Main Finding
A large-scale study in Wales, UK found that the shingles (herpes zoster) vaccine:
Reduced the risk of new dementia diagnoses by ~20% over 7 years.
Suggests the vaccine could be a cost-effective strategy to prevent or delay dementia.
Scientific Context
Herpes virus infections (e.g., shingles) have been linked to:
Increased risk of dementia, including Alzheimer’s disease.
Raises the possibility that vaccination may have protective effects against cognitive decline.
Study Design Highlights
Led by Pascal Geldsetzer (Stanford University) and team.
Used a unique vaccination policy in Wales:
People born on or after 2 Sept 1933 were eligible for shingles vaccine from 1 Sept 2013.
Those born just before this date were not eligible, despite being only weeks older.
This allowed researchers to compare nearly identical populations (age difference of just weeks), minimizing bias.
Cohort and Method
Population studied: 2,82,541 individuals born between 1 Sept 1925 – 1 Sept 1942.
Data source: Electronic health records.
Vaccine uptake:
0.01% in those ineligible (just one week too old).
47.2% in eligible population (just one week younger).
Outcome measured: New dementia diagnoses over 7 years.
Key Observations
20% reduction in dementia diagnosis among the vaccinated.
The protective effect was more significant in women than in men.
The design strongly minimized systematic differences and selection bias between groups.
Caveats and Future Directions
The study is observational, not a randomized controlled trial (RCT).
Causality not yet confirmed – further research and RCTs are needed.
Understanding how the vaccine might protect against dementia remains an open question.
COMMENTS