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 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.

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 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.

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...