Context: A new study by Wales finds that the Shingles vaccines may reduce the risk of dementia.
Relevance of the Topic : Prelims: Key facts related to shingles; dementia.
About Shingles
- Shingles is a viral infection that causes painful rashes. It is caused by the varicella-zoster virus- the virus which also causes chickenpox.
- Shingles typically produce a painful and blistering rash, erupting in a stripe of blisters that wraps around either the left or right side of the torso, along a nerve path. It can occur anywhere on the body.
- Symptoms: Painful rashes, and in severe cases, vision loss, brain inflammation, or paralysis.
- Transmission:
- Reactivation of the varicella zoster virus. After recovering from chickenpox, the virus remains dormant in the body and can reactivate later in life as shingles.
- The virus could be transmitted if the person comes into direct contact with the blisters of someone with Shingles to develop chickenpox.
- Vaccine: Shingles vaccine prevents this reactivation and is typically recommended for individuals over the age of 50 and those with compromised immunity (e.g., people living with HIV).
Findings of the Recent Study:
- A recent study from Wales has found the potential of the shingles vaccine to reduce the risk of dementia (a major neurodegenerative condition for which there is currently no cure).
- It found dementia diagnoses among people who had gotten the shingles vaccine reduced 3.5% over a seven-year period. This equates to a 20% lower relative risk of getting dementia compared to the unvaccinated population.
How do vaccines prevent dementia?
Scientists are yet to determine what might be behind this but there are two leading theories:
- Viral Reactivation Hypothesis: The varicella-zoster virus, which causes shingles, has been linked to long-term cognitive damage; vaccination may reduce dementia risk by preventing the virus from reactivating.
- Immune Modulation Hypothesis: The vaccine may induce beneficial changes in the immune system that help protect against neurodegenerative processes associated with dementia.
Shingles Vaccines & their Effectiveness:
- There are two approved shingles vaccines- Zostavax and Shingrix, both available in India.
- Zostavax uses a live, weakened virus, while Shingrix uses a recombinant technology to develop parts of the virus that do not cause the disease.
- Both vaccines show promising results in reducing dementia risk, but the recombinant Shingrix is preferred globally due to its stronger and longer-lasting protection, especially in older adults.
These findings suggest that routine adult vaccinations may play a broader neuroprotective role beyond preventing infectious diseases.