Epidemiological information is limited, and clinical statistics currently derive from review of case series. This emerging condition is considered rare. Its incidence is not known. Based on available reports, the fatality rate among diagnosed cases appears to have been about 1.7% (notably higher than the rate of 0.07% recorded among children with Kawasaki disease in Japan). A rapid risk assessment conducted by the European Centre for Disease Prevention and Control (ECDC) concluded that the overall risk to children in the European Union (EU), European Economic Area (EEA) and the UK "is considered 'low', based on a 'very low' probability of the disease in children and a 'high' impact of such disease." Clusters of cases of the newly described condition have been recorded 3–4 weeks after peaks in SARS-CoV-2 viral transmission through various local communities. Such observations have been seen to support the concept that SARS-CoV-2 infection may be capable of triggering a severe form of a Kawasaki-like disease. Frequent presentation without prominent respiratory symptoms in children who do not appear to have ongoing SARS-CoV-2 infection but who have already developed antibodies suggests that the disease may be driven by a delayed, post-infectious mechanism. The median age of onset appears to be at least 7 years (compared with 2 years for Kawasaki disease, which primarily affects children under the age of 5). Male children seem to be more frequently affected (broadly in line with Kawasaki disease, where the male to female ratio is about 1.5 to 1). Many affected children appear not to have underlying health conditions, such as asthma or autoimmune disorders, and there have been relatively few reports of known congenital heart disease or preexisting cardiovascular disease. Over half (52%) the children with available information had no recorded underlying health condition, including being overweight or obese (among those who did have some comorbidity, 51% were either overweight or obese). Regarding ethnicity, reports from France and the UK raised the possibility that children of Afro-Caribbean descent may be at greater risk, plausibly due to a genetic predisposition. In the US (as of mid-July), the majority of cases were classified as Hispanic/Latino (38%) or non-Hispanic Black (33%) people. Based on reports confined to Europe and the US, the condition seems to affect more children of African, Afro-Caribbean, and Hispanic descent, whereas Kawasaki disease affects more of East Asian and Pacific Islander ancestry. The role of socioeconomic and other environmental factors in such discrepancies is unclear. As regards geographical distribution, there has been uncertainty as to whether the initial reports of cases in Europe and North America reflected a true pattern, or whether the condition had gone unrecognized elsewhere. In Japan and other Southeast and East Asian countries where Kawasaki disease is usually much more prevalent than in Europe, no case of Kawasaki-like disease linked to COVID-19 had been reported during the first wave of transmission. Reports of confirmed or suspected cases have since emerged in many different countries around the world. None of the three main provisional case-definitions of the emerging entity is diagnostically specific. Concerns have been raised regarding the potential for missed or delayed diagnosis of Kawasaki disease due to heightened diagnostic suspicion for the new entity. Misclassification of cases of Kawasaki disease and of other<unk>  and infectious diseases of childhood whose case definitions overlap with MIS-C could skew understanding of the new entity, such as the frequency of coronary artery aneurysms. Another concern is that clinically less severe cases of the new entity may be missed, and that the actual spectrum of disease severity could be broader, especially given the reliance on early observations of severe disease for provisional case definition. Some statistical modeling has been used to explore possible subdivision of cases satisfying the CDC's case definition into three distinct subgroups based on underlying clinical similarities: Class 1, characterized by pronounced multiorgan involvement, with little overlap with Kawasaki disease or acute COVID-19; Class 2, more predominantly characterized by respiratory symptoms typical of acute COVID-19; Class 3, a clinically less severe grouping, where rashes and mucosal symptoms are prevalent, with less multiorgan involvement, and generally greater overlap with Kawasaki disease. A suggestion that research into the biology of the disease might benefit from considering cases of Kawasaki disease and of the provisionally defined entity in conjunction is debated. In adults There has been uncertainty as to whether the condition is confined to children, and the appropriateness of excluding adults from case definitions has been questioned. Sporadic reports exist of a similar life-threatening condition, denominated<unk><unk>  syndrome in adults' (MIS-A), which also usually requires intensive care.
Multisystem inflammatory syndrome in children
Kawasaki disease
Cutaneous manifestations of COVID-19
Systemic inflammatory response syndrome
Chest pain in children
complications of Typhus
Multiple organ dysfunction syndrome
complications of Sepsis