Multisystem Inflammatory Syndrome in US Children

Quick Takes

  • Multisystem inflammatory syndrome in children (MIS-C) is associated with a significant need for critical care, with a high rate of cardiac involvement, and an overall mortality rate of 2%.
  • MIS-C differs from Kawasaki disease in that there is a higher rate of cardiovascular shock prompting need for inotropic/vasopressor support (50%) and a lower rate of coronary artery involvement (8%).
  • Further study is required to understand the long-term cardiac sequelae of MIS-C, including coronary involvement.

Study Questions:

What is the epidemiology and clinical course of multisystem inflammatory syndrome in children (MIS-C) and its temporal association with coronavirus disease 2019 (COVID-19)?


A multicenter review was performed at 53 centers between March 15 and May 20, 2020. The case definition required: serious illness leading to hospitalization, an age of <21 years, fever for >24 hours, laboratory evidence of inflammation, multisystem organ involvement, and evidence of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Evidence of SARS-CoV-2 infection included positive reverse-transcriptase polymerase chain reaction (RT-PCR), antibody testing, or exposure to patients with COVID-19 in the past month.


A total of 186 patients with MIS-C were identified in 26 states. The median age was 8.3 years and 62% were male. Most patients (70%) were positive for SARS-CoV-2 based on RT-PCR or antibody testing, with the remainder having exposure to patients with COVID-19. Gastrointestinal organ system involvement was most common (92%), followed by cardiovascular (80%), hematologic (76%), mucocutaneous (74%), and respiratory (70%). The median duration of hospitalization was 7 days, while 80% of patients required intensive care, 20% received mechanical ventilation, 48% received vasoactive support, and 2% died. Coronary artery aneurysms (z-scores ≥2.5) were seen in 8% of patients. Intravenous immune globulin was used in 77% of patients, glucocorticoids in 49%, and interleukin-6 or 1RA inhibitors in 20%.


MIS-C in children associated with SARS-CoV-2 led to serious and life-threatening illness in previously healthy children and adolescents.


This is one of two studies published in the New England Journal of Medicine online on June 29, 2020, describing targeted surveillance for MIS-C. Previous smaller studies have described a disease with critical illness, but a relatively high rate of myocardial recovery with treatment with immunomodulating therapies such as intravenous immune globulin. Although MIS-C has some common features with Kawasaki disease, it appears to be a distinct clinical entity with a different spectrum of cardiac involvement. Further study will be required to better understand the link between MIS-C and COVID-19, as well as the long-term cardiac effects of the disease process.

Clinical Topics: Congenital Heart Disease and Pediatric Cardiology, Prevention, Stable Ischemic Heart Disease, Vascular Medicine, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Prevention, Chronic Angina

Keywords: Adolescent, Child, Coronary Aneurysm, Coronary Vessels, Coronavirus, COVID-19, Critical Illness, Glucocorticoids, Immunoglobulins, Intravenous, Inflammation, Interleukin-6, Pediatrics, Primary Prevention, Respiration, Artificial, Reverse Transcriptase Polymerase Chain Reaction, SARS Virus, severe acute respiratory syndrome coronavirus 2

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