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

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

doi:10.3389/fped.2023.1126985

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

Front Pediatr. 2023 May 24:11:1126985. doi: 10.3389/fped.2023.1126985. eCollection 2023.

Authors

Robin Kechiche¹, Charlotte Borocco¹, Fanny Bajolle², Alexandre Belot³, Sylvaine Poignant⁴, Noémie Lachaume⁵, Lucas Percheron⁶, Ulrich Meinzer⁷, Clara Mertes⁸, Véronique Despert⁹, Luc Morin¹⁰, Virginie Lambert^{11

12}, Perrine Dusser¹, Nassima Matsa¹, Véronique Hentgen¹³, Isabelle Kone-Paut¹, Caroline Galeotti¹

Affiliations

¹ Department of Pediatric Rheumatology, Reference Centre for Autoinflammatory Diseases and Amyloidosis (CEREMAIA), Bicêtre University Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris-Saclay University, Le Kremlin-Bicêtre, France.
² Department of Pediatric Cardiology, M3C-Necker, Necker-Enfants Malades Hospital, AP-HP, Paris Cité University, Paris, France.
³ Department of Pediatric Nephrology, Rheumatology, Dermatology, Reference Centre of Inflammatory Rheumatism and Rare Autoimmune Diseases in Children (RAISE), Hôpital Femme-Mère-Enfant, Hospices Civils de Lyon, Bron, France.
⁴ Department of Pediatrics, Nantes University Hospital, Nantes, France.
⁵ Department of Pediatrics, Louis Mourier University Hospital, AP-HP, Paris-Cité University, Colombe, France.
⁶ Pediatrics-Nephrology, Internal Medicine and Hypertension, Children Hospital-Toulouse University Hospital, Toulouse, France.
⁷ Department of General Pediatrics, Pediatric Rheumatology and Infectious Diseases, National Reference Centre for Rare Pediatric Inflammatory Rheumatisms and Systemic Autoimmune Diseases (RAISE), Robert Debré University Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
⁸ Department of Pediatrics, Strasbourg University Hospital, Strasbourg, France.
⁹ Department of Pediatrics, Rennes University Hospital, Rennes, France.
¹⁰ Pediatric Intensive Care Unit, Bicêtre University Hospital, AP-HP, Paris-Saclay University, Le Kremlin-Bicêtre, France.
¹¹ Department of Pediatric Radiology, Bicêtre University Hospital, AP-HP, Paris-Saclay University, Le Kremlin-Bicêtre, France.
¹² Pediatric Cardiology, Institut Mutualiste Montsouris, Paris, France.
¹³ Department of Pediatrics, Reference Centre for Autoinflammatory Diseases and Amyloidosis (CEREMAIA), Versailles Hospital, Versailles, France.

Abstract

Introduction: 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.

Methods: 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.

Results: 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 (p = 0.105). Boys represented 52.2% (n = 71) of patients, and 46% (n = 41) of patients originated from sub-Saharan Africa (p < 0.001). Patients presented less diarrhea (p = 0.004), respiratory distress (p < 0.001), and myocarditis (p < 0.001) with progressive waves. Biological inflammation also decreased, namely, C-reactive protein level (p < 0.001), neutrophil count (p = 0.004), and albumin level (p < 0.001). Patients received more corticosteroids (p < 0.001) and required less ventilation support (p < 0.01) and less inotrope treatment (p < 0.001) in the later waves. The duration of hospitalization gradually decreased (p < 0.001), as did critical care unit admissions (p = 0.002).

Conclusion: 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.

Keywords: COVID-19; epidemiology; multisystem inflammatory syndrome in children; myocarditis; waves of COVID-19.