Multisystem Inflammatory Syndrome in Children: Characteristics and Epidemiology

ABSTRACT

Shortly after the novel coronavirus (now known as SARSCoV- 2) was recognized, data began to accumulate on the virus's effects on children. Initial data showed that children were more likely to be mildly affected, compared to adults, with lower risks of hospitalization and death. However, in April of 2020, reports appeared of a severe disease in children occurring about two-six weeks after infection with SARS-CoV-2. The features were similar to those seen in a rare vasculitis condition called Kawasaki disease. On May 14, 2020, the Centers for Disease Control and Prevention (CDC) issued a national health advisory regarding this new condition, which was called multisystem inflammatory syndrome in children (MIS-C). The current case definition for MIS-C includes six criteria (1) serious illness leading to hospitalization or resulting in death;(2) age less than 21 years;(3) measured fever over 38 degrees Celsius or report of subjective fever;(4) laboratory evidence of inflammation;(5) new onset involvement in at least two of the following (cardiac involvement, mucocutaneous involvement, shock, gastrointestinal involvement, and hematologic involvement);and (6) laboratory-confirmed SARS-CoV-2 infection or an epidemiologic link to a person with COVID-19. According to CDC, as of January 3, 2023, there have been 9,333 patients in the United States meeting the case definition of MIS-C, with 76 deaths. The median age of patients was nine years, with half of those affected between the ages of five and 13 years. More than half of the reported patients on whom race-ethnicity information was available were in children who are Hispanic/Latino or Black, non-Hispanic. Over 60% of reported patients were male. Most affected children had previously been healthy. A better understanding of the pathogenesis of this serious illness is needed to provide better treatment options for children with MIS-C. Prevention of MIS-C is focused on the prevention of SARS-CoV-2 infection through staying up to date with COVID-19 vaccination, masking, and other prevention strategies.