus in the noses of children under five was 10 to 100 times higher than that found in older children and adults.
“Our analyzes suggest that children under 5 with mild to moderate Covid-19 have high amounts of Sars-CoV-2 viral RNA in their nasopharynx compared to older children and adults.”, explain the researchers. “Thus, young children can potentially be factors of propagation of Sars-CoV-2 in the general population “, they conclude.
Contagiousness of children: a subject that is still debated
But the question of the contagiousness of children is still debated. A study conducted in Ile-de-France by 27 pediatricians from April 14 to May 12 on 605 children and revealed by The Parisian last June revealed that up to the age of 15, children are not very contagious. Even more surprising: it is adults who transmit the coronavirus to them, and not the other way around!
To find out, the 605 children in the study were subjected to diagnostic tests for the coronavirus: a PCR test and a serological test, which involves drawing blood to detect the presence of antibodies, indicating that a person has already been contaminated. Results? Serological tests revealed that 10.7% of children screened had already been affected by Covid-19. PCR tests, meanwhile, indicated that 1.8% of children were carriers of the coronavirus. But that’s not all: only 0.6% of them were contagious.
Findings which confirm not only that children are less affected by Covid-19, but also that they transmit the virus little. To explain these two phenomena, Dr. Robert Cohen, pediatrician, infectious disease specialist and co-author of the study, provided several leads to Parisian : children have fewer virus receptors on the nasal mucosa, which limits the risk of contamination. They also defend themselves better than adults against infections because they are often exposed to them (cross-immunity), but also because they have a constantly runny nose (trained immunity). And if children transmit the virus little, it is partly because their saliva droplets do not reach the height of adults, due to their small size.
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