Shingles vaccination prevented or delayed dementia
21 comments
·December 5, 2025CrossVR
I wonder when we'll finally accept that there's no such thing as a harmless latent disease. Chickenpox, EBV, HPV, they're all associated with either neurodegeneration or cancer.
We should be vaccinating kids against all of them rather than sending them to Chickenpox parties.
dd8601fn
Too bad you can't get it until you're over 50 or immunocompromised.
cess11
Why not?
singlow
I think you can if you self pay, but insurance only pays in certain circumstances.
gorfian_robot
good question. but that is how it is in the US and MX.
travisgriggs
Anyone skilled in the medical arts got a dumbed down synopsis of this?
(I just had my first shingles vaccine 2 weeks ago)
jvanderbot
I'm not skilled, but it feels like a validation for the virus theory of dementia
https://med.stanford.edu/news/all-news/2025/03/shingles-vacc...
"The remarkable findings, published April 2 in Nature, support an emerging theory that viruses that affect the nervous system can increase the risk of dementia. If further confirmed, the new findings suggest that a preventive intervention for dementia is already close at hand."
inglor_cz
A lot of things can cause dementia. IIRC, men who use Cialis have a lower risk of dementia, which indicates that better blood flow is beneficial as well.
Our skulls are hard for a reason. Brains are sensitive.
_alternator_
I don’t think that there are many things known to have as strong of an effect as HZ vaccines. The current evidence is that the vaccine eliminates like 20% of all cases, suggesting that HZ (aka chickenpox) is directly responsible for at least 20% of dementia cases, possibly much more.
ortusdux
The original study had a sample size of 10. A follow-up study with n = 13,000 did not find a correlation.
https://www.alzheimers.gov/news/no-association-viagra-and-ci...
shepardrtc
Taking valacyclovir should help prevent or delay as well.
hannob
It looks like the shingles vaccine has positive effects that prevent dementia. (Well, that's in the title.)
This study was possible due to a "natural experiment" where one country gave people from a very specific birth date the vaccine (so people born right before and right after that date were very similar, except for the vaccine).
It's not clear why this is the case. It might be that the virus the vaccine supresses plays a role in dementia development, or it might be that the vaccine causes an immune response that has other indirect positive impacts.
_alternator_
The highlights are a good start. (I’m a doctor, just a nerd who likes to read papers.)
My comments in brackets.
- Herpes zoster vaccination reduced dementia diagnosis in our prior natural experiments. [Previous work. I’m familiar with the Wales experiment where they had a sharp age cutoff for getting the vaccine in their national health system. Comparing those just below and just beyond the cutoff allows for analysis similar to a randomized controlled trial (aka ‘natural experiment’). The results showed a ~20% decrease in dementia due to vaccine, so the results were already pretty strong.]
- Here, we find a lower occurrence of MCI and dementia deaths among dementia patients [MCI = ‘mild cognitive impairment’. This is a more refined result than prior work, harder to see in the data than a clear dementia diagnosis.]
- Herpes zoster vaccination appears to act along the entire clinical course of dementia. [This is not surprising given the earlier results, but the demonstration is harder, and it may lead to recommendations for earlier HZ vaccination, IIRC currently at 50 or 55 in the US.]
- This study’s approach avoids the common confounding concerns of observational data [Basically they are improving their methods and getting stronger results, classic good science.]
hedora
Shingles attacks your nervous system. Avoiding shingles prevents it from damaging your brain, so it isn’t surprising the vaccine reduces dementia.
There are multiple causes for dementia. If I read figure 2 right, the vaccine slightly reduces the chance of mild cognitive impairment, but cuts the chances of dying from dementia by about a third(!)
Also interesting: The vaccine helps at different phases of disease progression.
The simplest explanation is that dementia is due to cumulative damage, not a single event, and that getting shingles is a big hit.
The vaccine probably prevents dementia in the same way staying out of planes makes you invulnerable to parachute failures.
_alternator_
The emerging evidence, taken together, shows a ~20% reduction in dementia over 7 years. So it’s actually pretty dramatic. https://med.stanford.edu/news/all-news/2025/03/shingles-vacc...
wdb
What do they mean with 'dying from dementia'? As typically you don't die from dementia but something like pneumonia or something else. Personally, I wouldn't wish dementia on anyone and definitely wouldn't want to extend my life while having dementia.
jtbayly
A lot of dead BASE jumpers disagree...
busyant
This is probably a key sentence: "...the effect of actually receiving the HZ vaccination was a 3.1 (95% CI: 1.0–6.2, p = 0.007) percentage point reduction in new diagnoses of MCI over 9 years."
MCI = mild cognitive impairment
What's interesting to me is that the effect doesn't appear to be specific to Alzheimer's--rather they see a reduction in all forms of dementia diagnosis.
I suspect the thinking is something along the lines of ... dementia is either caused or heavily influenced by inflammation. Reactivation of HZ virus causes neurological inflammation. So, HZ vaccination is gonna prevent some forms of inflammation and help you avoid dementia--a little bit.
FWIW, I'm trained as a molecular biologist and have a some knowledge of clinical trials, dementia, etc., but I am far from an expert on this.
jibal
Statistics show that in some populations there is less dementia among those who received the shingles vaccine than among those who didn't.
null
this is nice side benefit. but when you hit 50 you want the shingrex (two shots) vax ASAP. you def do NOT want shingles.