I’ve always been very open about being a big fan of vaccines. Not because of politics or blind faith, but because the evidence – accumulated over decades – overwhelmingly shows their benefits.
Vaccines are among the most effective medical interventions ever devised for reducing risks of infection.
Smallpox was eradicated entirely – and polio has been driven to the brink of extinction – through vaccination. And cases of cervical cancer, which is caused by a viral infection (human papillomavirus, or HPV), have fallen sharply following vaccination programmes (whatever the vaccine sceptics may claim).
And now the science is showing that some vaccines have other, unexpected but important benefits – potentially reducing the risk of dementia as well as improving our lifespan and healthspan (years of healthy living).
The most impressive results come from the shingles vaccine.
This protects against the varicella- zoster virus, which causes chickenpox in childhood and can lie dormant for years only to be reactivated later in life (when immunity wanes, for instance, or as a result of stress), causing shingles.
Before the shingles vaccine was introduced by the NHS in 2013 (that first vaccine, Zostavax, has since been replaced by the more effective Shingrix), I used to treat lots of older patients with it.
They’d come to A&E with severe pain, blistering rashes and complications including blindness (as the virus attacked the nerves around the eyes).
Thankfully, this type of patient is becoming less common thanks to the introduction of the shingles vaccines.
But over the past few years, something remarkable has emerged from the data on patients who’d been vaccinated.
The first hints came from large observational studies, in which researchers followed millions of older adults over time, and compared rates of dementia. Again and again, they noticed that people vaccinated against shingles appeared less likely to develop it.
Larger, better-designed studies, including a major review last year published in the journal Age and Ageing, which pooled data from more than 100million adults aged over 50, have found a consistent association between vaccines – particularly shingles, flu and pneumococcal – and a lower risk of dementia.
But the most fascinating paper of all was published last month in The Journals of Gerontology, as it offered an explanation for how the vaccination could reduce dementia risk.
Researchers at the University of Southern California in the US analysed blood samples and health data from nearly 4,000 adults over the age of 70 – and found those vaccinated against shingles had lower levels of chronic inflammation, one of the key biological drivers of ageing (and dementia).
They also appeared to be ageing more slowly at a molecular level: their ‘epigenetic clocks’, a way of estimating biological age based on chemical changes that build up in our DNA, were ticking more slowly than those of their unvaccinated peers. In simple terms, cells of vaccinated individuals looked biologically younger.
This matters because it offers a plausible mechanism.
Shingles is caused by the reactivation of varicella-zoster virus: the theory is that the immune system has to keep that virus permanently under control and that, over years, this causes immune strain and chronic inflammation that slowly damages blood vessels, nerves and brain tissue.
This isn’t proof, but it does offer a biologically plausible explanation for why vaccinated people appear to age more slowly and are less likely to develop dementia.
A similar idea has been proposed for other vaccines, such as the flu jab, where preventing repeated infections is thought to reduce the cumulative inflammatory ‘wear and tear’ on the body over time.
So what does this mean for you? In the UK, the NHS offers the shingles vaccine for adults turning 65, 70 to 79-year-olds, and people with a severely weakened immune system.
That decision was made because that is when the vaccine is most cost-effective in preventing shingles and its complications. But if you are outside the age groups offered it on the NHS, that does not mean the vaccine doesn’t work for you.
It means that with limited resources, the NHS has to prioritise where it gets the biggest return. And its recommendations are not necessarily what is best for you as an individual.
So if you can afford it and are aged over 80 and not had the vaccine, I would strongly recommend getting it privately; two injections are needed six months apart and each injection costs about £240.
And if you’re under 65? The vaccine is licensed for people from the age 50, which means it is proven to be safe and effective at that age and you could have it privately.
For most healthy people, waiting until the age when the NHS offers it is reasonable. But for over-50s at higher risk, including people with immune conditions or on immunosuppressant drugs, it’s worth the investment.
I’m in this higher-risk category myself. I’m mildly immunosuppressed, due to Crohn’s disease – so when I turn 50, I’m very likely to pay to get Shingrix privately.
It may also be something you want to consider if you have a family history of dementia or other reasons to be particularly concerned about brain health, such as genetic risk factors.
There are no obvious long-term risks to having the shingles jab. The main side-effects are short-lived; a sore arm, tiredness or flu-like symptoms for a day or so.
And if you’ve had shingles in the past, previous infection will not provide you with reliable protection, and vaccination reduces the risk of recurrence and serious complications.
At the moment the vaccine is a one-off course, not because repeat doses are unsafe, but because we don’t yet have the long-term data to tell us if re-vaccination is a good idea. What we also don’t know yet is whether having the vaccine earlier in life – in your 50s and 60s, say – and then again later, confers additional benefit compared with having it just once.
But my take-home from all of this is simple.
Longevity is not just about avoiding ultra-processed food and taking exercise, important as those are. It is also about using good science and modern technology to reduce future harm.
The shingles vaccine already reduces suffering, hospital admissions and long-term nerve pain. That alone is reason enough to recommend it.
The emerging evidence that it may also protect the ageing brain makes it one of the most interesting longevity interventions we currently have.
Follow Dr Rob at @drrobgalloway
