The findings, published in the journal Nature, suggest that protecting against the reactivation of the chickenpox virus—which causes shingles—could be a promising new approach in tackling the global dementia crisis. Dementia currently affects more than 57 million people worldwide, and projections show this number could triple by 2050, reaching over 150 million.
While age, genetics, and vascular diseases have long been known as risk factors, growing evidence points to viral infections as another contributor—especially those that affect the nervous system, such as shingles.
Shingles is caused by the varicella zoster virus, which lies dormant in nerve tissue after a person has recovered from chickenpox. The virus can reactivate later in life, triggering painful rashes and nerve complications.
Now, scientists believe it may also play a role in the development of dementia. To investigate this connection, researchers took advantage of a unique public health policy introduced in Wales on September 1, 2013, which offered the shingles vaccine to all individuals turning 79 years old. Those born just one week before this date were not eligible, allowing researchers to compare two nearly identical age groups—one vaccinated and one not. The seven-year study followed nearly 300,000 individuals.
It found that those who received the shingles vaccine had a 37.2% lower risk of developing shingles. More significantly, they were also 3.5% less likely to be diagnosed with dementia—a relative risk reduction of 20%. “This new study adds to our current knowledge by suggesting the shingles vaccine may also reduce someone’s risk of developing dementia,” said Dr. Courtney Kloske, Director of Scientific Engagement at the Alzheimer’s Association, who was not involved in the research. She emphasized that while the findings are promising, more studies are needed across diverse populations.
Dr. Pascal Geldsetzer, senior author of the study, described the setup as a “natural randomized trial,” where two similar populations—divided only by a health policy cutoff date—allowed for robust comparisons in real-world conditions. Interestingly, the dementia risk reduction appeared more pronounced in women than in men, despite both genders showing similar decreases in shingles and related nerve pain. Experts suggest that this may be due to stronger immune responses typically observed in women, or the higher incidence of shingles among women, which may amplify the vaccine’s benefits.
Dr. Steven Allder, a consultant neurologist at Re:Cognition Health, noted that if these findings are confirmed, shingles vaccination could become a compelling public health strategy, especially considering the rising economic and social costs of dementia care. “A relatively inexpensive vaccine could prove to be a cost-effective preventive measure,” he said.
In the United States, the CDC currently recommends the Shingrix vaccine—a more effective, recombinant version—for adults over 50, and for immunocompromised individuals over 19. Shingrix, which replaces the older live-attenuated Zostavax vaccine used in the study, is over 90% effective at preventing shingles and is generally well tolerated. While the results are exciting, experts urge caution.
Some unanswered questions remain, such as whether the reduced dementia risk stems directly from the vaccine or from the lower incidence of shingles. Additionally, the study focused on the older Zostavax vaccine, which is no longer used in the U.S., raising the question of whether the current Shingrix vaccine provides the same neuroprotective benefit.
Still, the research offers a glimmer of hope in the fight against dementia. If future studies confirm the protective effect of shingles vaccination, it could transform how public health systems approach dementia prevention—offering a relatively simple and low-cost intervention with far-reaching potential. Reply Reply all Forward Add reaction
