Multisystem Inflammatory Syndrome in Children (MIS-C) is a condition that can affect the heart, lungs, kidneys, brain, skin, eyes or stomach and intestines. The condition causes the body's immune system--which usually fights off disease-causing pathogens like bacteria and viruses--to attack the child's internal organs, resulting in symptoms like stomach pain, vomiting, diarrhea, sore muscles, rash, bloodshot eyes and/or fatigue.
While the cause of MIS-C isn't well known or well understood, 99% of children who get the syndrome previously tested positive for COVID-19; the remaining 1% were around another person who had COVID-19, according to the Centers for Disease Control and Prevention. Most children that developed the condition did so two to four weeks after they were infected with COVID-19.
RELATED: Thousands of infants, toddlers among more than 39,000 NC children who have tested positive for COVID-19
And Dr. Eve Wu, a pediatric immunologist at UNC Children's, said the syndrome can be quite acute.
"The important thing to recognize is that these children can be quite ill. Even though we think that COVID-19 infections or consequences of COVID-19 might be mild in children, we at UNC Children's have seen what it can do in its worst form and that includes children affected by this multisystem inflammatory syndrome."
Nationwide, at least 1,288 children have met the case definition for MIS-C and 23 have died after displaying symptoms of the condition. Wu added that some of the severe symptoms include sudden drops in blood pressure and an enlargement of the blood vessels around the heart.
"About 10% of children are developing aneurysms or enlargement of the coronary arteries of the heart," Wu said. "How long that lasts has not yet been determined."
WATCH: Full interview with Dr. Eve Wu
According to the North Carolina Department of Health and Human Services, at least 52 children have developed the symptoms of MIS-C in the state since May 2020, including five children in December. Wu said more than a dozen children have presented with the condition at UNC Children's, all of whom are either Latino or Black.
That's in line with national statistics--according to the CDC, 40% of cases nationwide are in Hispanic or Latino children and 38% are in Black children.
"It does seem to mirror the fact or the observation that minorities, in general, seem to be disproportionately affected by COVID-19, so it would be reasonable to expect that minority children would be disproportionately affected by MIS-C as well," Wu said.
The good news is that the disease is very rare. As of December 26, more than 57,000 children have tested positive for COVID-19 in North Carolina, meaning just 0.09% of children have developed MIS-C after a COVID-19 infection. And there are treatments available, Wu said, which can bring down a child's recovery time to anywhere from a few days to two weeks.
But, Wu added, with a recent uptick in COVID-19 cases in the general population, she expects an increase in MIS-C diagnoses in the coming months.
The CDC recommends that parents bring their children into the hospital if they notice the following symptoms, particularly after a COVID-19 infection:
- Stomach pain
- Vomiting and/or Diarrhea
- Sore muscles--particularly in the neck
- Bloodshot eyes
- Unusual fatigue
- Trouble breathing
- Continuous pain or pressure in the chest
- Confusion and inability to wake up or stay awake
- Blue lips or face
While it's not clear why some children are more predisposed to MIS-C than others, Wu said the best way to protect your child from MIS-C is to protect them from COVID-19 by washing hands often and wearing a mask whenever around someone not in the immediate household, including extended family members.