Hilmes, Melissa A.

OBJECTIVES We aimed to characterize the frequency of major complications of acute COVID-19 and multisystem inflammatory syndrome in children (MIS-C) and adolescents present at 6 months after initial presentation. METHODS The Pediatric Research Immune Network on SARS-CoV-2 and MIS-C (PRISM) study was a prospective cohort at 20 US pediatric academic medical centers. Individuals aged younger than 21 years meeting any of the following were enrolled: SARS-CoV-2 detection within 7 days, Centers for Disease Control and Prevention (CDC) MIS-C criteria, or CDC MIS-C criteria except having involvement of 1 organ system. The study was designed to assess the proportion of children with major complications (cardiovascular, pulmonary, gastrointestinal/hepatic, renal, and/or neurologic) 6 months after presentation. RESULTS Data were analyzed on 229 hospitalized participants: 59 with COVID-19 (mean age 10.4 years; SD, 5.5) and 170 with MIS-C (mean age 10.1 years; SD, 4.8). Overall, 42.8% were female, making up 55.9% and 38.2% of the COVID-19 and MIS-C groups, respectively. Overall, the frequencies of major complications at 6 months after initial presentation were: 16/195 (8.2%) cardiovascular, 11/154 (7.1%) pulmonary, 11/154 (7.1%) gastrointestinal/hepatic, 3/152 (2.0%) renal, and 3/189 (1.6%) neurologic. Organ system complications did not differ significantly between the COVID-19 and MIS-C groups. Six of 14 (42.9%) COVID-19 and 21/26 (80.7%) MIS-C participants with at least 1 six-month complication had no underlying medical condition that may have been associated with their complication(s). CONCLUSIONS Major complications were infrequent but observed in children without underlying medical conditions, underscoring the importance of prospective follow-up to optimize management and elucidate the complications associated with severe SARS-CoV-2 infection in children.