This is a familiar, if less common, bad vex outcome. I've known for years a fellow who was an Occupational Medicine nurse practitioner, in his mid-50's, former military, and still an elite athlete. He worked for an Occupational Medicine clinic (my main competitor), and was required to take the C19 vex in mid 2021 IIRC. He soon developed sudden onset, rapidly progressive dementia. Within a span of several months he went from normal health, to being no longer able to function as a nurse practitioner and was totally disabled from dementia.

My suspicion is that the shot promoted the development of prion disease, and that was the end of him.

--Lunar Apprentice