A natural experiment on the effect of herpes zoster vaccination on dementia

Abstract Neurotropic herpesviruses may be implicated in the development of dementia 1–5 . Moreover, vaccines may have important off-target immunological effects 6–9 . Here we aim to determine the effect of live-attenuated herpes zoster vaccination on the occurrence of dementia diagnoses. To provide causal as opposed to correlational evidence, we take advantage of the fact that, in Wales, eligibility for the zoster vaccine was determined on the basis of an individual’s exact date of birth. Those born before 2 September 1933 were ineligible and remained ineligible for life, whereas those born on or after 2 September 1933 were eligible for at least 1 year to receive the vaccine. Using large-scale electronic…

• WT
  Wu Tsai Neurosciences Institute, Stanford University
• NI
  National Institute of Allergy and Infectious Diseases