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Pediatric multi-system inflammatory syndrome: What we know so far

For several months, it seemed like kids were virtually unaffected by COVID-19. Most reports seemed to indicate that children might get a runny nose and a fever if they were infected with novel coronavirus, but would probably recover with little assistance. Unfortunately, some of the assumptions made about how children’s bodies respond to coronavirus may turn out to be incorrect. In cases cropping up all over the world, children are showing signs of a mysterious inflammatory disease possibly linked to COVID-19.

Doctors in Italy started noticing something suspicious in February and March when more than 10 children came in with symptoms that seemed to be Kawasaki disease, an inflammatory disorder, in two months, reported the New York Times. While this number might feel inconsequential, Kawasaki disease is extremely rare, and 10 cases in such a short period of time is more than 30 times the rate of new cases than doctors would have predicted. This unusual uptick was the red flag that got Italian scientists ready to investigate, according to the Times. The results of their research were released last week in the journal The Lancet.

What the Italian researchers found was that, while none of the children in the study died, their symptoms were dramatically worse than those associated with Kawasaki disease. According to the study, half of the children with this Kawasaki-like disease went into shock, they were likely to have heart complications, and they frequently needed steroid treatment in order to recover, reported the Times. This mystery ailment was linked to COVID-19 when the children were tested for novel coronavirus antibodies. Eight out of the ten children reportedly developed antibodies, and doctors aren’t sure about the other two, as some of the treatments the children underwent may have interfered with effective testing.

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On Friday, the World Health Organization (WHO) released a statement about what they are calling this, “multi-system inflammatory syndrome,” (or "pediatric multi-system inflammatory syndrome") possibly linked to novel coronavirus infection. The statement serves as both an announcement to the public and as a call to arms for researchers to be on the lookout for children with these new symptoms that could be linked to COVID-19. "A causal connection between the virus and the new illness has yet to be proven," Charles Schleien, chair of pediatrics at Northwell Health in New York, told USAToday. But the link between to the two appears strong.

WHO’s statement reiterates that because children’s bodies and immune systems are still developing, the symptoms that they show as a result of coronavirus exposure are different than adults, but these symptoms can still be severe and, sometimes, lethal.

Children may have multisystem inflammatory syndrome if they have a fever that lasts more than three days, at least two of the unique symptoms (like rash and shock), have measurable markers of inflammation, and have been exposed to COVID-19. This disease seems to be affecting predominantly school-aged children from about age three to adolescence, according to WHO’s statement. Doctors at Imperial College London in the U.K. are working at lightning speed to find treatment for this syndrome, reported the Guardian.

The novel coronavirus is just that — novel — and so many of the assumptions that we’ve made about how it affects our bodies and spreads have been off. I hope that it doesn’t take too many of these sad reminders to quell our hubris. “We’ve got to be careful that we are not cavalier and thinking that children are completely immune to the deleterious effects,” Anthony Fauci said in a Senate hearing last week.