Overview
- The analysis found about a 2 percentage-point decrease or delay in dementia diagnoses over 5.5 years among those eligible for free herpes zoster vaccination.
- Researchers exploited Ontario’s policy making residents who turned 71 on or after January 1, 2017 eligible, enabling comparisons with adjacent birth cohorts just outside eligibility.
- The decline in new cases was concentrated in the 1945–1946 cohorts covered by the program and was not seen at other birthdate thresholds or in provinces without free access.
- The protective signal reached statistical significance in women (p=0.029) but not in men (p=0.52), underscoring sex-specific heterogeneity.
- Related work reports biologically plausible pathways and consistent associations, including USC data linking shingles vaccination to lower inflammation and slower epigenetic aging, while experts urge further studies before policy shifts, with some UK clinicians noting private Shingrix options outside NHS age criteria.