What you need to know

Children who get COVID-19 may later develop a rare complication called multisystem inflammatory syndrome in children (MIS-C). This condition can be confused with severe COVID-19, and when it was first discovered, it was misdiagnosed as Kawasaki disease because the conditions have shared symptoms, such as inflammation and fever. They are now recognized as clinically distinct, but similarities between these conditions mean that doctors and researchers need a better way to know when a child has severe COVID-19, has developed MIS-C, or may have another condition altogether.

In a study supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), researchers found that patients with MIS-C had specific biomarkers of cell injury and death that were distinct from those of patients who had COVID-19.

What did the researchers do?

The researchers collected 416 blood and/or plasma samples from 237 children who were patients at three medical centers. The children had been diagnosed with MIS-C following COVID-19, had COVID-19 without MIS-C, or were healthy.

Using molecular sequencing of blood and plasma RNA and plasma DNA, the researchers compared the samples between the three groups. These tests revealed that COVID-19 and MIS-C produced different types of cellular injury and death. The researchers also found cell types associated with MIS-C that had not been seen before.

Why is this research important?

Now that researchers can better tell the differences between COVID-19 and MIS-C, it may be possible to research new diagnostic tests that can differentiate between MIS-C and severe COVID-19 or other inflammatory diseases, such as Kawasaki disease, septic shock, and toxic shock syndrome. Identifying and tailoring treatments for those conditions will lead to improved outcomes for children who are affected by them.

Where can I go to learn more?

Biomarker pattern found in kids with COVID 19-linked inflammatory syndrome

• NIH shares more details about the study, which is supported by NICHD.

When Kids Get Sick After COVID-19 Goes Away

• NIH is following children with MIS-C for five years to understand this COVID-related illness.

Kawasaki Disease

• Kawasaki disease is a disease of unknown origin that affects children under 5 years of age, with symptoms similar to MIS-C.

Sources

Loy, C. J., Sotomayor-Gonzalez, A., Servellita, V., Nguyen, J., Lenz, J., Bhattacharya, S., Williams, M. E., Cheng, A. P., Bliss, A., Saldhi, P., Brazer, N., Streithorst, J., Suslovic, W., Hsieh, C., Bahar, B., Wood, N., Foresythe, A., Gliwa, A., … & Chiu, C. Y. (2023). Nucleic acid biomarkers of immune response and cell and tissue damage in children with COVID-19 and MIS-C. Cell Reports Medicine. Advance online publication. https://doi.org/10.1016/j.xcrm.2023.101034