Covid-19: Risk of PIMS, a serious form in children, has disappeared since Omicron arrived.

With the prevalence of contamination due to the Omicron variant, pediatricians share a great fear: that these extremely severe forms of pediatric multisystem inflammatory syndrome (PIMS) among children and adolescents will increase in the same proportion. With a six-month retreat, there is something to be reassured about.

According to the latest report published by Public Health France on Thursday evening, 1,048 cases of PIMS associated with SARS-CoV-2 have been identified since the onset of the epidemic. About 70% of infected minors are between the ages of 0 and 10 years. 713 of them needed serious care, and one small child died. During the first Omicron wave, in January 2022, the number of identified pims per week increased to about 30. It peaked in the spring and then in the fall of 2020. Apart from that the number of children tested positive and especially hospitalized with covid diagnosis was about 10 times higher at this time.

Suddenly, “proportionately, there are far fewer pims than before, and we can see it on the ground,” confirmed the president of the French Pediatric Society, Pro Crystal Grass Le Nguyen. Last March and April, when the epidemic soared with the Omicron BA.2 variant, “a low plateau was observed in two to four cases per week,” Public Health France points out.

Low risk has been confirmed by many studies

The same observation appears in the United States. In the middle of the Delta alternate wave in January 2021, the daily number of PIMS increased to 35, and a year later to 20 with Omicron. However, the explosion of pollution led to three times more positive cases last January.

So, will Omicron lead to less pediatric multisystem inflammatory syndrome in children? Yes, according to several recent studies. According to one of them, conducted in Denmark and published in the scientific journal JAMA Pediatrics on June 8, the risk of PIMS among immunized children appears to be “significantly lower”, exactly 8 times lower, than in the Omicron majority era. Delta variant. In France, 95% of children between the ages of 5 and 11 did not receive a dose of the vaccine.

The author states that this “may be explained by the low potency of omikron to trigger hyperinflammation, as it is phylogenetically isolated and associated with increased immunity.” This variant actually has many mutations compared to the previous SARS-CoV-2 strain, which allows people already infected with covid to re-infect.

In Israel, the incidence of PIMS in the alpha or delta variant era was about 13 times higher than in the period after Omicron became the majority, according to other research in the Journal of the American Medical Association on May 19. “Possible explanations include the Omicron variant itself, previous SARS-CoV-2 infections, vaccinations, and improved treatment over time,” the authors say.

New waves with Omicron BA.5

“Omicron is probably less viral internally, but the question is whether it can be explained by the fact that PIMS mainly occurs after the initial infection,” Crystal Grass Le Gwen rebounded. The risk of a very severe form of Covid-19 may be lower if the child is already infected, thanks to his or her immunity. By the same token, several studies have shown that vaccination makes it possible to limit the risk of PIMS.

“The lower risk (with the Omicron variant) may also be partially explained by a reduced risk after re-infection, although only 6% of individuals were re-infected through confirmation”, the authors of the published study indicate. Clothing in pediatrics.

If fewer pims have been seen in recent weeks, babies are not completely safe from covid. The number of juveniles hospitalized for the treatment of covid and the number of critical care began to rise again in March and April, even before re-reading during the spring. Furthermore, we cannot yet confirm that the situation will not change with the new BA.4 and especially the sub-lineage of the BA.5 Omicron variant, now the majority and the origin of a new epidemic wave this summer.

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