Shingles sufferers like Holly Willoughby can use a treatment that could beat dementia - Daily Mail
Shingles sufferers like Holly Willoughby can use a treatment that could be deployed as a weapon in the war on dementia
- Study finds patients with shingles vaccine 20 per cent less likely to get dementia
- Dementia is country's biggest killer - causing around 66,000 deaths each year
Every hour, about 23 people in the UK are diagnosed with dementia – that's roughly 575 a day, and more than 200,000 a year.
Today, one million Britons are living with the cruel disease which robs sufferers of their memories, along with a raft of other symptoms. And numbers are steadily rising.
Dementia also causes roughly 66,000 deaths a year, making it the country's biggest killer.
And yet, despite the hundreds of millions of pounds pumped into researching it, the causes of most types, and how to prevent or even effectively slow its progress, are still a mystery.
But we could be about to see a dramatic change of approach. Research published last week has caused a stir in the scientific community for suggesting that, in many cases, a common viral infection could be to blame. The study found people given the shingles vaccine are 20 per cent less likely to develop Alzheimer's – the most common form of dementia – than those who don't have the jab.
Shingles is an infection of a nerve caused by a virus in the herpes family – the same one that causes chickenpox. Once the virus is contracted it stays in the body for life, and it's believed that about 95 per cent of the population carry it. It has been thought that it lies dormant, only causing problems occasionally. But could it silently be causing havoc, gradually damaging the brain and ultimately leading to dementia?
Mysterious virus that hit Holly Willoughby - and is carried by almost all of us
Shingles – the painful rash caused by the varicella-zoster virus – may be more common in older age but it also affects young people. Earlier this year, This Morning host Holly Willoughby, 42, had to take time off from the ITV show after developing the illness.
The vast majority of people in the UK contract varicella-zoster as a child, when it causes chickenpox. While the immune system kicks in to resolve the initial infection, the virus remains in the body, lying dormant in the spinal cord.
Occasionally in adulthood, when the immune system becomes compromised, it can reactivate and cause shingles. Older people have naturally weaker immunity, but stress, other illnesses and medical treatments are all triggers that bring on shingles.
The shingles virus, however, is not the only infection which can linger in the body and cause major illnesses in later life.
Epstein-Barr virus is found in nine out of ten adults. It is usually picked up as a child when it can lead to glandular fever, a severe cold-like illness, and then remains dormant in the throat and blood cells. Until recently, scientists believed that Epstein-Barr had little impact on the body after the initial illness. But last year a study concluded it can trigger multiple sclerosis – an incurable disease which develops when the immune system attacks the myelin sheath, which coats the brain and spinal-cord nerves.
The two common herpes viruses – known as herpes one and herpes two – also remain in the body for life. Herpes one triggers cold sores on the lips, whereas herpes two leads to genital blisters.
Human papillomavirus (HPV) is passed on through skin-to-skin contact and is found in about four out of five people in the UK. In most cases, the immune system clears it from the body, but some types can develop into cervical cancer.
Experts say the theory holds weight. And, if it is true, the findings would mean that a vaccine which is already available to every person in the UK over the age of 70 could help reduce the risk of the dreaded, incurable disease. It could even lead to the development of a vaccine for Alzheimer's that could be given early on in life.
Professor Adam Finn, a vaccine expert at the University of Bristol, says: 'As a virus researcher I never expected to be studying dementia, but it is possible that a big chunk of dementia cases are caused by viral infections. If that's the case, we could create vaccines that stop some forms of dementia happening in the first place.'
There are a number of types of herpes virus. These include varicella-zoster, which causes chickenpox, and the slightly less common herpes simplex virus, which cause cold sores on the lips and blisters on the genitals. Although these viruses stay in the body, they cause problems only infrequently.
It's thought that when the immune system, which normally keeps them in check, becomes weakened, it gives them the opportunity to reactivate.
When the dormant varicella-zoster reactivates, it causes shingles – a painful rash of sores. Although it can strike at almost any age, older people, who have naturally weaker immune systems, are most vulnerable.
For this reason, since 2013 the NHS has offered all over-70s a shingles vaccine. This jab, which contains a live, weakened varicella-zoster virus, isn't a cure. It works by training the immune system to recognise and attack the virus as soon as it becomes active, reducing the risk of shingles by about 50 per cent.
In the latest study, researchers at Stanford University in the US found a clear link between the shingles vaccine and dementia by taking advantage of an aspect of the vaccination programme in Wales.
When NHS Wales began to offer the shingles jab, it strictly disqualified anyone who was 80 or older on the day the campaign began. This decision was based on research which shows the shingles vaccine is most effective when given before the age of 80.
It meant the researchers were able to compare the dementia rates in the unvaccinated population who had only just missed out on the jab, due to their age, with the heavily vaccinated population of a very similar age who were eligible.
This data from about 280,000 people gave a clear picture of the impact that taking a shingles vaccine had on the risk of dementia occurring.
'The only difference between these two large groups of people is that one half were eligible for the vaccine and the other half were not,' says Professor Pascal Geldsetzer, global health expert at Stanford University.
It revealed that people who received the shingles jab were, on average, 20 per cent less likely to get all forms of dementia, including Alzheimer's and vascular dementia – the second most common type. The vaccine appears far stronger in women than men, reducing their risk by about 30 per cent. The reduction for men was about ten per cent.
It is important to point out the study is what is called a 'pre-print' – it has not yet been published in a scientific journal nor forensically scrutinised by other scientists in a process known as peer review.
