A leading Irish geriatrician has called for the addition of the shingles vaccine to the national adult immunisation programme, following the publication of a study showing a 20 per cent reduced risk of developing dementia in older people who received a vaccine for shingles compared to those who didn’t.
“Ireland is one of the few countries in the EU which doesn’t [pay for] the shingles vaccine in older people, which is a significant missed opportunity,” says Professor Seán Kennelly, consultant physician in geriatric medicine at Tallaght University Hospital and clinical associate professor of gerontology at Trinity College Dublin (TCD).
He spoke to The Irish Times following a study into the electronic health records of more than 280,000 older adults in Wales, half of whom received the shingles vaccine while half did not. The research, which was published in the Nature journal last week, found that those who received the vaccine were 20 per cent less likely to develop dementia over the next seven years compared to those who did not receive the vaccine.
The research team, led by Pascal Geldsetzer from Stanford University, looked at other variables such as education levels and rates of common health conditions across both groups but could find no differences, aside from shingles vaccination, that would explain the drop in diagnosis of dementia.
Sally Rooney: ‘I enjoy writing about men ... the dangerous charisma of the oppressor class’
Alzheimer’s: ‘I’ve lost my friend and my companion,’ says Úna Crawford O’Brien of fellow Fair City actor Bryan Murray
Ryan Adams at Vicar Street: A gig that nobody will forget anytime soon, but perhaps not for all the right reasons
“For the first time, we are able to say much more confidently that the shingles vaccine causes a reduction in dementia risk. If this truly is a causal effect, we have a finding of tremendous importance,” Geldsetzer said.
[ ‘I wouldn’t wish it on anyone’: What to know and do about shinglesOpens in new window ]
Overall, the vaccinated group reduced their personal risk of developing dementia by 3.5 per cent. The protective effect was stronger in women than in men.
This latest research is not the first to find a link between shingles vaccine and reduced risk of dementia. When the live shingles vaccine, Zostavax (which was the focus of the Welsh study), was first rolled out in the US in 2006, several studies found lower rates of dementia in people who received the vaccine. Then, in 2024, researchers at the University of Oxford in England found an even stronger protective effect from the DNA-based vaccine, Shingrix. The study authors, led by Maxime Taquet, concluded that these newer vaccines had an even more potent impact on the immune system.
Scientists have already found evidence that illnesses such as influenza, pneumonia and Covid can impact on the buildup of proteins in the body which set off a cascade of events in the brain, leading to cell death and, ultimately, symptoms of dementia.
Prof Kennelly explains: “We’ve known for a long time that different infections predispose people to the risk of dementia as they can act as potential triggers for the accumulation of amyloid protein, the protein linked to Alzheimer’s disease, one of the most common forms of dementia.”
This new study is the cherry on the top of the cake in terms of the reduced dementia risk. It’s a no-brainer when we have an effective vaccine to give it to those over 65 to protect them from getting shingles
— Professor Sean Kennelly
This new study adds to the knowledge that vaccines which prevent these infections from occurring can reduce the risk of dementia. The scientific explanation is that vaccines turn down the immune system response, therefore preventing a spike of inflammation in the body which would otherwise result in the production of these more harmful proteins – the precursors of dementia.
“Studies have found that one influenza vaccine reduces the risk of dementia by 16 per cent, and the influenza vaccine given over four consecutive years reduces the risk of dementia by 40 per cent,” says Prof Kennelly.
Covid, influenza and pneumococcal vaccination are all available free for older adults in Ireland, albeit with different age brackets (over 60 for flu vaccine, over 65 for pneumococcal vaccine and over 70 for Covid booster).
While the National Immunisation Advisory Committee recommends shingles vaccinations for all adults aged 65 and over, a health technology assessment carried out by the Health Information and Quality Authority in 2024 found that at the current vaccine price, adding vaccination to the routine general population aged 50 years and older would not be an efficient use of HSE resources.
Brian Lawlor, geriatric psychiatrist and Professor of Old Age Psychiatry at TCD, says that this new data from the Nature study should be factored into any revised cost-effectiveness evaluation.
“We need more randomised controlled trials evidence to support its definitive benefit regarding lowering dementia risk and the use of a vaccine for dementia risk reduction,” he says.
Meanwhile, Prof Kennelly says that the availability of an effective vaccine against shingles is already a valid case for including it in the national adult immunisation programme.
“I have some patients paying up to €500 for a two-dose shingles vaccine, while most of the people who need it aren’t getting it,” he says.
Shingles is an infection of the nerves and skin, caused by the herpes varicella-zoster virus, the same virus that causes chickenpox. Most people have chickenpox in childhood and the virus remains dormant in the nerve cells throughout your life. If it is reactivated in later life, it causes shingles, the main symptoms of which are pain and an itchy rash. Some people go on to suffer from post-herpetic neuralgia, a severe nerve pain condition which can last for more than three months after the rash has gone. One in three people who previously had chickenpox are likely to get shingles over their lifetime. You cannot pass shingles to another person, but someone who hasn’t had chickenpox can catch it from someone with shingles.
“Shingles is such a debilitating condition and while most people get over it in two weeks, symptoms can persist for up to six months. This new study is the cherry on the top of the cake in terms of the reduced dementia risk. It’s a no-brainer when we have an effective vaccine to give it to those over 65 to protect them from getting shingles,” says Prof Kennelly.
Shingrix is the only shingles vaccine now available in Ireland, following the voluntary withdrawal of an earlier live single dose vaccine, Zostavax, a few years ago. The vaccine, which is administered by GPs and pharmacists by prior appointment, is expected to give protection from shingles for up to four years.
In Ireland, there are about 64,000 people living with dementia, a figure that is projected to rise to 150,000 by 2045 due to our ageing population. However, in spite of these startling statistics, a large body of research focusing on brain health has developed in the last decade or so which points to strong evidence that up to 50 per cent of dementia can be prevented with a combination of factors including better heart health, good nutrition, better social networks and regular vision and hearing checkups.
As a result, some researchers – such as Dr Eleonare Bayen, neurologist at the Sorbonne University in Paris – are educating children on brain health.
Dr Bayen, who was in Dublin in 2024 for Creative Brain Week at TCD, runs My Brain Robbie, a programme that teaches young people the eight protective practices for brain health: be social, be active, be a lifelong learner, have a good diet, avoid smoking and excessive alcohol, mind your health, sleep well and avoid head injuries.
“By improving lifestyle, educational and environmental factors – for example, reducing air pollution – and treating chronic conditions such as diabetes and high blood pressure, the amount of dementia in communities can be reduced by up to 40 per cent,” she told The Irish Times at Creative Brain Week.
