Some vaccinated youngsters in the 12–20 age group have reported a hyper-inflammatory condition where the body’s immune system goes into overdrive and shows symptoms of fever and systemic inflammation involving multiple organ systems, according to a study published Tuesday.
There were a total of 5,973 cases of Multisystem Inflammatory Syndrome in Children (MIS-C) reported to the MIS-C national surveillance system of the U.S. Centers for Disease Control and Prevention (CDC) between May 14, 2020, and Nov. 30, 2021.
MIS-C usually manifests two to six weeks after inoculation and is characterized by severe illness that requires hospitalization.
The authors of the peer-reviewed Lancet study looked into data between Dec. 14, 2020, and Aug. 31, 2021, and “identified 21 individuals with MIS-C after COVID-19 vaccination.”
Those 21 individuals were aged between 12 and 20 years old, with 13 individuals male and eight female. Eleven of them developed MIS-C after receiving the first dose of the vaccine, with the remaining 10 developing the illness after taking the second dose.
“All 21 were hospitalized: 12 (57 percent) were admitted to an intensive care unit and all were discharged home. 15 (71 percent) of 21 individuals had laboratory evidence of past or recent SARS-CoV-2 infection, and six (29 percent) did not,” the report said.
In total, over 21 million 12 to 20-year-old individuals had received at least one dose of a COVID-19 vaccine as of Aug. 31, 2021, putting the rate of MIS-C among this age group at one per million. The reporting rate among those without evidence of COVID-19 infection was only 0.3 per million vaccinated individuals.
These rates are lower than a previous study on the issue that had proposed an MIS-C reporting rate of 224 per million among individuals aged 11 to 15 and a rate of 164 per million among those aged between 16 and 20.
“The pathogenesis of MIS-C is hypothesized to involve a dysregulated immune response to SARS-CoV-2 infection, and host genetics might alter susceptibility to developing MIS-C,” the authors wrote.