My great-uncle, in 2021, was extraordinarily healthy for a 92-year-old. Shortly after he got vaccinated for Covid (he didn't want to, but his wife forced him), he began exhibiting symptoms of dementia.
Then, in May 2023, he was diagnosed with lung cancer (again), which quickly spread to his entire body. A few weeks later, he was given the "terminal illness" talk and given three months to live, dying in October of that year.
When I say he was very healthy for his age, I mean it. He could still walk unassisted, never needed glasses, hardly looked his age, quickly bounced back from many illnesses that could easily kill someone only half his age (Legionnaire's Disease, pneumonia, a brain aneurysm, congestive heart failure, his first battle with lung cancer, etc.) ...the list goes on.
But as soon as he got the shot, he went downhill at such an alarmingly fast speed that we all knew it couldn't have been a coincidence. Only his widowed wife remains in denial; the rest of my family all collectively decided to just not bring it up.