The recent hype about the shingles vaccines lowering dementia risk got many people thinking, including the prolific Eric Topol (Ground Truths substack), who had written twice on this topic in the last year. 👇
My Mum’s Reinfection Got Me Thinking Again
Not so much about Shingles — which was “solved” by daily Zovirax.
I was thinking if she would benefit from a shingles vaccine — not an antivirus medication, but a vaccine — even after she had recovered.
Even after she has already recovered.
Here’s why.
Vaccines Prevent Dementia 😮
Not an anti-virus medication, but a vaccine.
We already have good data — and a lot of good press in the last year — about using Shingles vaccines off-label to prevent dementia.
The research is showing that the recombinant shingles vaccine — Shingrix — is associated with a significantly lower risk of dementia in older adults.
And that’s not all.
Adult vaccinations, particularly against Herpes Zoster, Influenza, Pneumococcus and Tdap, are associated with a lower risk of dementia.
This pattern is too consistent across too many different vaccines to be noise. Something real is happening.
I went digging into the mechanistic hypotheses to understand why. And I share my learnings below.
Below are two leading hypotheses for why vaccines are able to reduce dementia risk.
[1] Why Vaccines Reduce Dementia Risk: Immune Regulation Hypothesis
Vaccines do not just protect against specific pathogens. They appear to reprogram innate immune cells, making them better at regulating inflammation. This dampens the chronic low-grade inflammatory state that comes with aging.
We know this from mouse models of Alzheimer’s that the vaccine is doing something very useful for the immune regulation of the brain. Microglia — which are the immune cells in the brain — are somehow activated to clear out protein deposits in the brain.
[2] Why Vaccines Reduce Dementia Risk: Antimicrobial Protection Hypothesis
Amyloid beta isn’t just a toxic waste compound.
It can actually be seen as the brain’s way of protecting itself.
Think of it like an antimicrobial that sits in the brain to protect the brain from microbes.
Alzheimer’s disease may be partly what happens when that defense system gets chronically overactivated. This means that the brain needs to keep fending off microbes and ends up creating these protein deposits called amyloid plaques.
So vaccines remove the microbial triggers, the bad guys.
And because the bad guys are removed, the protective system does not need to overwork. And therefore, you end up getting less amyloid plaque protein deposits in the brain —> lowered Alzheimer risk.
And if you remember from a previous article:
Amyloid plaque are trapping lithium
Lithium depletion leads to tau tangles and neuron death
which is the Lithium Hypothesis of Alzheimer’s disease.
Conclusion
Anyway, given the flurry of research emerging in the last year, vaccines can be one of the most accessible underused tools for dementia prevention.
So the question here is, and if you know something about this, please answer. If our parents are in their 60s or 70s and have not had their shingles or recombinant flu vaccine, should they have it, even if you would think they don't need it?
It's definitely worth a conversation. And I wonder what people feel about this.
And if you're in your 40s or 50s, reading this and thinking, that's a future me problem, it's probably not as far away as you think.
Thank you for reading.
