The short answer: the shingles vaccine is linked to a lower risk of dementia, but it has not been proven to prevent it. In a study of 509,926 older adults published in Annals of Internal Medicine in June 2026, people who had at least one dose of Shingrix, the recombinant shingles vaccine, were diagnosed with dementia less often over four years than similar people who were not vaccinated: 18.8% versus 24.6%, a 24% lower relative risk. A second study of about 1.5 million Medicare beneficiaries found a similar pattern. Both are observational, so they show an association, not cause and effect. The vaccine is already recommended to prevent shingles. The dementia findings are a reason to take up the offer if you are eligible, not a reason to seek the jab for brain protection alone.
If you have seen headlines asking whether the shingles jab protects your brain, this is the study behind them. Here is what the researchers actually did, what the numbers mean in plain language, why scientists think a link is plausible, and where the limits are. We also cover who can get the vaccine free on the NHS in 2026 and what to do next if that is you.
What is shingles, and what is the vaccine?
Shingles, also called herpes zoster, is a painful rash caused by the varicella zoster virus. It is the same virus that causes chickenpox. After chickenpox clears, the virus stays quiet in nerve tissue, often for decades. As the immune system weakens with age or illness, the virus can reactivate and travel along a nerve, producing a blistering rash on one side of the body, nerve pain and, for some people, pain that lasts for months after the rash has healed. Doctors call that lingering pain post-herpetic neuralgia. Shingles can also affect the eye and, rarely, lead to more serious complications.
The current vaccine, Shingrix, is a recombinant zoster vaccine. It does not contain live virus. It is given as two doses and contains an adjuvant, a substance that helps the immune system respond more strongly. Shingrix replaced the older live vaccine, Zostavax, which is no longer used in the United States and has been replaced in the UK programme as well. The vaccine is already recommended because shingles itself is common, painful and harder to shake off in later life. The dementia question is newer: could preventing viral reactivation, or the immune response the vaccine triggers, also help the brain?
What did the 509,926-person study find?
The headline study was led by Kaley Hayes and colleagues at Brown University School of Public Health, with collaborators from the University of Delaware, the Providence Veterans Affairs Medical Center and other institutions. It was published in Annals of Internal Medicine in June 2026 and funded by GlaxoSmithKline, which makes Shingrix. The funder had no role in the study design or publication, according to the paper.
The team used Medicare claims linked to electronic health records from PointClickCare Life Sciences, covering more than 5,500 skilled nursing facilities in the United States. They included 509,926 adults aged 66 and older who were admitted between 2017 and 2022, with a mean age of 79. Everyone was free of a dementia diagnosis at the start and was eligible for the vaccine. Only 8,843 people, about 1.7%, received at least one dose of Shingrix within 12 months of admission. Most of those doses were given after discharge.
The analysis used a method called target trial emulation. In plain terms, the researchers set out the rules of a hypothetical randomised trial in advance, then reweighted the observational data to mimic that trial as closely as possible. They accounted for 57 factors that could differ between vaccinated and unvaccinated people. Follow-up lasted up to four years.
The results were clear. Dementia was diagnosed in 18.8% of vaccinated participants and 24.6% of unvaccinated participants over four years. That is an absolute difference of 5.8 percentage points and a relative risk of 0.76, which is a 24% lower relative risk. The authors estimate that this corresponds to about one in every 17 dementia diagnoses potentially being avoided. The association was present but weaker in men and in people who had previously received the older live shingles vaccine.
Those numbers need context. The people in this study were entering skilled nursing facilities, so they were older and less well than the general population, and their four-year dementia rates are higher than you would expect in the community. The 18.8% and 24.6% figures describe this specific, high-risk group. They do not mean that one in four unvaccinated adults in their late seventies will develop dementia in four years.
Does a second, larger study agree?
Yes, broadly. A separate analysis led by Susan dos Reis at the University of Maryland School of Pharmacy was published in Alzheimer’s & Dementia on 28 April 2026. It covered about 1.5 million US Medicare beneficiaries aged 65 and older: 502,845 people who had received both doses of the recombinant vaccine and 1,005,690 matched unvaccinated controls. About 60% of participants were female and 55% were aged 70 to 79.
Over the first three years of follow-up, two-dose vaccination was associated with a 33% lower risk of any dementia, a 28% lower risk of Alzheimer’s disease and a 33% lower risk of vascular dementia. The recorded incidence was 10.45 cases per 1,000 person-years in the vaccinated group and 15.73 per 1,000 person-years in the unvaccinated group. Beyond three years, the association persisted but was smaller: a 26% lower risk of any dementia, 17% lower for Alzheimer’s disease and 34% lower for vascular dementia. The Maryland team adjusted for medical conditions, prescription medicines, health care use and other preventive vaccinations.
