Two studies today describe new findings in the COVID-19–associated multisystem inflammatory syndrome in children (MIS-C) and the distinct but similar Kawasaki disease (KD).Low blood pressure, shock, heart dysfunctionIn the first study, published in JAMA Pediatrics, a team led by researchers from the US Centers for Disease Control and Prevention (CDC) used lab data to compare geographic and temporal distribution of MIS-C from March 2020 to January 2021 with that of COVID-19 over the same period.In the largest known cohort of MIS-C patients and their distributions across the United States, the cumulative incidence was 2.1 per 100,000 people 21 and younger and varied by state, from 0.2 to 6.3 per 100,000.