1. The herpes zoster vaccine was associated with a 20% lower risk of developing dementia in older adults over 7 years. 
2. The study used a regression discontinuity design to evaluate dementia incidence among eligible adults.
3. Findings were consistent across sensitivity analyses, including varying the bandwidth around the cutoff, applying different grace periods, and using alternative dementia definitions such as the initiation of dementia-specific pharmacotherapy.
4. "If these findings are truly causal, the zoster vaccine will be both far more effective as well as cost-effective in preventing or delaying dementia," noted investigators.
5. The research called for further investigation into the biological mechanisms underlying the observed effects. 

Source: Nature