Trends in Geographic and Temporal Distribution of US Children with Multisystem Inflammatory Syndrome During the COVID-19 Pandemic

Multiple inflammatory syndrome in children (MIS-C) occurs in association with the COVID-19 pandemic.


To describe the clinical characteristics and geographic and temporal distribution of the largest cohort of patients with MIS-C in the United States to date.

Design, Setting, and Participants

Cross-sectional analysis was conducted on clinical and laboratory data collected from patients with MIS-C. The analysis included patients with illness onset from March 2020 to January 2021 and met MIS-C case definition.

Main Outcomes and Measures

Geographic and temporal distribution of MIS-C was compared with that of COVID-19 nationally, by region, and level of urbanicity by county. Clinical and laboratory findings and changes over time were described by age group and by presence or absence of preceding COVID-19.


A total of 1733 patients with MIS-C were identified; 994 (57.6%) were male and 1117 (71.3%) were Hispanic or non-Hispanic Black. Gastrointestinal symptoms, rash, and conjunctival hyperemia were reported by 53% (n = 931) to 67% (n = 1153) of patients. A total of 937 patients (54%) had hypotension or shock, and 1009 (58.2%) were admitted for intensive care. Cardiac dysfunction was reported in 484 patients (31.0%), pericardial effusion in 365 (23.4%), myocarditis in 300 (17.3%), and coronary artery dilatation or aneurysms in 258 (16.5%). Patients aged 0 to 4 years had the lowest proportion of severe manifestations, although 171 patients (38.4%) had hypotension or shock and 197 (44.3%) were admitted for intensive care. Patients aged 18 to 20 years had the highest proportions with myocarditis (17 [30.9%]), pneumonia (20 [36.4%]), acute respiratory distress syndrome (10 [18.2%]), and polymerase chain reaction positivity (39 [70.9%]). These older adolescents also had the highest proportion reporting preceding COVID-19–like illness (63%). Nationally, the first 2 MIS-C peaks followed the COVID-19 peaks by 2 to 5 weeks. The cumulative MIS-C incidence per 100 000 persons younger than 21 years was 2.1 and varied from 0.2 to 6.3 by state. Twenty-four patients (1.4%) died.

Conclusions and Relevance

In this cross-sectional study of a large cohort of patients with MIS-C, 2 peaks that followed COVID-19 peaks by 2 to 5 weeks were identified. The geographic and temporal association of MIS-C with the COVID-19 pandemic suggested that MIS-C resulted from delayed immunologic responses to SARS-CoV-2 infection. The clinical manifestations varied by age and by presence or absence of preceding COVID-19.

Masters of Pediatrics™ (MoP) is dedicated to the advancement of healthcare technologies and education serving as the academic home for child health professionals. Masters of Pediatrics offers continuing medical education, activities, and training through its advanced education entity Metabolic Medical Institute (MMI).
A division of Tarsus Medical owned by Tarsus Group

+1 (888) 555-1212

Copyright © 2021, A4M. All trademarks, registered or unregistered, are the property of their respective owners.