Professor Alexandre Belot is a pediatrician at the Mother-Child-Child Hospital in Lyon (Rhône). He saw several small patients with a particular form of Kawasaki syndrome. Researcher in a reference center in infectious diseases, he also led an epidemiological study to identify all cases, with Public Health France. We learn that since the beginning of the epidemic, 125 children and adolescents (with an average age of eight years) have developed this rare inflammatory disease in France. Among them, a nine-year-old boy died in Marseilles. For the doctor, the correlation between Kawasaki and coronavirus is no longer in doubt today. Childhood pathology has also been observed in many countries severely affected by the new coronavirus, such as the United States, Italy and Spain.
Is the link between Kawasaki syndrome and Sars-Cov-2 definitively established?
ALEXANDRE BELOT. Yes, it is confirmed. We already had microbiological data but the monitoring and epidemiology study that we conducted allowed us to show, in time and in space, that the link between the virus and the hyper-inflammatory syndrome of Kawasaki is a real phenomenon. We noted a notable increase in the number of cases four weeks after the epidemic wave that crossed the country, then a significant decrease. They were concentrated in the regions where the virus was strongly present: Grand-Est (9.6% of cases), Ile-de-France (58.4%) and, to a lesser extent, Auvergne- Rhône-Alpes. Most patients carried the virus, as demonstrated by PCR or serological tests. The English also speak now of post-Covid inflammatory syndrome.
What are the symptoms ?
A high fever, a deterioration in the general condition of the child, a rash that resembles that of scarlet fever, red eyes, dry lips, lymph nodes ... More than half of the patients had atypical forms with myocarditis, an inflammation of the heart muscle. This heart attack is more frequent here than for the usual Kawasaki diseases.
Did children have a specific risk factor?
No, the majority did not suffer from chronic diseases and had no identified risk factors such as obesity or hypertension. The risk is therefore not greater in children deemed to be more fragile.
It seems that many are of African origin ...
These elements come to us from the English: they report more cases in the African and Caribbean populations. For our part, we have not provided this data but we will do so. In France, ethnic statistics are prohibited, but there may be exceptions when an illness seems more severe for a particular population. We will ask the Cnil (Editor's note: National Commission for Information Technology and Liberties) for permission to look at this parameter to better understand the pathology.
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In Le Parisien, Minister Olivier Véran said two weeks ago that he had asked for an analysis to find out if Kawasaki could be a mutated form of the virus. What do you think ?
We do not yet have this data, but it is one of the two major fields that we are exploring. There are two hypotheses: either the development of the disease is favored by an excess of the immune response of certain children, on the background of genetic factors. Either it is linked to mutations in the virus itself which would cause this type of response in young patients. This is one of the important things to clear up.
We thought this rare syndrome. Does the death of the nine-year-old boy in Marseille reshuffle the cards?
This tragic death calls for ever more surveillance and vigilance. Of course, Kawasaki disease is severe and this form associated with Sars-Cov-2 is all the more particular as it increases the risk of myocarditis. But it should also be noted that it responds well - and quickly - to usual treatments, by infusion of drugs. The earlier her treatment, the better she is treated, even if the supervision required in intensive care can legitimately impress.
Does this syndrome question the return to school?
No, all learned societies of paediatrics have called for a return to school. I stand behind this public health message. Let's put things in perspective: the situation is extremely rare. There are a few dozen cases of Kawasaki, against millions of people who have been exposed to the virus. For hundreds of thousands of children, there has been no manifestation of the disease. The majority of them are asymptomatic and - as we now know - very few vectors of Covid-19. There is a magnifying effect on the coronavirus but you should know that between January and March, ten children died from the flu. The recommendations for return to school remain the same. And, since there is no particular risk factor, it must concern all children.