Top 5 Takeaways

1. Continued incidence but decreasing trend of MIS-C: While the incidence of Multisystem Inflammatory Syndrome in Children (MIS-C) has decreased significantly from its peak early in the COVID-19 pandemic, cases continue to occur, notably after periods of increased COVID-19 activity.
2. High need for intensive care: About half of the reported MIS-C patients required intensive care unit–level care, underscoring the severity of the condition in a significant proportion of affected children.
3. Majority of cases in unvaccinated children: Over 80% of MIS-C cases were in vaccine-eligible but unvaccinated children, highlighting the importance of COVID-19 vaccination for prevention.
4. Age shift and clinical characteristics: A shift to a younger median age of MIS-C patients has been observed in 2023 compared to previous years, along with a slight evolution in clinical characteristics.
5. Recommendations for vaccination: The report emphasizes the importance of staying up to date with COVID-19 vaccinations for children aged ≥6 months to prevent serious COVID-19 illness and complications, including MIS-C.

Original Article Author and Citation

Corresponding Author

Anna R. Yousaf, MD , pgy6@cdc.gov

Suggested Citation

Yousaf AR, Lindsey KN, Wu MJ, et al. Notes from the Field: Surveillance for Multisystem Inflammatory Syndrome in Children — United States, 2023. MMWR Morb Mortal Wkly Rep 2024;73:225–228.DOI: http://dx.doi.org/10.15585/mmwr.mm7310a2.

Summary

The report details the ongoing surveillance and incidence rates of Multisystem Inflammatory Syndrome in Children (MIS-C) in the United States for the year 2023. MIS-C is a serious condition that occurs after SARS-CoV-2 infection, characterized by fever and involvement of multiple organs. Despite a significant decrease from early pandemic levels, MIS-C cases persist, especially following increased COVID-19 activity, underscoring the need for continued surveillance and vaccination.

Methods

This surveillance included all reported MIS-C cases with illness onset during 2023, analyzing patient characteristics and estimating incidence rates. The study utilized 2020 population estimates for incidence calculations and considered COVID-19 vaccination status, with an emphasis on the importance of vaccination in preventing MIS-C.

Discussion

The discussion highlights the decrease in MIS-C incidence from the pandemic’s peak and a recent increase in cases among younger children. The persistence of MIS-C cases, particularly in unvaccinated children or those with waned immunity, points to the critical role of COVID-19 vaccination in prevention. The report also notes the shift in clinical characteristics of MIS-C cases over time.

Conclusion

Despite the decline in incidence, MIS-C continues to affect children, with a notable portion requiring intensive care. The findings emphasize the importance of COVID-19 vaccination among children to prevent MIS-C and the value of ongoing surveillance to monitor trends and inform public health strategies.

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