Fatal Multisystem Inflammatory Syndrome in Adult after SARS-CoV-2 Natural Infection and COVID-19 Vaccination.

We describe a fatal case of multisystem inflammatory syndrome in an adult with onset 22 days after a second dose of mRNA coronavirus disease vaccine. Serologic and clinical findings indicated severe acute respiratory syndrome coronavirus 2 infection occurred before vaccination. The immunopathology of this syndrome, regardless of vaccination status, remains poorly understood.