Newsletter Monday
Hello Reader,
Something rather interesting is happening out there.
According to yesterday’s Guardian, demand for private shingles vaccinations is soaring.
And it’s got very little to do with shingles itself.
Instead, it’s the result of emerging research suggesting the vaccine might also reduce the risk of dementia.
People (who aren’t eligible for NHS vaccination) are prepared to pay around £450 for the privilege.
Firstly, I’m delighted to see some positive publicity around vaccines. They’ve done an extraordinary amount for public health and have had a rather rough time in recent years. It’s refreshing to see people actively seeking one out.
Secondly, this is genuinely exciting research.
Discovering that a vaccine developed for one purpose might have an entirely unexpected benefit is fascinating.
But there’s a rather important word in that sentence.
Might.
And we seem to be moving rather quickly from might prevent dementia to here’s my credit card.
A particularly interesting study published in Nature last year took advantage of an unusual situation in Wales.
When the shingles vaccination programme was introduced in England and Wales in 2013, eligibility depended on people’s date of birth.
I remember this rollout very well, mainly because the eligibility rules were so convoluted that, despite having to explain them to patients, I was never entirely sure I understood them myself.
The practice nurses seemed to have it worked out, thankfully.
Patients would ask why their husband could have the vaccine but they couldn’t, despite being practically the same age. I recall there was something about turning 70 or 79 before September, and once you reached 80 you were out of luck.
It all seemed unnecessarily complicated at the time.
Well, I’m delighted to now discover that all that confusion has finally turned out to be useful for something.
Because those peculiar eligibility rules gave researchers an unusual opportunity to compare people who were otherwise very similar but fell on opposite sides of the vaccination cutoff.
It’s a novel way of reducing the bias that often creeps into studies of preventative healthcare.
The researchers estimated that vaccination reduced the probability of receiving a dementia diagnosis over seven years by approximately 20%.
Now that sounds impressive.
But that’s a relative reduction, and percentages have a habit of making things sound more dramatic than they are.
In absolute terms, the estimated difference was 3.5 percentage points.
Roughly three or four fewer dementia diagnoses per 100 people vaccinated over seven years.
Still, potentially very worthwhile.
But the statistical uncertainty was considerable, and this wasn’t a randomised controlled trial. Other studies have produced encouraging findings, although the results aren’t entirely consistent.
So we have a promising discovery, not definitive proof.
Another study, this time comparing two different shingles vaccines, estimated that people receiving the newer vaccine lived an additional 164 days without a dementia diagnosis.
This might sound great.
But does that mean 164 additional days without dementia, or simply 164 days without someone writing it in their medical records?
Because those aren’t necessarily the same thing.
When does dementia start?
Dementia doesn’t generally announce its arrival with a date and time like a heart attack or stroke might do.
As a GP, I’ve seen people brought in by concerned relatives at the first suggestion of memory problems.
I’ve also seen people living with significant cognitive decline for years before receiving a formal diagnosis.
Now, working as a medical examiner, I regularly review records where dementia appears to have been diagnosed only a year or two before death, despite a history suggesting it had been present for considerably longer.
Others die with dementia that was never formally diagnosed or recorded.
We also know that the biological changes associated with Alzheimer’s disease can begin many years before symptoms develop.
So measuring the time until diagnosis isn’t quite the same as measuring when dementia begins.
That doesn’t invalidate the research. But it does matter when we’re interpreting what those impressive percentages actually mean.
And I genuinely hope this turns out to be one of medicine’s happy accidents.
Take sildenafil, for example. You may know it as Viagra.
Originally investigated for cardiovascular conditions, researchers noticed it was having a rather more interesting effect elsewhere.
That one really hit the jackpot for the pharmaceutical company.
Cha-ching💰
Sometimes medicine discovers something useful when it wasn’t looking for it.
But there’s a difference between noticing an unexpected benefit and proving that it exists.
And we’re not quite at the second stage yet.
Dementia frightens people, understandably.
If you’ve watched someone you love deteriorate over several years, I can entirely understand why £450 might seem a small price to pay for the possibility of avoiding the same fate.
And the vaccine itself isn’t a gimmick.
It already offers excellent protection against shingles. So this isn’t snake oil.
But we’re now seeing people pay privately for an additional benefit that hasn’t yet been established.
Those who can afford it can act on the emerging research. Those who can’t must wait.
And I suspect many of those reaching for their credit cards are already doing plenty to look after their health.
The health optimisers.
There’s always one more thing to do. One more test, one more supplement, one more intervention that might tip the odds in our favour.
The difficulty is knowing when doing more actually achieves more.
Meanwhile, we already have some rather good evidence that looking after our cardiovascular and metabolic health matters enormously to dementia risk.
Managing blood pressure, reducing diabetes risk, staying physically active, eating reasonably well and not smoking are all evidence-based ways to protect our long-term health, including our brains.
None guarantees we won’t develop dementia.
But the benefits extend well beyond dementia prevention.
Unfortunately, they require rather more effort than rolling up a sleeve and handing over a credit card.
If I were eligible for shingles vaccination through the NHS, absolutely I’d have it. Shingles is thoroughly unpleasant, and the vaccine is very effective at preventing it.
Would I spend £450 specifically because I believed it would prevent dementia?
Not yet.
I genuinely hope the ongoing research confirms a protective effect. It would be wonderful news.
But promising evidence isn’t proof, and the distinction matters.
We seem increasingly enthusiastic about prevention when it comes in something we can purchase, swallow or inject.
The rather less exciting business of looking after ourselves, day after day, doesn’t attract quite the same attention.
And unlike a vaccine, nobody can sell you that in a convenient two-dose package.
Lynette
