Interestingly, the protective effect was much stronger in women than in men (for men, the effect is statistically insignificant).
Future studies should investigate why!
What did we do?
We used a natural experiment in Wales where shingles vaccine (Zostavax) eligibility was based on an birthdate cutoff, separating eligible and ineligible cohorts. This gave us a great RDD setting to causally estimate its effect on dementia risk.
Why do economists study this?
This was a perfect setting for combining medical data and econometric methods! Policy evaluation of large public health intervention is rarely possible, but here was a unique chance to learn something causal about a vaccine policy at a large scale.
What do we find?
Increase in vaccination uptake at the cutoff:
- 0.01% vaccination for those just too old
- 47.2% vaccination for those just young enough
Receiving the vaccine reduced dementia risk by 3.5 percentage points (95% CI: 0.6 – 7.1, p=0.019), i.e. ~20%, over 7 years.
Our paper on the effect of herpes zoster vaccination on dementia is now out in Nature! 🎉
Huge thanks to Felix Michalik, Seunghun Chung, @pascalge.bsky.social and especially Min Xie (@minxiesci.bsky.social) & Simon Heß (@hesss.org) making the analysis so much fun!
www.nature.com/articles/s41...