A shingles shot may do more than prevent rash — it could help shield the aging brain from dementia, according to a landmark study using real-world data from the UK.
A routine vaccine could offer more than protection from varicella-zoster virus — it could help delay or prevent dementia, according to a robust natural experiment conducted by Stanford researchers and published in the journal Nature. In a recent study, a research team at Stanford University reported that the herpes zoster (shingles) vaccine may lower the risk of developing dementia, offering a potential new tool in the fight against cognitive decline.
Link between herpesviruses and dementia
For years, scientists have explored potential links between neurotropic herpesviruses and dementia. Some evidence suggests that infections caused by these viruses may contribute to neurodegeneration. While vaccination is commonly used to prevent infections, emerging research indicates that vaccines, especially live-attenuated ones, can have broader effects on the immune system, sometimes influencing conditions unrelated to the targeted disease.
However, previous studies examining the relationship between vaccines and dementia have struggled with a key challenge — distinguishing correlation from causation. Many have simply compared dementia rates between vaccinated and unvaccinated individuals, but this approach is prone to bias. Furthermore, factors such as personal health awareness, access to healthcare, and even cognitive ability can influence whether someone gets vaccinated, making it difficult to isolate the true effect of the vaccine.
About the study
In the present study, the researchers utilized the vaccine eligibility rules in Wales, United Kingdom (U.K.), to evaluate the impact of the herpes zoster vaccine on dementia risk. In the U.K., the eligibility for the herpes zoster vaccine was determined solely by birth date. Those born on or after September 2, 1933, were eligible to receive the vaccine, while those born just before this date were not.
This provided the researchers with a unique opportunity to study the vaccine’s effect on dementia risk, as individuals born just a few weeks apart are unlikely to differ in any meaningful way in other aspects of life, except for their access to the vaccine. This rare policy feature enabled researchers to apply a regression discontinuity design, simulating a natural experiment that is highly resistant to confounding. The authors also confirmed their findings using a difference-in-differences instrumental variable (DID-IV) approach, further reinforcing the robustness of their causal claims.
By analyzing large-scale electronic health records, the researchers could compare the long-term dementia risk between these two groups while minimizing confounding factors. The findings were corroborated in a secondary analysis of dementia-related deaths across England and Wales, further strengthening the causal inference. The study used regression discontinuity design, a statistical technique for determining causal relationships, and analyzed data from a seven-year follow-up period.
Major findings
The study found that receiving the herpes zoster vaccine was associated with a 3.5 percentage point reduction in dementia diagnoses over seven years, which translates to a 20% relative decrease. This estimate accounts for the fact that not all individuals who were eligible actually received the vaccine. The protective effect was stronger in women, reaching statistical significance, while the findings in men were inconclusive due to wider confidence intervals.
To confirm their findings, the researchers conducted a separate analysis using death certificate data. This secondary analysis supported their initial conclusions, showing that eligibility for the herpes zoster vaccine reduced dementia-related deaths by approximately 5% over nine years.
Beyond dementia, the study also confirmed that the vaccine significantly reduced the occurrence of shingles, consistent with clinical trial data. However, the observed reduction in dementia risk could not be fully explained by a decrease in shingles cases alone, suggesting that other mechanisms might be at play. Notably, the reduction in dementia incidence only became evident more than one year post-vaccination, supporting theories of long-term immune modulation.
The researchers explored several potential explanations for the vaccine’s apparent protective effect. One hypothesis was that the vaccine helps suppress reactivations of the varicella-zoster virus, which causes shingles. Some studies have suggested that such viral reactivations may contribute to neuroinflammation, a key factor in dementia development.
Another potential mechanism suggested a broader immune-modulating effect of the vaccine. Live-attenuated vaccines, like the herpes zoster vaccine, can stimulate the immune system in ways that extend beyond their primary target. This immune boost may help the body combat other infections or neuroinflammatory processes linked to dementia, potentially via mechanisms such as trained immunity or heterologous adaptive immunity. The study also explored how prior influenza vaccination and autoimmune conditions may modify the vaccine’s effect, supporting the hypothesis that broader immune modulation could contribute to dementia protection.
While these findings are compelling, the researchers acknowledged several limitations. One challenge was the potential under-detection of dementia in health records, as not all cases are formally diagnosed. The study also focused on a specific age group, making it difficult to apply the results to younger populations.
Another important consideration was that the study examined only the live-attenuated herpes zoster vaccine. Importantly, the study focused on the live-attenuated vaccine Zostavax, as the recombinant vaccine Shingrix was introduced only after the study period ended. It is unclear whether the newer vaccine would have the same effects on dementia risk.
Implications and conclusions
Dementia remains one of the most pressing public health challenges worldwide, with no cure currently available. If further research confirms that vaccines can reduce the risk of dementia, this could open up new avenues for prevention. If validated in other settings, the shingles vaccine could represent one of the most effective and cost-effective preventive strategies for dementia. Furthermore, given the widespread availability and safety profile of the herpes zoster vaccine, these findings suggest a promising, low-risk intervention that could potentially help millions of people.
