AUTHOR=Kechiche Robin , Borocco Charlotte , Bajolle Fanny , Belot Alexandre , Poignant Sylvaine , Lachaume Noémie , Percheron Lucas , Meinzer Ulrich , Mertes Clara , Despert Véronique , Morin Luc , Lambert Virginie , Dusser Perrine , Matsa Nassima , Hentgen Véronique , Kone-Paut Isabelle , Galeotti Caroline 

TITLE=Multisystem inflammatory syndrome in children during the COVID-19 waves: data from the Juvenile Inflammatory Rheumatism cohort

JOURNAL=Frontiers in Pediatrics

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2023.1126985

DOI=10.3389/fped.2023.1126985

ISSN=2296-2360

ABSTRACT=<sec><title>Introduction</title><p>Multisystem inflammatory syndrome in children (MIS-C) is a new condition that first appeared in children and adolescents during the COVID-19 pandemic. We aimed to describe the diagnostic course, clinical and biological manifestations, and treatment of MIS-C during the first three COVID-19 waves.</p></sec><sec><title>Methods</title><p>We extracted patient data from the Juvenile Inflammatory Rheumatism (JIR) cohort. We analyzed data for patients meeting the World Health Organization diagnostic criteria for MIS-C from the start of the COVID-19 pandemic from March 2020 to June 30, 2021. We then compared data for patients in wave one to those in waves two and three.</p></sec><sec><title>Results</title><p>We identified 136 patients with MIS-C. The median age decreased but not significantly during the waves, from 9.9 years to 7.3 years (<italic>p</italic> = 0.105). Boys represented 52.2% (<italic>n</italic> = 71) of patients, and 46% (<italic>n</italic> = 41) of patients originated from sub-Saharan Africa (<italic>p</italic> &lt; 0.001). Patients presented less diarrhea (<italic>p</italic> = 0.004), respiratory distress (<italic>p</italic> &lt; 0.001), and myocarditis (<italic>p</italic> &lt; 0.001) with progressive waves. Biological inflammation also decreased, namely, C-reactive protein level (<italic>p</italic> &lt; 0.001), neutrophil count (<italic>p</italic> = 0.004), and albumin level (<italic>p</italic> &lt; 0.001). Patients received more corticosteroids (<italic>p</italic> &lt; 0.001) and required less ventilation support (<italic>p</italic> &lt; 0.01) and less inotrope treatment (<italic>p</italic> &lt; 0.001) in the later waves. The duration of hospitalization gradually decreased (<italic>p</italic> &lt; 0.001), as did critical care unit admissions (<italic>p</italic> = 0.002).</p></sec><sec><title>Conclusion</title><p>Over the three COVID-19 waves, with a change in the management of MIS-C, children in the JIR cohort in France showed a less severe disease course, in particular, a greater use of corticosteroids. This observation may reflect the impact of both improved management and different SARS-CoV-2 variant.</p></sec>