Study: Most children recover within 6 months after severe MIS-C following COVID-19 infection

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A new study on multisystem inflammatory syndrome in children (MIS-C) following COVID-19 infection has found that most young patients recover within 6months, with significant improvements in both heart function and overall health. The findings, published in JAMA Pediatrics, provide reassuring evidence about the midterm outcomes for children affected by this rare but serious condition.

MIS-C is a potentially life-threatening inflammatory response that can occur weeks after a COVID-19 infection. It primarily affects children and young adults, causing fever, inflammation, and multi-organ dysfunction. While previous research focused on short-term effects, this new study examined health outcomes over a 6-month period.

The research team, led by Dongngan Truong, MD, Emory University School of Medicine, followed 1,204 children diagnosed with MIS-C at 32 pediatric hospitals across North America. The study tracked their recovery from March 2020 to January 2022, collecting data on heart function, overall health, and quality of life.

One of the study’s key findings was that nearly all children with heart complications from MIS-C experienced full recovery within 6 months. During hospitalization, 42.3% of children in the study had a reduced heart function, known as left ventricular ejection fraction (LVEF) below 55%. However, by 6 months, all but 1 patient had regained normal heart function.

Additionally, among the small subset of patients who developed coronary artery aneurysms, 92.3% showed complete normalization of their artery dimensions by 6 months. Only 1 child had a persistent large or giant aneurysm.

The study also assessed how children felt physically and emotionally over time. By 6 months, 95.1% of participants reported that they had regained at least 90% of their pre-illness health. Fatigue, which was the most commonly reported symptom at 2 weeks post-hospitalization (15.9%), dropped significantly to just 3.4% by 6 months.

"By the 6-week visit, health measures were at least equivalent to pre-pandemic population norms, and at 6 months, they were often even better," the authors noted in the study.

The study also highlighted racial disparities in MIS-C outcomes. Children of non-Hispanic Black race were found to have lower LVEF during hospitalization compared to other racial groups. Higher levels of inflammation markers, such as C-reactive protein and troponin, were also associated with lower heart function during the acute phase.

"[The study] results suggest that cardiovascular and noncardiovascular morbidities were rare by 6 months after hospital discharge, despite severe illness in many patients during the acute phase," noted the authors. "The longer-term health implications of MIS-C are unknown, and continued surveillance of study participants is ongoing to characterize their health status up to 2 years after illness onset."

Reference:

Truong DT, Trachtenberg FL, Hu C, et al. Six-Month Outcomes in the Long-Term Outcomes After the Multisystem Inflammatory Syndrome in Children Study. JAMA Pediatr. Published online January 13, 2025. doi:10.1001/jamapediatrics.2024.5466