Safety of SARS-CoV-2 vaccine in children with a history of Multisystem Inflammatory Syndrome (MIS-C)

In May 2020, the WHO warned of the occurrence of a multisystem inflammatory syndrome associated with COVID-19 infection (MIS-C) in the pediatric population. Objective: To determine the safety of the SARS-CoV-2 vaccine in Chilean children previously hospitalized due to MIS-C. Patients and Method: Descriptive study on patients with history of MIS-C, discharged from the Hospital Dr. Exequiel Gonz & aacute;lez Cort & eacute;z in Santiago, Chile, between March 2020 and December 2022 who later received the SARS-CoV-2 vaccine. The number of doses, date of each vaccination, time interval to diagnosis of MIS-C, and the type of vaccine received in the period studied were reviewed. A questionnaire was administered on symptoms and adverse events presented by patients in the period up to 12 weeks after each vaccination, as well as symptoms suggestive of recurrence of MIS-C. Patients who could not be contacted, did not want to participate, or were not susceptible to vaccination were excluded. Results: 50 patients were included, the median age was 5.2 years, 58% were male, and 68% required PICU admission. 82% received at least 1 dose of a SARS-CoV-2 vaccine. The time (median) between MIS-C diagnosis and the first dose of the SARS-CoV-2 vaccine was 15 months (0-24). No serious adverse events or recurrence of MIS-C were reported. Conclusion: Vaccination against SARS-CoV-2 was safe, regardless of age, clinical manifestation of MIS-C, course, type of vaccine, and interval between illness and vaccination. Thereby, the interval for vaccination after MIS-C could be less than 3 months.