Shingles (Herpes zoster) is implicated. The whole 'lifelong nervous system infection' does seem a bit awful. I bet if we chip away at new kinds of herpes viruses, we'll find a fairly drastic reduction in Alzheimers.

"There is mounting evidence that herpes [simplex] leads to Alzheimers" https://www.bbc.com/future/article/20181022-there-is-mountin...

How about HSV-1/2? Combined this virus is present in about 2/3 people in the US, and resides dormant near the brain (cold sores).

I thought there's already a strong link with HSV and Dementia, is there any more research looking at this virus and a vaccine?

Summary: Wales used a cutoff date in 1933 to set eligibility for the vaccine: born before, ineligible; born after, eligible. The authors analyzed dementia rates in the populations born one week before and one week after and found a significant decrease in the vaccination population born one week after.

Given the unlikelihood of any other salient differences in the two populations (they were all born within 14 days of each other), they conclude that the vaccine had prophylactic effects against dementia and further conclude that Alzheimer’s may be caused by a virus.

That seems like a big deal!

Related reading on this topic: https://www.hardtowrite.com/pathogens/

The most interesting thing that I saw was: "We find strong protective effects of the vaccine for women but none for men, and that this diff is driven by Alzheimer’s (not vascular) dementia."

I've been meaning to get around to getting the shingles vaccine. I was all set to head out the the pharmacy to get it immediately until I read that..

Similarly, there is now extemely strong evidence that the Epstein-Barr is causal in multiple sclerosis. The vast majority of people are infected with EB, with most never having symptoms. However, a nonsignificant minority aren't. A large-scale study of data covering 10 million US military service people found that those infected with EB were 32 times more likely to develop MS.

This would not explain the precipitous rise in Alzhemier's rates seen in developed countries and mostly in the last few decades. I maintain that alzheimer's is type 3 diabetes.

> We found clean, CAUSAL evidence that the shingles vaccine prevents a good chunk of dementia cases. So, could a virus cause Alzheimer’s > YES

Not to be pedantic, but the BCG vaccine is used as treatment for bladder cancer but nobody is claiming that Tuberculosis causes bladder cancer. In order to claim that shingles is causal (rather than that the vaccine affects immune/other function), you would have to fulfill Koch's postulates or measure virus levels in various patients.

The effect is still interesting.

I wonder if there’s some kind of connection to the APOE4 genotype?

Serious déjà vu did I not read about this study a year ago on HN? I can see this is recent in date but can't shake the feeling...

https://pubmed.ncbi.nlm.nih.gov/35434253/ perhaps this

At my annual mandatory physical yesterday my doctor told me that there's a new shingles vaccine that's around 90% effective as opposed to the 60-70% effectiveness of the previous vaccine. It's a two-shot vaccine as opposed to the single shot for the old one. I turned it down, but will probably ask for it now. I got the previous vaccine a few years ago, and then got shingles a few months later, although it was a fairly mild case and I assume that the vaccination probably had a positive effect on that outcome. The funny thing is that I recognized the incident as shingles, and called for an appointment immediately and informed them of my suspicion. At my appointment two days later the doctor prescribed some anti-viral pills and said they were best started immediately after recognizing the infection. I started laughing, as did he.

I recently read some speculation that Alzheimer's might be related to prion diseases like wasting and mad cow disease. That's one possible explanation for cattle mutilations also, which is a really weird rabbit hole to go down.

Sounds like we should try to eliminate all long term infections just to be sure, even if they seem mild or harmless.

This – a thousand times, this.

I spent 5-6 years dealing with something like long-covid (only it started before covid). It had symptoms that seemed clearly related to an infection, but I also noticed effects that were similar to Alzheimer/dementia. Specifically sundowning.

I would become unthinkably exhausted and my mood would change drastically between the hours of about 5:00 and 8:00pm. Later in the evening, things would magically start clear up and I'd feel closer to normal.

That was, by far, the worst period of my reasonably long life, and it's still not something I'm over, I can just manage it much better. If anyone is dealing with something similar, I'm happy to talk about things that have worked for me.

Biggest fear in life for me is Alzheimer's or something similar. Looks like I'll be getting the shingles vaccine :)

Will be interesting to see the study go through the peer reviewed process & whether it will be published by a journal.

This seems like a math artifact caused by splitting into two groups and then curve fitting the two groups separately. Those two curve fits don't line up at the discontinuity but there's no reason to expect that they would.

The image in tweet 8 is really the damning one. It shows a big gap, but if you fitted the entire set it'd be nearly a straight line with a tiny blip caused by the vaccine.

Ben Recht is skeptical: https://twitter.com/beenwrekt/status/1662124696186544128

Very interesting. I recently watched the Michael J. Fox documentary(Still) and even he commented on an earlier infection as a teen "could've" been linked to his condition, but we'll never know.

Also having gone through two extended bouts of long covid now, I think it reactivated a family history of rheumatoid arthritis in me temporarily although I've never formally been diagnosed with it or struggled with it.

We're all just walking balls of disease causing germs eh?

Yet another reason to try to avoid getting infected with diseases. A 'stronger' immune system (which is really only 'stronger' at defending against the disease that you just caught!) isn't worth the risk of long-term side effects from a chronic infection.

Did a quick Google search, and it appears that this isn't a new hypothesis, and previous studies had conflicting results.

That seems to be relevant and in direct contradiction: https://www.alzheimersresearchuk.org/no-link-between-shingle... While this is only a correlational result, well, while correlation does not mean causation, you really can't have causation without correlation. So it seems there are conflicting results.

Let's see if this new result holds up. FWIW I'll still certainly get my shingles vaccine once I'm old enough to fall into the recommendation. Shingles is known to be a nasty disease, and making it less likely to get is by itself probably more than enough reason to get the vaccine.

https://www.medscape.com/viewarticle/975400 is interesting and seems to directly contradict what is claimed here.

"Herpes zoster does not appear to increase dementia risk ― on the contrary, the viral infection may offer some protection, a large population-based study suggests."

Conclusion aside, I enjoy reading research finding in this format - straight to evidence, short.

Massive hidden variable possibilities. Scientific discipline has been shitty for so long. It's exhausting. Beyond that, I wouldn't exactly call a 20% reduction evidence of direct cause.