It's believed to be related to the coronavirus and there have been a handful of cases in Philadelphia.
Pediatricians are trying to unravel the mysteries of MIS-C. Kids can present with a variety of symptoms — from rashes, fevers and abdominal pain to shock. And they can become so ill that they need to be treated in the ICU.
Dr. Audrey John, chief of Children's Hospital of Philadelphia's Division of Pediatric Infectious Diseases, said they've seen between 10 and 20 cases.
"I can't be hard on the numbers because we're still trying to understand which children fit into this box," she said, "because the initial cases where all the children severely ill, they all came in in shock. So that was really easy to reocgnize, but now we're realizing there's a spectrum of illness."
John thinks the syndrome is a secondary infection that happens after the initial coronavirus infection, which didn't cause the kids to have symptoms. She also believes that some kids may be genetically susceptible to it.
"Given how widespread coronavirus infection has been, the fact that we're only talking about hundreds of cases in children, not thousands, tells me right there that it's not just the virus, it's the virus plus something else," she said.
The other good bit of news is that all the children at CHOP have recovered quickly.