Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe condition associated with SARS-CoV-2, which causes COVID-19. It typically occurs 2-6 weeks after a child has been infected with SARS-CoV-2, even if the initial infection was mild or asymptomatic and went unrecognized. MIS-C is characterized by inflammation in various body parts, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal tract. Although most children with MIS-C recover with medical care, it can be severe and even fatal.
The Centers for Disease Control and Prevention (CDC) is actively working to understand why some children develop MIS-C after SARS-CoV-2 infection while others do not. CDC is also investigating if specific variants of SARS-CoV-2 are more likely to cause MIS-C or if confident children are more susceptible to developing this condition. While collaborating with state, local, and territorial health departments, U.S. and international scientists, healthcare providers, and other partners, CDC is monitoring and studying MIS-C to gain more insights into this condition.
A new study published by the National Institutes of Health provides reassurance that COVID-19 vaccination is safe for children and adolescents who have previously experienced multisystem inflammatory syndrome (MIS-C). The study, which is the largest to examine COVID vaccination in this group, involved 385 patients aged five years or older with prior MIS-C who were eligible for COVID-19 vaccination.
Of this group, 185 (48.1%) received at least one vaccine dose. The median age of the participants was 12.2 years, and 73.5% were male. The participants were racially diverse, 24.3% Black, 31.9% Hispanic, and 28.6% White. The median time from their MIS-C diagnosis to their first vaccine dose was nine months.
The study found no reports of serious complications, including myocarditis or recurrence of MIS-C, in children and adolescents who received a COVID vaccination following MIS-C. About half of the participants experienced mild and typical reactions, such as arm soreness and fatigue, similar to reactions reported in the general population after COVID vaccination. The findings support the CDC’s recommendation that patients with a history of MIS-C receive a COVID vaccine at least 90 days after diagnosis and that it is safe.
“The results reassure us, and this safety data should be comforting to families and healthcare professionals when considering and recommending vaccination,” said study co-leader Dr. Matthew D. Elias, a pediatric cardiologist at Children’s Hospital of Philadelphia and clinical assistant professor of pediatrics at the University of Pennsylvania.
Dr. Audrey Dionne, a pediatric cardiologist at Boston Children’s Hospital and assistant professor of pediatrics at Harvard Medical School, played an important role in spearheading the investigation. The researchers have continuously provided care for children with MIS-C throughout the outbreak.
The study’s authors emphasized the importance of developing, testing and implementing COVID-19 preventive and therapeutic medications in high-risk populations such as children and the general community. According to the Centers for Disease Control and Prevention, approximately 9,000 persons in the United States have been diagnosed with MIS-C, with 74 of them eventually dying. COVID vaccine appears to be protective against this rare disorder in those who have it, suggesting that the disease may be on the decline.
Long-term outcome studies are helpful because, while many patients with MIS-C recover completely clinically, some evidence indicates that chronic issues may persist after MIS-C. Children account for approximately 13% of all COVID cases in the United States, and the study is part of a wider NIH cooperative research initiative called CARING for Children with COVID.
