“The remarkable findings support an emerging theory that viruses that affect the nervous system can increase the risk of dementia.”
Wales created an accidental experiment when it made shingles vaccine eligibility dependent on exact birthdate, with those born before September 2, 1933 permanently ineligible. Analyzing health records showed vaccinated individuals were 20% less likely to develop dementia over seven years. A follow-up study found the vaccine may also slow progression in those already diagnosed, with only 30% of vaccinated dementia patients dying from the disease compared to nearly half of unvaccinated patients. The effect was more pronounced in women.