> Most of the evidence of its anti-dementia effect relates to an earlier version of the vaccine, which used a weakened form of the live virus. It has since been

> Most of the evidence of its anti-dementia effect relates to an earlier version of the vaccine, which used a weakened form of the live virus. It has since been largely replaced by a new one, Shingrix, which contains just a sprinkling of proteins from the virus and is seen as safer because it cannot cause an infection. Unfortunately the apparent anti-dementia effect of this old vaccine (Zostavax) recently turned out to be a statistical illusion: https://youtube.com/watch?v=qlTnnQytOJ0 https://youtube.com/watch?v=qlTnnQytOJ0 It is not clear whether the effect from Shingrix (the new one) is real or not. We currently don't have a case-control study which could prove causation.