While further research is needed to understand the exact mechanisms at play, this study provides compelling evidence that the herpes zoster vaccine may do more than just prevent shingles — it may also help protect the aging brain.
- Eyting, M., Xie, M., Michalik, F. et al. (2025). A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. DOI:10.1038/s41586-025-08800-x https://www.nature.com/articles/s41586-025-08800-x
News
Scientists Tested an 8-Hour Eating Window and Found a Surprising Brain Benefit
Limiting the daily eating window may provide brain benefits beyond those associated with weight loss. Eating within a shorter daily window may provide cognitive benefits beyond those associated with weight loss alone, according to [...]
Focused Ultrasound Opens Blood-Brain Barrier to Treat Brain Cancer
Summary: A new study demonstrates that primary brain tumors (gliomas) are particularly receptive to targeted drug delivery using focused ultrasound (FUS) combined with microbubbles. The team developed a high-resolution MRI protocol to track blood-brain barrier [...]
AI’s promise and practical limits in drug discovery
AI tools are becoming increasingly common in early drug discovery, allowing scientists to analyse data and navigate large volumes of research. However, according to Dr Raminderpal Singh, turning that potential into consistent scientific workflows [...]
GHCE Concept
From the preface of the book Global Health Care Equivalency in the Age of Nanotechnology, Nanomedicine and Artificial Intelligence, Edited by Frank Boehm: Since the publication of my first book (Nanomedical Device and Systems [...]
Healthcare Headlines: Challenges and Advances in 2026
Health-related updates reveal financial adjustments by Universal Health Services due to Medicaid reimbursement uncertainties, significant pollution-linked health concerns from French-British oil firm Perenco in Congo, drug trial setbacks, potential restructuring at major medical firms, [...]
Scientists Discover the Brain Protein That Helps Alzheimer’s Spread Through the Brain
Scientists have identified a brain protein that may help Alzheimer’s spread, revealing a potential new target for slowing the disease’s progression. Alzheimer’s disease is closely linked to the accumulation of a toxic form of the protein [...]
How Immune Dysregulation Contributes to Psychiatric Disorders
Introduction Growing evidence suggests that disruptions in immune function may play an important role in the development and progression of psychiatric disorders. However, immune mechanisms probably contribute more strongly in some patients than others, [...]
Electrostatic Discharge Boosts Triboelectric Nanogenerator Current and Enables DC Output
Controlled electrical discharges could enable triboelectric nanogenerators to achieve higher peak currents, extending nano-enabled energy harvesting into chemical processing and self-powered sensing. Paper: Electrostatic discharge as a breakthrough strategy for triboelectric nanogenerators. A new review [...]
Swiss laboratory uses old drugs against rare diseases
Researchers at the University of Geneva are combing through collections of approved drugs to find new therapies for rare diseases – with some success. This approach is gaining traction around the world, while pharmaceutical [...]
Nanozyme Aptasensors Show Promise for Faster Food, Health, and Environmental Testing
By pairing robust artificial enzymes with highly selective aptamers, nanozyme aptasensors could help detect disease biomarkers, pathogens, and contaminants faster, but the review shows that real-world deployment still depends on overcoming matrix interference, biofouling, [...]
Paralyzed Man Feels Sensation Again With Brain Stimulation Device
Aneuroprosthetic system has allowed a man with paralysis to grasp and lift objects and feel touch again. The device helped 42-year-old Keith Thomas of Massapequa, New York, who was paralyzed from the chest down [...]
Global Cancer Cases Could Surge 67% by 2050, New Report Warns
New data reveal major geographic disparities and highlight the urgent need for global action on prevention, early detection, and equitable access to treatment. For roughly one in five people worldwide, cancer will become part [...]
A Deadly Ebola-Like Virus Is Spreading. Are We Ready?
BU virologist Nancy Sullivan says the Bundibugyo outbreak in the Democratic Republic of the Congo underscores the need for broader outbreak preparedness. The death of a nurse marked the moment health officials recognized that [...]
Why Most Animal Viruses Never Become Human Pandemics
From receptor mismatch to risky human-animal interfaces, this article explains why spillover is common but true pandemic emergence remains rare. Introduction Humans are constantly exposed to animal viruses through farming, wildlife contact, and the [...]
Stem cell organoids repair heart microvessels in coronary artery disease models
A Stanford University team has shown that vascular organoids derived from human stem cells can repair the heart’s microvessel network in pigs with ischaemic heart disease – a proof-of-concept advancement that could open new therapeutic [...]
Goodbye GP waiting rooms, hello prevention at home
Prevention is suddenly everywhere in NHS reform. The recent £340m community pharmacy deal is moving more services onto the high street. Community Diagnostic Centres are being expanded, and the Neighbourhood Health Framework sets out [...]
