fb-pixel Skip to main content

What we know — and don’t — about the new child inflammatory syndrome linked to coronavirus

Boston Children’s Hospital is leading a nationwide, CDC-sponsored study of how COVID-19 causes severe illness in children, with an intense focus on understanding Multisystem Inflammatory Syndrome.

Boston Children's HospitalLane Turner/Globe Staff

In the initial weeks and months of the coronavirus outbreak, virtually all reports indicated it was sparing children. Pediatric cases accounted for fewer than 2 percent of total cases in the United States, and the majority of children who tested positive were asymptomatic or had mild symptoms. Parents breathed a collective sigh of relief.

Then, on April 27 the British National Health Service issued an alert about a multi-system inflammatory disease in children with COVID-19, based on a small number of cases in London and elsewhere. The alert cited features of toxic shock syndrome and Kawasaki disease, an acute childhood illness that causes inflammation of the blood vessels. Last week, the US Centers for Disease Control and Prevention, as well as several cities and states, also issued alerts.


“Multisystem Inflammatory Syndrome in Children” is described by the CDC as “a troubling new syndrome that may be associated with COVID-19.” In its alert, the CDC noted that there is limited information available about MIS-C.

Here is what we know today: Most children with MIS-C have persistent high fevers for three or more days, but then exhibit a range of symptoms in various combinations reflecting inflammation in multiple organs of the body. Because the illness is so new, symptoms are still being documented, and they can vary from child to child.

Specific presentations may include:

Toxic-shock-like symptoms Severe flu-like symptoms with high fever for several days, as well as a sunburn-like rash, low blood pressure, and an enlarged lymph node in the neck.

Kawasaki-like symptoms Rash; bloodshot eyes; red, swollen hands and feet; red, cracked lips; and a red, swollen tongue that looks like a strawberry.

Gastrointestinal symptoms Diarrhea, vomiting, abdominal pain, or a swollen abdomen.

Respiratory symptoms A persistent cough and shortness of breath, symptoms that have been reported with COVID-19, may or may not be present.


Thus far MIS-C appears to be relatively rare, and most children recover well. However, a small number of children have died.

If you think your child might have MIS-C, consult your pediatrician or health care provider immediately, especially if your child is unable to eat, drink, walk, or move around as before, or is having any chest pain or difficulty breathing. Symptoms may get worse quickly, so don’t delay seeking medical attention. Children with MIS-C need monitoring by pediatric specialists in infectious disease, rheumatology, critical care, and cardiology.

Why these cases are emerging only now, and what is causing them, is a mystery. MIS-C is still in an early stage, and we are moving quickly on a number of fronts to better understand it, guided in part by Dr. Jane Newburger, associate cardiologist in chief at Boston Children’s Hospital, and a longstanding expert on Kawasaki disease.

Dr. Adrienne Randolph, a senior critical care physician at Boston Children’s, is leading a nationwide, CDC-sponsored study of how COVID-19 causes severe illness in children, with an intense focus on understanding MIS-C.

Dr. Jeffrey Burns, our chief of Critical Care Medicine, is leading a regular call of pediatric health experts from around the world — as well as representatives of the World Health Organization, the National Institutes of Health, the CDC, and the European Commission — to share MIS-C clinical information in real time and foster collaboration.


These are just some of the important efforts underway that can serve as a foundation for what is urgently needed: a coordinated, global research and public health effort to better understand MIS-C and determine how best to treat it. Governments and other organizations must invest in clinical trials as well as data integration drawing on registries of children with COVID-19 and MIS-C.

There needs to be a better understanding of how children’s immune systems are responding, what genetic risk factors they may carry, why there is such a range of symptoms, and who is at greatest risk, especially as states look to reopen schools and child-care centers.

A robust reporting system is the cornerstone of an effective response to any public health crisis. More governments — at the national, regional, and state levels — need to establish mechanisms for health care providers to report the frequency and severity of new MIS-C cases. Massachusetts recently announced a requirement for mandatory reporting of any confirmed or suspected cases in patients younger than 21. Last week’s CDC alert included a similar directive.

Partnerships among health care providers and schools and child-care centers should be strengthened to track new cases and monitor the spread of the syndrome. In addition, researchers need to investigate the long-term impacts of MIS-C on children. More broadly, Boston Children’s has already initiated more than 100 scientific, clinical, therapeutic, epidemiological, and vaccine research projects to better understand COVID-19, particularly how it affects children.


Children are not little adults. They have unique vulnerabilities and responses to illness that require specialized care and dedicated research.

The more we study, the more we learn, and the more we share, the better we will understand COVID-19 and MIS-C, and the better we can protect the health and well-being not only of our children but of our entire population.

Sandra L. Fenwick is chief executive officer of Boston Children’s Hospital.