Could the Shingles Vaccine Potentially Have a Protective Effect Against Dementia? According to a study by Dr. Markus Eyting and Dr. Min Xie from Stanford University, evidence suggests that the herpes zoster vaccine could help in preventing dementia. In their study, they replicated the vaccine’s effect of reducing the contraction of shingles by approximately 19.9%, then showed a reduction in the chances of dementia over a seven-year period following vaccination. They also found that the impact was greater in women than in men.