A recent study published in the journal JAMA Pediatrics this week found that most of the children who developed MIS-C following a COVID-19 infection either had no or only very mild symptoms of the coronavirus. 

In fact, the study found that about 75% of the patients studied did not experience COVID-19 symptoms when they had a coronavirus infection. 

However, when those same patients later developed the inflammatory condition weeks later, they did experience common symptoms associated with MIS-C, such as fever.

“In this cross-sectional study of a large cohort of patients with MIS-C, 2 peaks that followed COVID-19 peaks by 2 to 5 weeks were identified. The geographic and temporal association of MIS-C with the COVID-19 pandemic suggested that MIS-C resulted from delayed immunologic responses to SARS-CoV-2 infection. The clinical manifestations varied by age and by presence or absence of preceding COVID-19,” the study outlines.

The study, led by researchers at the US Centers for Disease Control and Prevention (CDC), came to that conclusion after studying nearly 1,800 causes of MIS-C reported to the CDC between March 2020 and mid-January 2020. The study included children up to age 20, although the majority of the study participants were under 15.

MIS-C has been likened to Kawasaki disease, which is common in children younger than 5 years old and causes inflammation of blood vessels throughout the body. 

Kawasaki disease typically causes a fever, as well as a rash, sore throat and swollen lymph glands. Symptoms of MIS-C include fever, abdominal pain, diarrhea, vomiting, skin color changes, rashes and labored breathing.

The latest data by the CDC shows that there are at least 3,185 cases of MIS-C in the US and 36 associated deaths.

The CDC recommends contacting your child’s doctor, nurse or clinic immediately if your child shows any symptoms of MIS-C. Emergency services should also be sought immediately if your child shows any other warning signs like trouble breathing, pain or pressure in the chest, new confusion, the inability to stay awake, severe abdominal pain or pale colored skin, lips or nail beds.