MIS-C causes body parts to become inflamed; including the heart, lungs, kidneys, brain, skin, eyes and/or gastrointestinal (digestive) organs. Most children with this syndrome had COVID-19 or were around someone with COVID-19 a few weeks before developing MIS-C symptoms.

Children often have few or mild symptoms of COVID-19, making it challenging to know they were infected with the virus. MIS-C develops a few weeks later, and for most children is the first time they appear ill. MIS-C can be serious, even deadly, but most children diagnosed get better with medical care.