Shingles Vaccine Linked to 20% Dementia Risk Reduction in Landmark Study

A study published in Nature used a natural experiment in Wales to provide the strongest evidence yet of a causal relationship between shingles vaccination and lower dementia risk, prompting calls for further research.

The study tracked over 280,000 older adults in Wales over seven years, finding that those vaccinated with the Zostavax shingles vaccine had a 20% lower risk of developing dementia compared to unvaccinated individuals.
Researchers leveraged a unique 2013 Welsh vaccination policy with an age-based eligibility cutoff, creating a natural experiment that closely mimics a randomized controlled trial.
The protective effect was more pronounced in women, potentially due to stronger immune responses to vaccination, though the underlying mechanisms remain unclear.
The study builds on evidence linking the varicella-zoster virus to neuroinflammation and dementia, suggesting that vaccination may prevent reactivation of the virus or confer broader immune benefits.
While the study used the discontinued Zostavax vaccine, researchers are advocating for trials to confirm these findings and evaluate the newer, more effective Shingrix vaccine for similar or enhanced benefits.