The two studies, published in the New England Journal of Medicine, are based on nearly 300 children and young people under 21 who had Covid-19 (or strong suspicions), identified in the United States between March and May, at following an alert launched in the United Kingdom at the end of April and then by the American centers for disease prevention and control (CDC) in May.
A thousand cases have been reported worldwide including these new studies, according to Michael Levin of Imperial College London in an editorial published by NEJM. On May 15, the European Center for Disease Prevention and Control reported 230 cases in Europe, including two deaths in France and the United Kingdom.
The syndrome then appears, several weeks after infection with the SARS-CoV-2 virus: a national study suggests 25 days of median duration, while the other, in New York, indicates that the majority of cases are presented a month after the peak of the pandemic in the city.
The disease is confirmed as very rare: two cases per 100,000 people under the age of 21. As already observed by doctors on both sides of the Atlantic, black, Hispanic or Indian children are relatively more affected than white children.
The most common symptom is not respiratory: more than 80% of children actually suffered from gastrointestinal complaints (abdominal pain, nausea or vomiting, diarrhea), and many had rashes, especially those under the age of five. All had fever, very often for more than four or five days. And in 80% of them, the cardiovascular system was concerned. From 8 to 9% of children have developed an aneurysm of the coronary arteries.
80% in intensive care
Most of the children were previously healthy and had no risk factors or pre-existing illnesses. 80% were admitted to intensive care, 20% received invasive respiratory assistance and 2% died.
The mystery remains about the cause of the syndrome, which is believed to be linked to an abnormal immune system response. Clarifying it could have implications for vaccine development and the inflammation also seen in multiple organs in adults with Covid-19, suggests Michael Levin.
ats / jfe