Sudden death associated with flare-ups of multiple sclerosis after COVID-19 vaccination:
https://jkms.org/DOIx.php?id=10.3346/jkms.2023.38.e78
A 19-year-old man
"1 day before the sudden death, the deceased said to his colleague “I cannot sleep well these days & I feel like I'm having a seizure at night”