“Around May 11, the epidemic will still be there” Liberation.
Following Emmanuel Macron’s announcement of the gradual reopening of schools on May 11, many of you asked us about the role of children in the spread of the epidemic. And especially those who have been contaminated and who show little or no symptoms.
Because the fact is now well established: children infected with SARS-CoV-2 develop symptoms of the disease much less frequently than adults. The low rate of positive diagnoses among the youngest could, for this reason, conceal a much higher infection rate. On this subject, works prepublished end of March – who have not yet been independently reviewed – suggest that children in contact with infected individuals are just as likely to be infected as adults under the age of 60.
However, several unknowns remain. First, it is not yet known whether infected children transmit the disease as easily as adults.
On the one hand, contaminations from child to adult are currently unnoticed in the case of asymptomatic contaminations.
On the other hand, little data exists on the infectiousness of the secretions (postillons, sputum) of children without symptoms.
More generally, the infectious potential of asymptomatic individuals, whatever their age, is not yet sufficiently documented – notably due to the difficulty of tracing these cases. At the beginning of April, WHO recalled the risk of contamination during the last days of incubation, at least three days before the onset of symptoms (“pre-symptomatic” transmission). Cases of transmission from carriers who never show symptoms can only be documented with great difficulty.
For all these reasons, the formulations used in the scientific literature devoted to this subject are still conditional (the asymptomatic character “Increases the possibility that children can be facilitators of viral transmission “, Etc.). All authors call for further investigation “On the role of children in the chain of transmission.”
Researchers working on pandemic modeling are just as circumspect. “In studies published since mid-March, including a study prepublished this April 12, we’re looking at several age classes, including a school age class. “, explains Jean-Stéphane Dhersin, researcher at the CNRS and at the Sorbonne Paris Nord University and deputy scientific director of the INSMI (National Institute of Mathematical Sciences and their Interactions). “In the models used [pour estimer les effets des mesures sanitaires], a number of parameters have to be estimated: assumptions are made that people can get the disease, that they can be infectious, and that they can spread it. However concerning children, for the moment, we do not know everything. Particularly because an active test campaign in the general population has not yet been carried out, which is the most effective way of obtaining information. In the models, data are sometimes used that are available for influenza, but it is not known if this is relevant. At this time, it is unclear whether children play an important role in the spread of the epidemic. “
Expert opinions marked by uncertainty
On this dossier, the opinions of experts remain divergent. Assuming asymptomatic children are as contagious as adults, some point out that their social interactions are based on more and more prolonged physical contact than their elders – increasing the risk of infection.
In an interview granted in March to the Swiss daily Time, Arnaud L’Huillier, pediatrician and infectious disease specialist, conversely estimated that children would transmit SARS-CoV-2 less than they would participate in the spread of the flu virus. According to him, the coronavirus in circulation “Affects especially the deep respiratory tract and does not make the nose run, which in children is an important vector for the dissemination of pathogens”.
In an exchange with the AFP, Professor Keith O’Neal, epidemiologist at the University of Nottingham, noted that asymptomatic carrier children were less risky for the community gathered in a school “That entrusted to grandparents” by adults with no other childcare solution.
At the Ministry of National Education, we are told that the risk associated with asymptomatic or pre-symptomatic transmissions in schoolyards “Is one of the points to be discussed with the social partners” to prepare for the end of containment on May 11. “It is still too early to answer these questions”.
This April 14 sure France 2, Minister Jean-Michel Blanquer stressed that going back to school “would not be mandatory ” at the end of confinement. “The goal is that between May 11 and July 4 (summer vacation date), we have successfully resocialized […] that allows you to get back into learning. “
In an exchange with the journalists of France Inter, pediatrician Robert Cohen announced on April 14 the launch of a study in Ile-de-France on 600 children, intended to assess the percentage of asymptomatic patients carrying the virus.
Listen to the weekly behind the scenes podcast from CheckNews. This week: War of masks: does the state use regional orders?
The World Health Organization (WHO) reminded him as early as January 12: “The data seem to clearly indicate that the outbreak is associated with exposures at a fish market in Wuhan” (see: Hubei). The hypothesis of a zoonosis, a disease transmitted by animals, is therefore preferred. February 7, the scientific journal Nature asks: “Has the pangolin spread the coronavirus to humans”? But nothing yet formally attests to this. Since there is nothing to certify that Sars-CoV-2, another name for Covid-19, very close to a virus detected in bats, comes from animals. The SARS coronavirus was transmitted from the civet to humans in China in 2002 and that of the Dromedary Sea to humans in Saudi Arabia in 2012.
as a balance sheet
As of Wednesday, almost two months after the virus appeared, 81,191 cases have been confirmed, including 78,064 in China. 39 countries have known or are experiencing cases. 2,728 people died, 30,310 were treated
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After being head of the infectious diseases department at the Saint-Antoine hospital in Paris, Professor Pierre-Marie Girard is now the Director of International Affairs at the Pasteur Institute in the capital and head of the International Network Instituts Pasteur, 10 of which are located in Africa.
The great fear around this new epidemic was that it would reach Africa. However, there is only one known case, in Egypt. Is this good news?
Today, no one understands why the epidemic has not yet developed on the African continent. Many experts doubt the reality of the figures displayed. The most optimistic are surprised but they bet that the epidemic will end before the African continent is hit. For pessimists, there are two possibilities: either cases have not yet been identified and it is only a matter of time, or the ever-increasing evolution of the epidemic in China, the inevitable flaws in the measures isolation and the extent of their constraints will necessarily lead to an extension of the epidemic to Africa.
Why is there such a strong doubt?
A simple observation: in Africa, there are more than a million Chinese nationals who go back and forth to their country, and there was, in addition, a strong movement around the Chinese New Year. Everything contributes to the virus circulating. Moreover, on Wednesday, there was a remarkable modeling done by an Inserm team around the Italian researcher Vittoria Colizza showing that Egypt, Algeria and South Africa would be the gateways to the most likely of the coronavirus on the African continent. To do this, they worked on the importance of air traffic with the contaminated Chinese provinces, pointing to the large air hubs through which many travelers pass. These three countries are also among the best equipped on the continent to quickly detect and deal with new cases. In other African countries, according to this research, the risk of importation is lower but the sanitary deficiencies can raise fears of a rapid diffusion.
In this case, what explains the absence or almost no case?
It is possible that there are hidden cases, infected people who did not have access to the tests or, above all, people infected during the incubation period, therefore not detectable. The most likely assumption is that the coronavirus is circulating at least quietly.
Maybe the climate is not suitable for this virus?
No. The tropical climate is not a powerful brake on the replication of coronaviruses although a partial seasonality is likely as for most respiratory viruses. To bet on climate protection in Africa or spontaneous control of the epidemic at the end of winter would be absurd.
What should be done, however, for Africa?
Prepare, and, as is the case in many African countries, with the support of international aid. With our 10 institutes, we were able to make molecular tests available as soon as they were developed. Reference centers were equipped and biologists trained from mid-January. Fortunately, infected people are mainly contagious during the first symptoms, which makes it possible to identify the people most at risk, those who can even be severely affected and transmit the virus to those around them. This allows you to act more efficiently and quickly limit the transmission.
Still, in your eyes, there will be an epidemic in Africa anyway …
In any case, nothing is finished. The epidemic is not currently under control in China, it is not known how long people will remain contagious, and as in any epidemic, there can be rebounds after phases of relative lull. It will last for months. Perhaps the worst is ahead of us. But if the worst is never certain, it would be collectively unacceptable not to prepare for it and thus ignore the risks run by the poorest countries.