The effect of shingles vaccination at different stages of the dementia disease course

Volume 188, Issue 25, 11 December 2025, Pages 7049-7064.e20 Article The effect of shingles vaccination at different stages of the dementia disease course Author links open overlay panel , , , , https://doi.org/10.1016/j.cell.2025.11.007 Get rights and content Under a Creative Commons license Open access Highlights • Herpes zoster vaccination reduced dementia diagnosis in our prior natural experiments • Here, we find a lower occurrence of MCI and dementia deaths among dementia patients • Herpes zoster vaccination appears to act along the entire clinical course of dementia • This study’s approach avoids the common confounding concerns of observational data Summary Using natural experiments, we have previously reported that live-attenuated herpes zoster (HZ) vaccination appears to have prevented or delayed dementia diagnoses in both Wales and Australia. Here, we find that HZ vaccination also reduces mild cognitive impairment diagnoses and, among patients living with dementia, deaths due to dementia. Exploratory analyses suggest that the effects are not driven by a specific dementia type. Our approach takes advantage of the fact that individuals who had their eightieth birthday just after the start date of the HZ vaccination program in Wales were eligible for the vaccine for 1 year, whereas those who had their eightieth birthday just before were ineligible and remained ineligible for life. The key strength of our natural experiments is that these comparison groups should be similar in all characteristics except for a minute difference in age. Our findings suggest that live-attenuated HZ vaccination prevents or delays mild cognitive impairment and dementia and slows the disease course among those already living with dementia. Graphical abstract Download: Download high-res image (268KB) Download: Download full-size image Keywords herpes zostervaccinationimmunizationdementiaAlzheimer’s diseasemild cognitive impairmentnatural experimentquasi-experimentvaricella zoster virus 9 Lead contact © 2025 The Author(s). Published by Elsevier Inc.