The technical term is multisystem inflammatory syndrome in children, or MIS-C. It’s a generalized immune system reaction to an unknown foreign object, and it can be deadly. There’s an adult version as well, but less is known about it. In children, the average age of victims is 8 years.
An article in The Atlantic that appeared online this morning describes how the disease works. While the number of child deaths linked to MIS-C in 2020 (several hundred) was a small fraction of total fatalities, this is likely to be more of a problem with the Delta version we have now, for several reasons:
- Delta tends to impact younger people.
- Those under the age of 12 have no vaccine.
- We are relaxing rules on masking and social distancing.
Typical symptoms include rash, conjunctivitis, low blood pressure, diarrhea and/or vomiting. At this time, roughly 4,000 children are known to have the disease and there is no cure.
The disease in children has been associated with a protein, zonulin, which makes the intestines more permeable (“leaky”). We know that the coronavirus can live in the gut long after a patient tests negative for it. The gut may play a role in the lag that exists between the start of COVID-19 symptoms and onset of MIS-C, and a leaky gut could send the virus into the bloodstream. It is also possible that the role of the gut could explain Long Covid.
A medication for celiac disease that targets zonulin was shown in the case of one severely ill toddler to be effective against coronavirus-based MIS-C. While one case isn’t proof, it supports the idea that zonulin and the gut is central to this disease.
A key element of the immune system is a port on each cell called a T-cell receptor. A class of “superantigens” (like the spike protein of the coronavirus) bind to these receptors in an odd way that prevents the receptor from identifying them. That creates a confused, nonspecific and sometimes excessive response by the body that itself can be quite harmful.
Toxic shock syndrome, identified years ago and associated with the use of super-absorbent tampons, works in much the same way. Both the COVID illness and the tampon-related illness were originally misidentified as Kawasaki disease.
- Khamsi, Roxanne, “COVID-19’s Effects on Kids Are Even Stranger than We Thought,” The Atlantic, July 15, 2021.