Table 1. CSTE/CDC definition of confirmed MIS-C case [4,13]

A patient aged < 21 years with fever (≥ 38.0°C) and clinical severity requring hospitalization
1. Systemic inflammation: CRP ≥ 3.0 mg/dL
2. Organ involvement ≥ 2/5 categories
i) Cardiac: EF < 55%, CAAs, or Tn elevation ii) Mucocutaneous: skin rash, conjunctivitis, oropharyngeal inflammation, or extremity changes iii) Shock: clinician documentation in medical records iv) Gastrointestinal: abdominal pain, vomiting, or diarrhea v) Hematologic: platelet count < 150,000 /μL or ALC < 1,000 /μL
3. Laboratory evidence of SARS-CoV-2 infection detection of SARS-CoV-2 RNA (i.e., PCR) or SARS-CoV-2-specific antigen or antibodies up to 60 days before or during hospitalization

CSTE/CDC: The Council of State and Territorial Epidemiologists/Centers for Disease Control and Disease Prevention; MIS-C: multisystem inflammatory syndrome in children; CRP: C-reactive protein; EF: ejection fraction; CAAs: coronary artery abnormalities; Tn: troponin; ALC: absolute lymphocyte count; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.