Science

Covid-19: do we really have to reopen schools, colleges and high schools, according to science?

While middle and high school students can be – albeit moderately – vectors of the Covid-19 virus, this is not the case for children under the age of 10, many studies show. By virtue of these data, most experts speak out against the closure of primary and kindergartens, and recall that the school environment is not an essential lever for controlling the pandemic. However, it remains to protect secondary school teachers, twice as affected by the disease as their counterparts in distancing.

Little or no impact of 0-9 year olds on the epidemic

To judge the impact of children and the closure of schools on the Covid-19 pandemic, the best way is to observe the countries whose schools were reopened before ours. This is the case in Israel, where schools were reopened on November 1, 2020. Researchers there examined the infection rates of 0-19 year olds compared to other age groups, in a study published in the JAMA Network Open. “Children aged 0 to 9 did not have substantial rates of infection with SARS-CoV-2 (Covid-19 virus, editor’s note) during periods of school attendance, and it can be assumed that they did not. also not played a significant role in the spread of Covid-19 during this period“, the authors conclude in the publication. Therefore, returning to school for this group appears to have been safe. In contrast, 10-19 year olds had similar infection rates to adults.”It is probably safer to return to school for young people aged 10 to 19 only when the epidemic is under control and after measures to reduce the spread in schools are implemented.“, conclude the researchers.

Circulation in children reflects the situation in the general population

At a time when the circulation of the virus is increasing in the general population, the increase also observed in children is only a reflection and not the cause. Proportionately, children remain less infected than adults, even with variants“, explains the French Society of Pediatrics end of March 2021.

Thus in New South Wales (Australia), out of 1,411 contacts identified in schools, only five (0.4%) cases of infections (three children / adolescents and two teachers) were recorded over two quarters, i.e. one case every 282 contacts, according to a study published in the Lancet Child & Adolescent Health.

that moderately – vectors of the Covid-19 virus, this is very little the case for children under 10 years old, show numerous studies. By virtue of these data, most experts speak out against the closure of primary and kindergartens, and recall that the school environment is not an essential lever for controlling the pandemic. However, it remains to protect secondary school teachers, twice as affected by the disease as their counterparts in distancing.

Little or no impact of 0-9 year olds on the epidemic

To judge the impact of children and the closure of schools on the Covid-19 pandemic, the best way is to observe the countries whose schools were reopened before ours. This is the case in Israel, where schools were reopened on November 1, 2020. Researchers there examined the infection rates of 0-19 year olds compared to other age groups, in a study published in the JAMA Network Open. “Children aged 0 to 9 did not have substantial rates of infection with SARS-CoV-2 (Covid-19 virus, editor’s note) during periods of school attendance, and it can be assumed that they did not. also not played a significant role in the spread of Covid-19 during this period“, the authors conclude in the publication. Therefore, returning to school for this group appears to have been safe. In contrast, 10-19 year olds had similar infection rates to adults.”It is probably safer to return to school for young people aged 10 to 19 only when the epidemic is under control and after measures to reduce the spread in schools are implemented.“, conclude the researchers.

Circulation in children reflects the situation in the general population

At a time when the circulation of the virus is increasing in the general population, the increase also observed in children is only a reflection and not the cause. Proportionately, children remain less infected than adults, even with variants“, explains the French Society of Pediatrics end of March 2021.

Thus in New South Wales (Australia), out of 1,411 contacts identified in schools, only five (0.4%) cases of infections (three children / adolescents and two teachers) were recorded over two quarters, i.e. one case every 282 contacts, according to a study published in the Lancet Child & Adolescent Health. However, this region accumulated only 4,000 cases of Covid-19 out of 8 million inhabitants in November 2020, or 41 times more than in France, which accumulated at the same time almost 1.5 million cases. At school, the transmission of Covid-19 can therefore “be kept low and manageable as part of an effective pandemic response that includes contact tracing and quarantine, as well as the temporary closure of schools if someone is infected“, concluded Professor Kristine Macartney, first author.”Higher transmission rates may be observed in areas where transmission of the virus is greater in the community or where public health and community response are less stringent. “, she specified.

But even in France, the figures for children are reassuring. Covid-19 in children “remain benign“, the need for hospitalization is”exceptional“, even since the circulation of the new variant, adds the French Society of Pediatrics.”Children aged 0 to 14 represent 0.3% of hospitalizations in week 11“.”Countless studies published in high-level scientific journals, in all countries and on all continents, have confirmed that children under the age of 11 not only presented much less severe forms, but were also less contaminated and much less contaminants“, already said the French Society of Pediatrics in January 2021.

Children have a stronger innate immune response than adults

If children are less affected than adolescents and adults by Covid-19, it is because they have an innate immune response, the first line of defense against infections, which is much more effective. The younger they are, the more they have high levels of certain cytokines (molecules that activate innate immunity), according to work from Yale University (United States) published in the journal Science Translational Medicine. Conversely, adults exhibited a more vigorous response of the adaptive immune system, the second highly specific line of defense of the current infection, including higher levels of antibodies. “Children appear to have a stronger and earlier innate immune response to the virus, which may protect them from progressing to severe lung disease“, concludes in a press release Pr Betsy Herold, who led this work. For this reason, very few children infected with Covid-19 require intensive care.

In Sweden, where kindergartens, primary or lower secondary, remained open, only 15 children had to be hospitalized for multi-inflammatory syndrome. This equates to 0.77 patients in intensive care per 100,000 children aged 1 to 16, concludes the study published in January 2021 in the New England Journal of Medicine. “Severe cases of Covid-19 in intensive care units are very rare in children despite the opening of schools during the pandemic“, concludes in a statement Jonas F. Ludvigsson, pediatrician and first author of the study.

An increased risk for teachers from middle school

But if children are spared, this is not the case for teachers, mainly from middle school. Also in Sweden, where middle schools were open but not high schools, researchers compared the contamination of teachers and students between classes of 3e and 2nde, whose pupils were therefore of similar ages. As a result, teachers in open colleges were twice as contaminated as those in closed high schools, reports the study published in February 2021 in the journal PNAS. On the other hand, parents of high school students had only 17% less risk of infection, compared to parents of middle school students. According to the authors, “this suggests that keeping colleges open had a minor impact on the overall spread of the virus in society“, but that teachers are on the other hand more at risk, perhaps because of transmissions between adults in schools.”Teachers affected, and measures to protect them could be considered“, conclude the authors.

In elementary and nursery school, on the other hand, the excess risk for teachers is very low. “Data from the French Ministry of National Education confirms the very low contamination of teachers (0.09 to 0.18%) and the very low number of classes or schools closed since the start of the school year in September 2020 (respectively 0.06- 0.2% and 0.14-0.04%) “, said it French Society of Pediatrics in January 2021.

Close schools, “last step to take”

Intra-school contaminations “are therefore not the main lever for blocking the transmission chain. The peak of contamination which followed the resumption of the school in January 2021 is there to attest: all the schools in France had been closed for 15 days and the number of infections has nevertheless increased very strongly.“, argues the French Society of Pediatrics.The closure of schools can only be considered if more effective measures are already in place: strict isolation and testing in the event of symptoms, true confinement, systematic teleworking, closure of non-food businesses … Closing schools is the last. action to take, when all others have failed. “

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