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Michael Levin, F.Med.Sci., Ph.D.
June 29, 2020
DOI: 10.1056/NEJMe2023158
The recognition and description of new diseases often resemble the parable of the blind men and the elephant, with each declaring that the part of the beast they have touched fully defines it. As the coronavirus disease 2019 (Covid-19) pandemic has evolved, case reports have appeared describing children with unusual febrile illnesses that have features of Kawasaki’s disease,1 toxic shock syndrome,2 acute abdominal conditions, and encephalopathy, along with other reports of children with fever, elevated inflammatory markers, and multisystem involvement.3-5 It is now apparent that these reports were describing different clinical presentations of a new childhood inflammatory disorder.
The published reports have used a variety of hastily developed case definitions based on the most severe cases, possibly missing less serious cases. The CDC and WHO definitions require evidence of SARS-CoV-2 infection or exposure — a requirement that is problematic, since asymptomatic infections are common and antibody testing is neither universally available nor reliable.
Overall, a consistent clinical picture is emerging. MIS-C occurs 2 to 4 weeks after infection with SARS-CoV-2. The disorder is uncommon (2 in 100,000 persons <21 years of age) as compared with SARS-CoV-2 infection diagnosed in persons younger than 21 years of age over the same period (322 in 100,000).7Most patients with MIS-C have antibodies against SARS-CoV-2, and virus is detected in a smaller proportion. A relatively high proportion of cases have occurred among black, Hispanic, or South Asian persons.5-8
June 29, 2020
DOI: 10.1056/NEJMe2023158
The recognition and description of new diseases often resemble the parable of the blind men and the elephant, with each declaring that the part of the beast they have touched fully defines it. As the coronavirus disease 2019 (Covid-19) pandemic has evolved, case reports have appeared describing children with unusual febrile illnesses that have features of Kawasaki’s disease,1 toxic shock syndrome,2 acute abdominal conditions, and encephalopathy, along with other reports of children with fever, elevated inflammatory markers, and multisystem involvement.3-5 It is now apparent that these reports were describing different clinical presentations of a new childhood inflammatory disorder.
The published reports have used a variety of hastily developed case definitions based on the most severe cases, possibly missing less serious cases. The CDC and WHO definitions require evidence of SARS-CoV-2 infection or exposure — a requirement that is problematic, since asymptomatic infections are common and antibody testing is neither universally available nor reliable.
Overall, a consistent clinical picture is emerging. MIS-C occurs 2 to 4 weeks after infection with SARS-CoV-2. The disorder is uncommon (2 in 100,000 persons <21 years of age) as compared with SARS-CoV-2 infection diagnosed in persons younger than 21 years of age over the same period (322 in 100,000).7Most patients with MIS-C have antibodies against SARS-CoV-2, and virus is detected in a smaller proportion. A relatively high proportion of cases have occurred among black, Hispanic, or South Asian persons.5-8
