Researchers in Boston followed 192 children aged 0 to 22, of whom 49 tested positive for SARS-CoV-2, and 18 developed a late form of COVID-19. Analyzes show a significantly higher viral load in the respiratory tract in these children than in adults hospitalized in intensive care units (ICU) for COVID-19.
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High levels of the virus in COVID-19 children of all ages
This observation is commented on by the main author, Dr Lael Yonker, director of the MGH Kystic Fibrosis Center, who notes in these children, a particularly high load during the first 2 days of infection: “I didn’t expect the viral load to be this high. You think of a hospital and all the precautions taken to treat critically ill adults, but the viral loads of these hospitalized adult patients are significantly lower than those of an asymptomatic, “healthy” child walking around with SARS- CoV-2“.
The risk of contagion from children is therefore higher than expected: because the transmissibility is higher with a high viral load. Simultaneously with viral load, researchers looked at viral receptor expression and antibody response in healthy children, children with acute SARS-CoV-2 infection, and smaller numbers. of children with multisystem inflammatory syndrome (MIS-C), a disease with characteristics similar to those of Kawasaki disease and often diagnosed in children and adolescents with COVID-19.
Not very symptomatic but strongly propagating? The results of nose and throat swab tests (PCR) and blood samples (serologies) confirm that children are not immune to this infection and that their symptoms do not correlate with the degree of exposure and severity of infection. “Our results show”, write the authors in their press release, “that children are not protected against the virus and that they can play a key role as potential propagators of this virus”. Because analyzes and evaluations confirm that if COVID-19 children are not as likely to develop forms as severe as adults, as asymptomatic or low-symptomatic carriers attending school, they can very well spread the infection. and introduce the virus into their home.
A particular concern for families, in particular belonging to certain socio-economic groups, more severely affected by the pandemic, as well as for multigenerational families with vulnerable elderly people at home: thus, in this study, 51% of children suffering from an acute infection by SARS -CoV-2 were from low income communities compared to 2% from high income communities.
The low number of receptors for SARS-CoV2 in children, has “nothing to do” with the viral load: this is another decisive finding of the study: the researchers dispute the current hypothesis according to which, as children have a lower number of immune receptors for SARS -CoV2, they would be less likely to be infected or seriously ill. Data from the group shows that although younger children have fewer receptors for the virus than older children and adults, this low number of receptors does not correlate at all with a decrease in viral load:
Children can carry a high viral load, which means they are more contagious.
and this regardless of their susceptibility to developing a COVID-19 infection.
Severe complications in children with MIS-C: When researchers study the immune response in MIS-C, a systemic “multi-organ” infection that can develop in children with COVID-19 several weeks after infection, they see, in some cases, disorders or even severe heart shock and / or failure: ” this is a serious complication due to the immune response to the COVID-19 infection, the number of these young patients is increasing and as in adults who develop these very serious systemic complications, the heart appears to be l ‘organ targeted by the post-COVID-19 immune response’. Further research is essential to better understand MIS-C and post-infectious immune responses in pediatric COVID-19 patients, the authors say.
The most critical question is what measures schools will implement
«to ensure the safety of children, teachers and staff ”.
On this point, the authors focus on infection control measures, including
- social distancing,
- use universal the mask,
- effective hand washing protocols,
- and a combination of distance and face-to-face learning.
- They also consider that screening systematic and continuous of all students for SARS-CoV-2 infection with communication of results in time real is an imperative part of a safe back to school policy.
“Children are a possible source of the spread of this virus, and this should be taken into account in the planning stages for the reopening of schools. If schools reopen completely without implementing the necessary precautions, it is likely that children will play a larger role in this pandemic ”, conclude the authors.
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