But researchers involved believe their findings could lead to further revelations about the causes of dementia and how to prevent it.
'There is a clear need for future research,' says Prof Geldsetzer. 'The next step should be looking at whether giving the vaccine at a younger age reduces the rates of dementia further.
'We also want to see what happens if booster shots of the vaccine are given, too.'
Leading scientists who have analysed the data believe the findings are significant. 'This is truly exciting research, found using a very smart method,' says Professor Peter Openshaw, an immunologist at Imperial College London. 'It offers not only a potential explanation for some cases of dementia, but a preventative vaccine that reduces the risk of this terrible disease. It also opens up the possibility of looking at what other viruses are linked to dementia, as it's unlikely to be just this one.
'It's important that we see this data replicated in a different patient population to double-check it. But if we can do that, we may look back at this piece of research in a few years' time as a very significant milestone.'
For the past 40 years, researchers have considered that Alzheimer's is triggered by toxic proteins which build up in the brain, called amyloid plaque. However, new and expensive drugs designed to target these proteins have had limited success at slowing the disease, while also sparking severe, life-threatening side effects.
A growing number of brain experts now argue that the amyloid theory may be too simplistic, and that perhaps the proteins are a symptom of another problem which begins developing years earlier, rather than the cause.
The new findings may indicate that, as people age, varicella-zoster can make its way to the brain where it damages sensitive tissue.
A similar phenomenon is seen in multiple sclerosis, the incurable neurological condition that leads to poor mobility, numbness, fatigue and paralysis.
Last year a study concluded that the condition – which affects 130,000 people in the UK – is caused by the Epstein-Barr virus, the same infection that causes glandular fever.
'It's possible that viruses such as varicella-zoster may be connected to dementia, in the same way Epstein-Barr is to multiple sclerosis,' says Prof Finn.
However, not all scientists are convinced.
One dementia researcher, who asked to remain anonymous, critiqued the Stanford University researchers for choosing to go public with the study before it had been peer reviewed.
'It's irritating that the authors should puff it up like this without the usual processes,' he says.
The same expert also questions the validity of their findings due to the fact that the effect of the vaccine was much more pronounced in women, adding 'The results will probably turn out to be an anomaly – the unbalanced effect in women makes it implausible.'
But the researchers involved in the study strongly disagree.
They argue that the difference in dementia rates between women and men is representative of the fact that Alzheimer's affects women differently to men.
Studies show that women are twice as likely to get Alzheimer's as men and are also more likely to have heavy deposits of amyloid in their brains.
Scientists believe this may be linked to differences in the male and female immune systems which, studies show, means women are much more likely to get immune system diseases. Although the reasons for this are still unclear, women are, for example, four times more likely to develop multiple sclerosis.
Experts also argue that future studies of the effect of the shingles vaccine on dementia could show an even stronger response as a new jab has been developed which is far more effective than the one given to the Welsh patients.
In the Zostavax trial, it was shown the jab is only about 50 per cent effective at preventing the return of shingles. Another vaccine, Shingrix, has been shown to be 90 per cent effective.
Last year, The Mail on Sunday revealed that the NHS plans to begin offering Shringrix to all over-70s.
'If it turns out that the reason the jab is reducing rates of dementia is because it is tackling the varicella-zoster virus, then Shringrix would work even better because it's a far superior vaccine,' explains Prof Finn.
Researchers have stressed that this issue, along with many others, has not been resolved by the study.
'We don't know why the shingles vaccine reduces the risk of dementia,' says Prof Geldsetzer. 'It could be something about how the vaccine impacts the body, rather than the virus itself. All we can say is that more research in this field is needed.'
One other intriguing theory is that the effect is not triggered by protecting the brain from the virus, but by the boost to the immune system that a vaccination of any sort creates.
'The human body has immune cells which naturally clear amyloid plaque from the brain, but as we age, these cells dwindle and amyloid begins to build up,' says Professor Rudolph Tanzi, a neurologist at Harvard University. 'That's when we begin to see Alzheimer's.
'We know that when people get vaccinated, it gives the whole immune system a boost, so it's possible that getting vaccinated for any virus, not just shingles, could increase the presence of these cells in the brain and clear the plaque before it causes damage.
'All the expensive Alzheimer's drugs have been designed to tackle the disease once it is diagnosed, but what if the way to prevent it was to regularly take a drug that keeps plaque away, in the same way that statins reduce cholesterol?
'This research may show that simply boosting the immune system using a generic vaccine could be a cheaper, simpler and safer alternative to anti-amyloid drugs.'
More research to confirm the role other viruses play in Alzheimer's could soon be on the way. An ongoing trial in the US is looking at whether an anti-viral drug which tackles herpes simplex, called valacyclovir, could slow the progression of Alzheimer's in patients who are in the early stages of the disease. The trial is expected to be completed by early next year.
'A number of companies are looking to test out the impact of their herpes vaccines on dementia,' says Prof Finn. 'This new evidence will mean pharmaceutical firms that develop shingles vaccines will want to do the same as well.'
Experts say that any vaccine that is proven in trials to reduce the risk of dementia would revolutionise the treatment of the disease.
'Companies have spent billions and billions on these anti-amyloid drugs and don't have a lot to show for them,' says Prof Openshaw. 'If vaccines could be used to slow the development of dementia then they would be far easier to roll out than these expensive, complicated drugs which people have to take for the rest of their lives. The answer could be as simple as a jab.'
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