Most Kids With COVID-Linked MIS-C Recover by 6 Months

The most common symptoms reported at 2 weeks were fatigue (15.9%) and low stamina/energy (9.2%); both decreased to 3.4% and 3.3%, respectively, by 6 months. The most common cardiovascular symptom at 2 weeks was palpitations (1.5%), which decreased to 0.6%.

Chest Pain Increased Over Time

Reports of chest pain, however, reportedly increased over time, with 1.3% reporting chest pain at rest at 2 weeks and 2.2% at 6 months. Although gastrointestinal symptoms were common during the acute MIS-C, only 5.3% of respondents reported those symptoms at 2 weeks.

Children in the cohort had a median age of 9 years, and 60% were men. They self-identified with the following races and ethnicities: American Indian or Alaska Native (0.1%), Asian (3.3%), Black (27.0%), Hawaiian Native or Other Pacific Islander (0.2%), Hispanic or Latino (26.9%), multiracial (2.7%), White (31.2%), other (1.0%), and unknown or refused to specify (7.6%). Authors wrote that the cohort was followed-up to 2 years after illness onset and long-term results are not yet known.

Time to Exhale

David J. Goldberg, MD, with the Cardiac Center, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, and colleagues, wrote in an accompanying editorial that “the decreased frequency of the disease along (with) the reassuring reports on midterm outcomes can allow the pediatric community a moment of collective exhale.”

The editorialists note that of those who initially presented with myocardial dysfunction, all but one patient evaluated had a normal ejection fraction at follow-up. Energy, sleep, appetite, cognition, and mood also normalized by midterm, they note.

“The results of the MUSIC study add to the emerging midterm outcomes data suggesting a near-complete cardiovascular recovery in the overwhelming majority of patients who develop MIS-C,” Goldberg and colleagues wrote. “Despite initial concerns, driven by the severity of acute presentation at diagnosis and longer-term questions that remain (for example, does coronary microvascular dysfunction persist even after normalization of coronary artery z score?), these data suggest an encouraging outlook for the long-term health of affected children.”

The Centers for Disease Control and Prevention and other agencies have reported a declining overall incidence of MIS-C and highlighted the protective value of vaccination. 

The editorialists add, however, that while the drop in MIS-C cases is encouraging, cases are still reported, especially amid high viral activity periods, “and nearly half of affected children continue to require intensive care in the acute phase of illness.”

Truong reported grants from the National Institutes of Health and serving as coprincipal investigator for Pfizer for research on COVID-19 vaccine-associated myocarditis funded by Pfizer and occurring through the framework of the National Heart, Lung, and Blood Institute’s Pediatric Heart Network outside the submitted work. 

Coauthor disclosures are as follows: Audrey Dionne, MD, reported grants from Pfizer and Boston Scientific outside the submitted work. Daniel Forsha, MD, reported receiving grants from Additional Ventures Foundation outside the submitted work. Brian McCrindle, MD, MPH, reported receiving consultant fees from Amryt Pharma, Chiesi, Esperion, and Ultragenyx outside the submitted work. R. Mark Payne, MD, reported receiving consultant fees from Larimar Therapeutics for mitochondrial therapies outside the submitted work. Divya Shakti, MD, reported being an employee of Takeda Pharmaceuticals since July 2023. 

Editorialist Anna Costello, MD, reported grants from Childhood Arthritis and Rheumatology Research Alliance and the Arthritis Foundation, Academy Health, and the Gordon and Betty Moore Foundation during the conduct of the study.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune, Science News, Northwestern magazine, and Nurse.com and was an editor at the Chicago Sun-Times, The Cincinnati Enquirer, and St. Cloud Times.