M Levy et al. JAMA. Published online December 20, 2021. doi:10.1001/jama.2021.23262. Open Access: Multisystem Inflammatory Syndrome in Children by COVID-19 Vaccination Status of Adolescents in France

Key findings:

• From September 1, 2021, to October 31, 2021, a total of 107 children with MIS-C were hospitalized in France…33 (31%) were adolescents eligible for vaccination
• Among those with MIS-C, 0 had been fully vaccinated, 7 had received 1 dose with a median (IQR) time between vaccine injection and MIS-C onset of 25 (17-37) days, and 26 had not been vaccinated. The HR for MIS-C was 0.09 (95% CI, 0.04-0.21; P < .001) after the first vaccine dose compared with unvaccinated adolescent. Because there were no MIS-C cases in those who were vaccinated, an HR cannot be calculated in this group.
• The study had limitations, including the low number of patients, use of national data to calculate HR without considering regional variations, and inability to control for individual risks of MIS-C, such as sex, race and ethnicity, and comorbidities

My take: This study indicates that COCID-19 vaccination likely results in a marked decrease in the risk of MISC-C. This finding provides an additional reason favoring vaccination in adolescents in terms of risk-benefit calculation for immunization.

12/27/21: CDC Updates and Shortens Recommended Isolation and Quarantine Period for General Population