Two earlier lines of evidence point in the same direction. A Welsh natural experiment, which used a birth-date eligibility cut-off for the older vaccine, found about a 20% lower dementia risk over seven years. An Oxford study published in Nature Medicine in 2024 compared Shingrix with the older Zostavax vaccine in more than 200,000 people and found at least a 17% lower risk of dementia diagnoses over six years with Shingrix. None of these studies is a randomised trial, but the consistency across populations, vaccines and methods is why researchers are taking the signal seriously.
Why might a shingles vaccine be linked to brain health?
Researchers have ideas, not proof. The most straightforward is that preventing shingles prevents the consequences of reactivation. Each shingles episode brings inflammation, and inflammation around nerves and blood vessels is one of the processes implicated in dementia. Shingles is also associated with a higher risk of stroke in the weeks after an episode, and vascular damage contributes to vascular dementia and can worsen Alzheimer’s disease. Stop the reactivation and you may avoid some of that harm.
A second idea concerns the vaccine itself. Shingrix uses a potent adjuvant system called AS01B, which produces a strong and durable immune response. Some researchers think that this broader immune stimulation, not just the block on viral reactivation, could influence long-term brain health. That would help explain why Shingrix appears at least as protective as the older live vaccine in head-to-head comparisons.
A third possibility is less exciting but important. People who get vaccinated may differ from people who do not in ways that also protect the brain: they may see doctors more often, manage blood pressure and diabetes more closely, or have higher income and education. Statisticians call this healthy vaccinee bias. Good studies try to adjust for it, including by checking whether unrelated vaccines show the same pattern. In the Brown study, the authors ran negative control analyses, which are checks designed to detect leftover bias, and those checks suggested some residual confounding remains. In plain language, part of the gap probably reflects differences between the groups rather than the vaccine itself.
What this evidence does not prove
Three limits matter. First, association is not causation. An observational study, however carefully designed, cannot prove that the vaccine caused the lower dementia rate. Only a randomised trial, where people are assigned by chance to vaccine or control, can do that, and no such trial for dementia prevention has reported yet.
Second, the Brown cohort is specific. Adults entering skilled nursing facilities are not representative of all older adults. They have more illness, more contact with health services and higher baseline dementia risk. The size of any benefit in healthier, community-dwelling adults could be smaller or larger. We do not know.
Third, vaccinated people were a small minority in the Brown study and were, on average, slightly younger and healthier. The researchers adjusted for this, but adjustment is never perfect. The honest summary, which the study authors themselves give, is that the findings are promising and consistent, that they add to a growing body of evidence, and that clinical trials are needed to confirm them. Health authorities, including the NHS, have not changed vaccine policy on dementia grounds. The recommendation remains what it has been: get vaccinated to prevent shingles and its complications.
Who can get the shingles vaccine on the NHS in 2026?
Eligibility in England is age-based, with an additional route for people who are severely immunosuppressed. Scotland, Wales and Northern Ireland run their own programmes with similar rules, so check locally if you live outside England.
- Adults turning 65: if you turn 65 between 1 September 2025 and 31 August 2026, you are eligible from your 65th birthday. This is the first stage of a phased expansion that began in September 2023.
- Adults aged 70 to 79: the catch-up cohort remains eligible until their 80th birthday. If you had your first dose before turning 80, you can still have the second dose up to your 81st birthday.
- Adults aged 18 and over with a severely weakened immune system: you qualify regardless of age. This includes, for example, people who have had an organ or stem cell transplant, people with certain blood cancers, people with advanced or untreated HIV and people on strong immunosuppressive treatment. There is no upper age limit for this group.
If you are under 65, not in the 70 to 79 catch-up group and not severely immunosuppressed, you will not be offered the vaccine on the NHS in 2026. Adults aged 80 and over who have not started the course are also not eligible. Shingrix is a two-dose course. For severely immunosuppressed adults, the second dose is given between eight weeks and six months after the first. For immunocompetent adults, the interval is usually six to 12 months. If you miss the window, you do not need to restart; your GP practice can give the second dose when you next attend. If you have had shingles before, you are still advised to be vaccinated once you have recovered, because shingles can recur. Your GP can advise on timing, and NHS guidance commonly suggests waiting until the rash has fully settled.
