Comment by blagie

The scientists said it was causation.

    "We found that flu vaccination in older adults reduces the risk of 
     developing Alzheimer’s disease for several years. The strength of 
     this protective effect increased with the number of years that a 
     person received an annual flu vaccine – in other words, the rate 
     of developing Alzheimer’s was lowest among those who consistently 
     received the flu vaccine every year"

Yes, that's in an interview for the article. That's the reason (1) the general public misunderstands (2) people scream about it. Scientists get points for "high-impact research," and there is strong incentive to be dishonest.

(As a footnote, personally, I do believe it is causation; I believe that as with COVID and EB, we've dramatically underestimated the long-term impact of many viral infections. But that's just a personal belief.)