Anyone skilled in the medical arts got a dumbed down synopsis of this?
(I just had my first shingles vaccine 2 weeks ago)
(I just had my first shingles vaccine 2 weeks ago)
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."
Our skulls are hard for a reason. Brains are sensitive.
https://www.alzheimers.gov/news/no-association-viagra-and-ci...
But the leading form of dementia is Alzheimer's. Somewhere in the order of 40% of us are expected to get Alzheimer's before we die. The list of things that have been demonstrated to cause Alzheimer's is much, much shorter.
For the last 40 years, the leading theory about Alzheimer's is that it is caused by the beta-amyloid plaques that are found in the brain after death. This theory has produced exactly zero treatments that meaningfully affect clinical symptoms, despite many drug trial and literally billions in research per year. Seriously, between various sources, we've spent something like a quarter of what it cost to put man on the Moon. (It is hard to make a precise comparison, because a lot of that funding was private.)
This single study represents more progress on effective treatments of Alzheimer's than all of that work combined. The importance of the result should not be dismissed.
Top defense.
And WTF is wrong with wearing a Band-Aid? You're criticizing someone for wearing a f**ing Band-Aid!?* Are you nuts?! [pounds desk] Whassamattayou? Can't you stick to the point instead of talking about f**ing Band-Aids?*
https://www.cuimc.columbia.edu/news/antiviral-treatment-fail...
Chickenpox is actually a neurological disease; that's how it re-emerges as shingles later in life. The virus infects nerve cells but (as far as we know) hides out in them without damaging them. Because nerves are critical to bodily function and don't regenerate nearly as efficiently as (for example) skin, liver, or other "sheet tissues" (tissue made of small cells is easier to regenerate; nerves can be as long as a meter and regeneration involves growing a new cell that entire distance), the body has a pile of immunosuppressant signals to prevent killing the nerve while trying to fight an infection. "Hey white blood cells: I know we hate chickenpox, but we hate not being able to swallow more, so maybe lay off the throat nerves, right?"
... but as a result, one doesn't generally purge the chickenpox infection after it occurs. Breakouts into other tissue are swiftly suppressed by our immune systems our whole lives (so swiftly that you don't get symptoms or become contagious), but as we age and the immune system weakens, a breakout can become a full infection and the result is shingles.
... and now, it seems that the "infects nerves without damaging them" hypothesis should be up for question.
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.]
Shingrix had a potential side effect of Guillain-Barre https://en.wikipedia.org/wiki/Guillain–Barré_syndrome#Vaccin...
It's interesting that the linked article references, in different terms, the distinction, obliquely. Zostavax is attentuated; Shingrix recombinant.
"Our findings suggest that live-attenuated HZ vaccination prevents or delays mild cognitive impairment and dementia and slows the disease course among those already living with dementia."
> Recent studies have shown convincingly that vaccines against shingles (Herpes zoster) reduce the risk of dementia. The shingles vaccine now in widespread use (Shingrix) has more of an effect than the previous one (Zostavax). A key difference between these vaccines is that Shingrix contains an ‘adjuvant’, an ingredient designed to enhance the vaccine’s effect. It is therefore possible that the adjuvant contributes to Shingrix’ greater effect than Zostavax on reducing dementia.
Link to study https://www.nature.com/articles/s41541-025-01172-3
I don't know if this study changes the conclusion that Shingrix is more affective than Zostavax.
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.
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.
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.