Shingles vaccine update

Shingles vaccination is in the news again.

Shingles vaccine update

ou may remember the newsletter article shared in April 2025, outlining two studies that had seen a correlation between the Shingles vaccine and lowered dementia risk: Shingles vaccination and dementia risk. Now more studies have emerged further strengthening this evidence.

Published in The Lancet, Herpes zoster vaccination and incident dementia in Canada: an analysis of natural experiments, further examined whether the live herpes zoster vaccine affects the likelihood of receiving a dementia diagnosis among older adults. The research team drew on two natural experiments created by Ontario’s age‑based eligibility rules for publicly funded herpes zoster vaccination. The included cohort differed only slightly in age, and therefore were not expected to differ meaningfully in health status or behaviour, making them well‑suited for assessing causal effects of vaccine eligibility.

The researchers found that being born before or after the vaccine eligibility dates had a measurable impact on dementia incidence.

Another study, The effect of shingles vaccination at different stages of the dementia disease course, has also found that the herpes zoster vaccine acts across all stages of dementia. Findings suggested lower mild-cognitive impairment diagnoses and dementia deaths across the vaccinated population.

This new research strengthens growing evidence that shingles vaccination may have meaningful, long‑term cognitive benefits. Because the findings arise from natural experiments rather than traditional observational studies, they provide more confidence that the effect is real, not the product of lifestyle differences between people who choose vaccination and those who do not.