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Multisystem Inflammatory Syndrome in Children-United States, February 2020-July 2021
Allison D Miller1, Laura D Zambrano1, Anna R Yousaf1
1CDC COVID-19 Response Team, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Insights
Multisystem inflammatory syndrome in children (MIS-C) cases showed decreasing cardiovascular complications and improved outcomes over three pandemic waves. This trend offers a baseline for monitoring future MIS-C developments in children.
Area of Science:
- Pediatric Infectious Diseases
- Epidemiology
- Public Health
Background:
- Multisystem inflammatory syndrome in children (MIS-C) is a severe hyperinflammatory condition linked to SARS-CoV-2 infection in individuals under 21.
- The CDC has been collecting national surveillance data on MIS-C cases since the COVID-19 pandemic began.
Purpose of the Study:
- To describe MIS-C cases reported to the CDC's national surveillance system.
- To analyze trends in MIS-C demographics, clinical presentation, and outcomes across three pandemic waves.
Main Methods:
- Analysis of 4470 MIS-C cases meeting the case definition with onset dates from February 2020 to July 2021.
- Utilized CDC's MIS-C case report form for data collection on demographics, clinical features, and laboratory results.
- Assessed trends over time using statistical tests (Cochran-Armitage and Jonckheere-Terpstra) across three pandemic waves.
Main Results:
- Median patient age increased to 9 years in the third wave, with a rise in male predominance (62%).
- Significant increases in hematologic and gastrointestinal involvement were observed.
- Decreases in cardiovascular complications (e.g., myocarditis, shock), renal failure, critical care needs (mechanical ventilation, ECMO), hospitalization duration, and mortality were noted.
Conclusions:
- Over the first three pandemic waves, MIS-C cases in the US demonstrated declining cardiovascular complications and improved clinical outcomes.
- These findings establish a crucial baseline for tracking future MIS-C trends related to SARS-CoV-2 variants like Delta and pediatric COVID-19 vaccination.
Background:
Multisystem inflammatory syndrome in children (MIS-C) is a severe hyperinflammatory condition in persons aged <21 years associated with antecedent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our objective was to describe MIS-C cases reported to Centers for Disease Control and Prevention's (CDC's) national surveillance since the coronavirus disease 2019 (COVID-19) pandemic began.
Methods:
We included patients meeting the MIS-C case definition with onset date from 19 February 2020 through 31 July 2021, using CDC's MIS-C case report form, which collects information on demographics, clinical presentation, and laboratory results. Trends over time across 3 MIS-C pandemic waves were assessed using Cochran-Armitage test for categorical and Jonckheere-Terpstra test for continuous variables.
Results:
Of 4901 reported cases, 4470 met inclusion criteria. Median patient age increased over time (P < .001), with a median of 9 years (interquartile range, 5-13 years) during the most recent (third) wave. Male predominance also increased (62% in third wave, P < .001). A significant (P < .001) increase in severe hematologic and gastrointestinal involvement was observed across the study period. Frequency of several cardiovascular complications (ie, cardiac dysfunction, myocarditis, and shock/vasopressor receipt) and renal failure declined (P < .001). Provision of critical care including mechanical ventilation (P < .001) and extracorporeal membrane oxygenation (ECMO; P = .046) decreased, as did duration of hospitalization and mortality (each P < .001).
Conclusions:
Over the first 3 pandemic waves of MIS-C in the United States, cardiovascular complications and clinical outcomes including length of hospitalization, receipt of ECMO, and death decreased over time. These data serve as a baseline for monitoring future trends associated with SARS-CoV-2 B.1.617.2 (Delta) or other variants and increased COVID-19 vaccination among children.
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