Shingrix: A New Hope Against Dementia

A few days ago, I wrote about the importance and effectiveness of the Shingrix vaccine in preventing shingles, which in some cases can be a very debilitating painful illness and is highly prevalent in Israel.

Investigating the Impact on Dementia Risk

Curious about how this vaccine might influence dementia risk, Maxime Taquet at the University of Oxford and his colleagues conducted a comprehensive study. They collected medical records of 103,837 individuals in the US who were immunized after the launch of Shingrix in November 2017 and another 103,837 who were immunized before that date.

Key Findings

The researchers then selected 100,532 people in each group, with an average age of 71, who had received a shingles vaccine during each period. They excluded anyone who had received both types of vaccines. The analysis revealed that individuals immunized after November 2017 were 17 percent less likely to develop dementia over the next six years compared to those vaccinated earlier. Although the study did not extend beyond six years due to a reduced number of participants, the initial findings are promising.

Gender-Specific Benefits

Interestingly, women appear to benefit more from the newer vaccine, despite both sexes experiencing similar rates of shingles.

Unraveling the Reasons

The exact reasons for the reduced dementia risk are still unclear. One hypothesis is that herpes zoster infections might contribute to dementia, and a vaccine that more effectively protects against the virus could also better prevent dementia. Taquet suggests this could be a plausible explanation.

The Study’s Robustness

Pascal Geldsetzer at Stanford University in California praises the study for its thoroughness, even though it relies on medical records that do not include other crucial information such as physical activities and diets. He notes that people who lead healthier lifestyles, which may reduce dementia risk, might have waited for the more effective Shingrix vaccine.

Broader Implications

Richard Lathe at the University of Edinburgh in the UK highlights that various vaccines are associated with reduced dementia rates. For instance, the Bacillus Calmette-Guérin (BCG) vaccine, which protects against tuberculosis and can treat bladder cancer, has been linked to a 45 percent reduced dementia risk. Lathe suggests that the benefits might be due to vaccines providing a general immune boost rather than specific protection from shingles.

Conclusion

The Shingrix vaccine’s potential to reduce dementia risk is an exciting development. While further research is needed to fully understand the mechanisms, these findings underscore the broader benefits of vaccination. As we continue to explore the connections between vaccines and cognitive health, the importance of immunization remains clear.

References

1. Original Study:
   • Taquet, M., et al. (2023). “Association of Shingrix Vaccination with Reduced Dementia Risk: A Retrospective Cohort Study.” Nature Medicine. DOI: 10.1038/s41591-024-03201-5
2. New Scientist Article:
   • Lesté-Lasserre, C. (2024). “Evidence mounts that shingles vaccines protect against dementia.” New Scientist