coronary artery aneurysms; covid-19; Kawasaki disease; Multisystem Inflammatory Syndrome In Children; cardiovascular disease; child; clinical feature; cohort analysis; complication; conference abstract; controlled study; coronary artery aneurysm; coronavirus disease 2019; drug therapy; female; human; intravenous drug administration; major clinical study; male; mucocutaneous lymph node syndrome; Netherlands; nonhuman; pandemic; pediatric multisystem inflammatory syndrome; preschool child; rank sum test; risk factor; Severe acute respiratory syndrome coronavirus 2; human immunoglobulin; unclassified drug