Most people have only mild side effects: a sore arm for a day or two, tiredness, headache or muscle aches, most often after the second dose. Symptoms usually settle within two to three days. Severe allergic reactions are very rare. If you are unsure whether you qualify, ask your GP practice rather than assuming. Eligibility turns on your date of birth and, for the immunosuppressed group, on your specific condition and treatment.
Should you get the vaccine because of the dementia findings?
If you are eligible, yes, get it, but for the established reason: shingles is a miserable, sometimes disabling illness, and the vaccine prevents most cases and reduces the risk of long-lasting nerve pain. Think of the dementia data as a possible bonus that strengthens an already good decision, not as the main reason.
If you are not eligible, the evidence does not currently justify paying privately or travelling for the vaccine solely to protect your brain. The studies show associations in older, often less healthy populations, follow-up is only a few years, and we do not yet know whether the effect is causal, how long it lasts, or whether it applies equally to younger or healthier adults. What does have strong evidence for brain health at every age is unglamorous: keeping blood pressure controlled, staying physically active, not smoking, treating hearing loss, sleeping well and staying socially engaged. A conversation with your GP about those, and about any memory concerns, is worth more today than chasing a vaccine outside the programme.
If you are caring for an older relative who is eligible and has not been vaccinated, helping them book both doses is a concrete, useful step. Two appointments, a sore arm, and strong protection against a painful illness, with a promising but unproven possibility of brain benefit on top.
Frequently asked questions
Does the shingles vaccine prevent dementia?
It has not been proven to prevent dementia. Large observational studies, including the 2026 Brown University analysis of 509,926 adults and a Maryland study of about 1.5 million Medicare beneficiaries, associate Shingrix vaccination with a 24% to 33% lower risk of a dementia diagnosis over three to four years. Because these studies did not randomly assign the vaccine, they cannot prove cause and effect. Randomised trials are needed.
How much lower was dementia risk in the 509,926-person study?
Over four years, dementia was diagnosed in 18.8% of vaccinated participants and 24.6% of unvaccinated participants. That is 5.8 percentage points lower in absolute terms and a 24% lower relative risk. The researchers estimate that this is equivalent to about one in 17 dementia diagnoses potentially being avoided. The participants were older adults entering skilled nursing facilities, so these rates are higher than in the general population.
Who is eligible for the free NHS shingles vaccine in 2026?
In England, you are eligible if you are turning 65, if you are aged 70 to 79 and have not completed the course, or if you are 18 or over with a severely weakened immune system. Once eligible, you remain eligible until your 80th birthday. Rules are similar in Scotland, Wales and Northern Ireland. Ask your GP practice if you are unsure.
I have already had shingles. Do I still need the vaccine?
Yes, in most cases. Having shingles once does not guarantee lasting protection and shingles can happen again. Vaccination after recovery reduces the risk of another episode. Wait until the rash has fully healed and speak to your GP about timing.
What are the side effects of Shingrix?
The most common side effects are a sore arm, tiredness, headache and muscle aches, usually lasting one to three days and more noticeable after the second dose. Severe allergic reactions are very rare. Many people plan a quieter day after their appointment as a precaution.
Should I pay privately for the shingles vaccine to protect my brain?
Current evidence does not support paying privately for dementia prevention alone. The findings are observational, follow-up is short and the effect has not been confirmed in randomised trials. If you are eligible on the NHS, take up the free offer for shingles prevention. If you are not eligible, discuss overall brain health and vaccine options with your GP.
Sources
- Hayes K et al. Recombinant zoster vaccine and dementia risk in skilled nursing facility residents. Annals of Internal Medicine. 2026. DOI: 10.7326/ANNALS-25-04689.
- dos Reis S et al. Recombinant zoster vaccine and risk of dementia in Medicare beneficiaries. Alzheimer’s & Dementia. 28 April 2026.
- Taquet M et al. The recombinant shingles vaccine and reduced risk of dementia. Nature Medicine. 2024.
- NHS conditions: shingles vaccine eligibility and programme guidance for England, Scotland, Wales and Northern Ireland, including the UK Health Security Agency Green Book chapter on shingles (herpes zoster).
- Brown University School of Public Health, University of Delaware and Medical News Today summaries of the Annals of Internal Medicine study, including the 509,926-person cohort, 18.8% versus 24.6% four-year dementia diagnoses and the one-in-17 estimate.
This article is for information only and is not medical advice. Vaccine eligibility and timing depend on your age, health and treatment. If you are worried about shingles, memory or dementia risk, speak to a qualified clinician.
