MIS-C: A New Name For Covid Kawasaki/Toxic Shock In Young People

There is a new name for a recently recognized set of Covid-19 related symptoms in children and adolescents. The World Health Organization and the US Centers for Disease Control and Prevention have assigned the name Multisystem Inflammatory Syndrome in Children or MIS-C to this disease. The name attempts to encompass the many facets of the disease in young people.

MIS-C symptoms may include skin rashes, reddening of the toes and fingers, shortness of breath, fever, diarrhea muscle aches and fatigue. The symptoms regularly appear late in the course of the disease. Young people who may have only mild symptoms following initial infection and then appear to fully recover, sometimes experience the symptoms of MIS-C several weeks later. Life-threatening symptoms like heart failure may have a sudden and unexpected onset, requiring immediate life support.

Initially young children, except those with serious underlying diseases, were thought to be largely unaffected or experience only mild symptoms following SARS-CoV-2 infection. That picture is rapidly changing with the realization of late onset life- threatening disease in children and adolescents. MIS-C is still believed to be an infrequent outcome of infection. This may or may not prove to be the case as we learn more about the long term effects of the disease in children in young people.

The name MIS-C attempts to summarize our current understanding of the syndrome.

The term Multisystem reflects the recognition that many organs in the body may be involved. The affected organ systems differ from person to person. Only one or many organs may be affected in a single individual. Organs affected include the heart, kidney, lung, skin, blood, blood vessels as well as gastrointestinal and nervous systems.

The name Inflammatory reflects what many believe to be an underlying cause, inflammation of the organs and specific tissues. One hallmark of the disease is elevation of markers of generalized inflammation in the blood. Red toes and fingers may also reflect inflammation of blood vessels.

Syndrome is a word used to describe a diverse set of signs and symptoms the cause of which is not definitely known. The term fits loosely here as the primary cause is infection by SARS-CoV-2, the virus that causes Covid-19.

MIS is followed by “-C”. The C stands for child. The collection of symptoms has been observed mostly in young and adolescents 15 or younger. A similar set of late onset symptoms have been observed in young adults up to the age 30.

It may be the “-C” will eventually be modified, as the late consequences of Covid-19 are only now being fully understood in patients of all ages. It is not uncommon for adults to continue to experience Covid related symptom for many weeks past initial recovery. Relapses with a complex sets of symptoms including fever and even continued virus detection have been noted.


A schoolboy wearing a protective mouth mask and a face shield attend a course in a classroom at Claude Debussy college in Angers, western France, on May 18, 2020 after France eased lockdown measures to curb the spread of the COVID-19 pandemic, caused by the novel coronavirus. (Photo by Damien MEYER / AFP) (Photo by DAMIEN MEYER/AFP via Getty Images)


The realization that school age children and adolescents may also suffer serious and life-threatening consequences is causing some to reevaluate the wisdom of opening summer camps and re-opening schools in countries and communities were new infections persist.

Let’s remember we are still less than half a year into the pandemic. Even so, we are beginning to learn it is far more complex than a simple pneumonia both in the short and long term. We have yet to understand the full impact of infection on a body any age.

For those interested in learning more about our emerging understanding of MIS-C, consider the following resources:

This article in the Guardian describes attempts to provide blood tests that will assist doctors in diagnosing young people who either have MIS-C or are at risk. They will test the blood of children known to be infected by SARS-CoV-2 for markers of inflammation. I suggest that this test be used for adults too. Please note that the article describes “hundreds” of children in Europe with MIS-C.

This article from the Michigan Health Lab is a clear description of MIS-C. Required reading to understand the disease.

This link is from the US Centers for Disease Control and Prevention and summarizes childhood Covid-19.

This story in the Washington Post describes a single instance of Covid in a child.

Happily, this hair-raising story ends well.

This story in the New York Times is a vivid description of what Covid related MIS-C can feel like to an adolescent. This is an important story for parents, grandparents, and everyone under 30 to read.

This article originally appeared on Forbes (May 18, 2020).

© William A. Haseltine, PhD. All Rights Reserved.