Thank you for your comment. And yeah, the protective effect of the shingles vaccine is partly due to the potential of varicella-zoster virus (VZV) to trigger or contribute to neurodegeneration.

There's also some observational evidence that the influenza virus could reduce the risk of dementia as well. But such evidence tend to suffer from healthy vaccinee bias due to the nature of the study design. As far as I know, only the shingles vaccine has conclusive or causal evidence of its anti-dementia effects.

The study by Taquet et al. also showed that both Shingrix and Zostavax were also more protective against dementia than the influenza and tetanus-diphtheria-pertussis vaccines. But I did not discuss them in detail because the distribution of the two other vaccines was not randomized by birth dates.