SARS-CoV-2 Variants and Multisystem Inflammatory Syndrome in Children

This international study assessed 2017 children hospitalized with SARS-CoV-2 infection and diagnosed with multisystem inflammatory syndrome in children (MIS-C) from April 2020 to June 2022, using data from the International Kawasaki Disease Registry. Patients were grouped by dominant variant periods ancestral, alpha+, delta, and omicron to compare demographics, clinical phenotypes, and outcomes. The severity of MIS-C progressively declined with successive variants. Delta and omicron periods saw fewer cases of respiratory dysfunction and coronary-artery dilatation, and more resemblance to Kawasaki’s disease. Use of intravenous glucocorticoids increased over time, and risks of serious complications, ICU admission, and mortality decreased,most markedly during the omicron period. However, severe disease including shock and ventricular dysfunction persisted, especially during alpha+. The study underscores evolving clinical patterns and improved outcomes but notes ongoing prevalence of critical illness.

This international study assessed 2017 children hospitalized with SARS-CoV-2 infection and diagnosed with multisystem inflammatory syndrome in children (MIS-C) from April 2020 to June 2022, using data from the International Kawasaki Disease Registry. Patients were grouped by dominant variant periods ancestral, alpha+, delta, and omicron to compare demographics, clinical phenotypes, and outcomes. The severity of MIS-C progressively declined with successive variants. Delta and omicron periods saw fewer cases of respiratory dysfunction and coronary-artery dilatation, and more resemblance to Kawasaki’s disease. Use of intravenous glucocorticoids increased over time, and risks of serious complications, ICU admission, and mortality decreased,most markedly during the omicron period. However, severe disease including shock and ventricular dysfunction persisted, especially during alpha+. The study underscores evolving clinical patterns and improved outcomes but notes ongoing prevalence of critical illness.