Shingles Vaccine & Lower Dementia Risk: What New Study Says

Why in the News?

A new analysis of a vaccination program in Wales found that the shingles vaccine appeared to lower new dementia diagnoses by 20% — more than any other known intervention.

• Shingles is a viral infection causing painful rashes, usually appearing as a stripe of blisters on one side of the torso.
• Causes:
  • It is caused by the varicella-zoster virus, the same virus responsible for chickenpox. After chickenpox, the virus remains dormant and can reactivate as shingles, especially if the immune system is weakened.
  • People who have never had chickenpox can contract the virus through direct contact with shingles blisters or by inhaling virus particles.
  • Pain may persist after the rash disappears. Severe cases can lead to vision loss (if near the eye), facial paralysis, or brain inflammation.
• Prevention: A shingles vaccine, which prevents the reactivation of the varicella-zoster virus, is recommended primarily to individuals over the age of 50 years. It may also be recommended to adults living with a weakened immune system due to conditions such as HIV.

• Wales’ shingles vaccine rollout created a “Natural Experiment,” that closely resembled a randomized control trial. Eligibility was based strictly on age, for minimizing bias.
  • Study began in September 2013 and only those aged 79–80 on that date could get the vaccine that year. Further, the 78-year-olds got it the following year (2014); those over 80 were never eligible. Hence, two similar groups were created that differed only by vaccine eligibility.
• What were the unique findings?
  • Over 7 years, vaccinated individuals had a 3.5% point lower rate of dementia diagnosis.
  • This equals a 20% lower relative risk compared to the unvaccinated group

Conclusion:

Both shingles vaccines (Zostavax and Shingrix) may help reduce dementia risk, with similar protective effects seen in studies. Other common vaccines may also offer some protection against dementia.