Table 1.

Abbreviate case definitions from the UK Royal College of Paediatrics and Child Health (RCPCH) for PIMS-TS, the US Centre for Disease Control and Prevention (CDC) for MIS-C, and the World Health Organization (WHO) for multisystem inflammatory syndrome in children and adolescents temporally related to COVID-19

Paediatric Inflammatory Multisystem Syndrome Temporally associated with SARS-CoV-2 (PIMS-TS; RCPCH 2020)	Multisystem Inflammatory Syndrome in Children (MIS-C; CDC 2020)	Multisystem inflammatory syndrome in children and adolescents temporally related to COVID-19 (WHO 2020)
A child presenting with persistent fever, inflammation and evidence of single or multi-organ dysfunction	An individual aged < 21 years presenting with fever, inflammation, and severe illness requiring hospitalization, with multisystem (> 2) organ involvement	Children and adolescents 0–19 years of age with fever > 3 days
This may include children meeting full or partial criteria for Kawasaki disease	No alternative plausible diagnoses	AND two of the following:  - Rash or bilateral non-purulent conjunctivitis or muco-cutaneous inflammation signs  . Hypotension or shock  . Features of myocardial dysfunction, pericarditis, valvulitis, or coronary abnormalities  . Evidence of coagulopathy  . Acute gastrointestinal problems
Exclusion of any other microbial cause	Positive for current or recent SARS-CoV-2 infection by RT-PCR, serology, or antigen test; or COVID-19 exposure within the 4 weeks prior to the onset of symptoms	AND Elevated markers of inflammation
SARS-CoV-2 PCR testing may be positive or negative	Some individuals may fulfil full or partial criteria for Kawasaki disease but should be reported if they meet the case definition for MIS-C	AND No other obvious microbial cause of inflammation
	Consider MIS-C in any paediatric death with evidence of SARS-CoV-2 infection	AND Evidence of COVID-19, or likely contact with patients with COVID-19