Your anti-ageing stack should include this vaccine

The shingles vaccine seems to reduce the risk of dementia. There is speculation that it might slow down ageing

We live in a strange world where longevity influencers with millions of followers will tell you to drink a blue liquid, sit in a hyperbaric chamber or plunge into freezing water to add a few years to your life. The evidence is often a small study, some long-lived rats or a guess. Yet one intervention backed by natural experiments across four countries shows a 20% cut in dementia risk, yet it remains largely invisible in longevity boosterism. It is a vaccine. For shingles.

This discovery came not from a lab but a set of bureaucratic accidents. Four countries–Australia, Canada, Wales and the US–each rolled out shingles vaccines with hard eligibility cutoffs. If you were born after a certain date you didn’t qualify. Researchers then realised that they had a natural experiment: if you compare people born just before and after those lines you can isolate the vaccine’s effects. The findings are really important and suggest it may cut dementia risk by 20%.

The evidence: In Wales, people who received the live attenuated shingles vaccine (Zostavax) were 3.5 percentage points less likely to be diagnosed with dementia over seven years–roughly a 20% relative reduction. Similar patterns have been found in Australia and Canada. The US study on the newer vaccine Shingrix found a 17% increase in diagnosis-free time. Four countries, two vaccines but the same basic message. For a comprehensive analysis see Eric Topol’s post on Ground Truths.

Women seemed to gain even more protection than men (although men still benefit¹). Why? Nobody knows. And the mechanism behind this observation remains a mystery. One theory is that the vaccine may tamp down chronic inflammation or block repeated viral flare ups that are damaging neurons. Or it may be something else altogether.

Does it slow disease progression? We don’t know. In the Welsh study the vaccine seems to avert one in 20 deaths–in other words it affects your probability of dying from dementia. Some outlets are framing this as slowing the progression of dementia while you have it but we don’t actually know this is the case. A reduction in the risk of death could well come from slowing the disease but equally it could come from preventing complications or providing other health benefits.

What about this talk about slowing biological ageing? There is growing interest in whether some adult vaccines (shingles, influenza and pneumococcal) might be associated with reduced risks of age-related diseases. A new observational study in the Journal of Gerontology looks at a single set of blood samples taken in 2016. They found vaccinated individuals had lower scores of inflammation and epigenetic ageing markers, and a lower composite biological ageing score. This is pure observational data so there are all the usual caveats about causation not being known.

What this means right now: Imagine you are 50, or approaching this age, and watching a parent decline with Alzheimer’s. You know that their pathology probably started around the age you are now². Unless you live in America you will not be offered a shot until you are 65³, if at all. Now you need to decide if you want to pay around £150 to £240 ($200 to $325) per shot. You will need two. That is the dilemma.

The irony is that we live in an age of biohacking, longevity stacks and of blue goo and unproven ageing biomarkers, while one of the most robust findings in gerontology–a vaccine that may protect the ageing brain–is out of reach for hundreds of millions. The deeper irony is America is the epicentre of a longevity craze, the shingles vaccine is recommended from 50 for shingles AND is mostly free but two-thirds⁴ do not get it. If the 20% risk reduction holds over a lifetime that is very roughly a million preventable cases⁵ of dementia walking around unprotected.

We shouldn’t be surprised. Vaccinations have always been a longevity technology. But more than just saving life outright, we also know that having severe diseases like measles or covid also has aging effects on the body and as mentioned previously there is growing interest in whether adult-vaccines might reduce the risk of age-related diseases. Not that you are likely to hear this pro-vaccine messaging from America’s health secretary. RFK Jr is busy dosing with odd blue liquids, taking testosterone, fasting, and taking “a ton of vitamins and nutrients”. Meanwhile the intervention with the best evidence sits quietly in your doctor’s fridge.

1. A 2025 study in South Korea suggests men get stronger cardiovascular benefits–with a 23% relative risk reduction in these events.

2. Alzheimer’s begins 20 years or more before memory loss and other symptoms

3. Australia offers it at 65 or older, UK is moving to 60 (over ten years!)

4. Tom Frienden in the comments

5. Check my back of the envelope maths! There are currently 7.2m Americans over the age of 65 who are living with dementia. Assume that two-thirds are unvaccinated and that they were all to have been vaccinated to obtain 20% fewer cases that would be about a million preventable cases.