Multisystem inflammatory syndrome in children (MIS-C)

Affects many body systems, Children and teens, Infections. Also called: MIS-C.

How common is Multisystem inflammatory syndrome in children (MIS-C) in the US?

MIS-C cases reported to CDC's national passive surveillance system with illness onset in 2023: 0.11 cases per million person-months (US child population, expressed per million person-months (bridged-race 2020 Census population estimates); United States (CDC national MIS-C surveillance), 2023). Source: MMWR Morbidity and Mortality Weekly Report (CDC), 2024. Label: VERIFIED.

• 0.11 cases per million person-months MIS-C cases reported to CDC's national passive surveillance system with illness onset in 2023. Out of: US child population, expressed per million person-months (bridged-race 2020 Census population estimates). Where: United States (CDC national MIS-C surveillance). When: 2023. Label: VERIFIED.

  Overall MIS-C incidence in 2023 was 0.11 cases per million person-months (95% CI = 0.10–0.14), representing an 80% decline in incidence compared with that during April–December 2022 (0.56 cases per million person-months; 95% CI = 0.51–0.62), and a 98% decrease from the peak of 6.79 (95% CI = 6.56–7.03) early in the COVID-19 pandemic (October 2020–April 2021).

  Source: Notes from the Field: Surveillance for Multisystem Inflammatory Syndrome in Children - United States, 2023. MMWR Morbidity and Mortality Weekly Report (CDC), 2024. PubMed 38488279. DOI 10.15585/mmwr.mm7310a2.

Each figure measures something different. Do not compare them with each other or with other conditions.

Medical codes

• ICD-10-CM FY2026: M35.81 Multisystem inflammatory syndrome (broader). The code title has no age limit, so it is broader than the pediatric form.

Research activity

As of 2026-09-24: 37 registered studies on ClinicalTrials.gov (search Multisystem Inflammatory Syndrome in Children) and 2,038 PubMed records, 2021 to 2025. A count of records is not how common or serious the condition is.

Population information, not medical advice. Methodology · Known limitations