Syncope after COVID-19 Vaccination in a Young Man with Unmasking Brugada Syndrome.

A 23-year-old man with no significant medical history was rushed to a hospital due to transient loss of consciousness with incontinence. The patient had developed a fever after his second dose of coronavirus disease 2019 (COVID-19) vaccine, and the patient was found groaning in bed approximately 40 hours after the vaccination in the early morning. The patient was diagnosed with Brugada syndrome (BrS) based on a drug-provocation test. His father had been diagnosed with BrS and died suddenly at 51 years of age. Young adults with a family history of BrS should be cautioned about fever following COVID-19 vaccination.