Neurocognitive Decline Series - Immunizations - which ones are best for lifespan, healthspan and neurocognition?

1. Tetanus / Diphtheria Booster (Td or Tdap)

Dear Members,
When we think of vaccines, most of us picture protection from infectious agents such as tetanus, pneumonia, or the flu. But emerging evidence suggests vaccines may do far more: they appear to train the immune system in ways that lower the risk of dementia, Parkinson’s disease, and premature death.

Below is an overview of key adult immunizations shown to support longevity and brain health, along with highlights from recent studies.

• Recommended every 10 years for all adults (We recommend having these every 4 years, preferably with the version that also covers pertussis the Tdap).
• Recent studies suggest tetanus/diphtheria vaccination is linked to lower risk of both dementia and Parkinson’s disease.
• A large U.S. Veterans Affairs study found individuals who had received a recent Td/Tdap booster were significantly less likely to develop dementia than those unvaccinated (Liu et al., J Alzheimers Dis, 2022).
• Another analysis found those vaccinated within the past five years had an 83% lower odds of Parkinson’s disease onset compared to those without a recent booster.
• Possible mechanism: immune “training” reduces chronic inflammation—a major driver of neurodegeneration.

2. Respiratory Syncytial Virus (RSV) Vaccine

• Approved in 2023 for adults over age 60 or those at high risk ages 50-59 years (Arexvy® and Abrysvo®).  This is currently a one time vaccine, but likely will need boosters.
• RSV infection in older adults often leads to hospitalization, severe respiratory illness, and cardiovascular complications.
• In the pivotal New England Journal of Medicine trial, the RSV vaccine reduced severe infection risk and hospitalization by ~83% (Walsh et al., 2023).
• While long-term data on dementia or Parkinson’s prevention are not yet available, preventing severe systemic infections helps protect vascular and brain health indirectly.
  

3. Influenza Vaccine (Annual Flu Shot)

• Annual influenza vaccination remains one of the simplest, best-studied tools for longevity.
• Multiple studies have shown that people who consistently get flu shots have lower mortality rates and better cardiovascular outcomes.
• In a nationwide study of over 2 million older adults, flu vaccination was associated with a 40% reduced risk of Alzheimer’s disease (Bukhbinder et al., Alzheimers Dement, 2022).
• Another study found that flu-vaccinated individuals had a reduced risk of Parkinson’s disease (Lee et al., Mov Disord, 2020).
  

4. Pneumococcal Vaccine (Pneumovax 23 or PCV20)

• Protects against pneumonia and invasive pneumococcal disease, which can accelerate cognitive decline.
• A landmark cohort study found pneumococcal vaccination between ages 65–75 was associated with a 25–30% reduction in Alzheimer’s disease risk (Verreault et al., CMAJ, 2001).
• Combined flu and pneumococcal vaccination appears to have additive brain-protective effects (Wiemken et al., J Am Geriatr Soc, 2021).
• Mechanistically, preventing systemic infection reduces neuroinflammation and vascular injury—both implicated in dementia progression.
  

5. Shingles Vaccine (Shingrix®)

• Recommended for adults over 50.
• Reactivation of the varicella-zoster virus (which causes shingles) is linked with increased risk of stroke, dementia, and Parkinson’s disease.  It is noted that less VZV reactivation can reduce reactivation of latent HSV-1 which is a risk, especially for those with an ApoE4.  These 2 viruses can trigger each other.
• A 2021 JAMA Network Open study of more than 2 million adults found those vaccinated against shingles had a 20% lower risk of developing dementia (Scherrer et al., 2021).
• Preventing shingles also reduces chronic inflammation and nerve damage—contributors to long-term cognitive decline.

Key Takeaways for Longevity-Oriented Patients

• Vaccines not only prevent infections but may also protect the aging brain by reducing inflammation, vascular injury, and immune dysregulation.
• The strongest evidence supports influenza, pneumococcal, and shingles vaccines, with promising data emerging for tetanus boosters.
• RSV vaccination is new but likely contributes indirectly by preventing severe respiratory and cardiac complications.
• Staying current on adult immunizations is a low-risk, high-value intervention to extend both lifespan and healthspan.
• One can generally self-schedule these at pharmacies like CVS, Walgreens, Publix and others without a doctor’s order or visit.
  

Selected References

• Bukhbinder, A. S., et al. Alzheimers Dement. 2022 — Influenza vaccination and incident Alzheimer’s disease.
• Wiemken, T. L., et al. J Am Geriatr Soc. 2021 — Influenza and pneumococcal vaccination associated with reduced Alzheimer’s incidence.
• Liu, H., et al. J Alzheimers Dis. 2022 — Tetanus/diphtheria vaccination and risk of dementia.
• Lee, C. Y., et al. Mov Disord. 2020 — Influenza vaccination reduces Parkinson’s disease risk.
• Verreault, R., et al. CMAJ. 2001 — Pneumococcal vaccination and reduced Alzheimer’s risk.
• Scherrer, J. F., et al. JAMA Netw Open. 2021 — Shingles vaccination and dementia risk.
• Walsh, E. E., et al. N Engl J Med. 2023 — RSV vaccine efficacy in older adults.
  

Bottom Line

Vaccination isn’t just about avoiding illness—it’s a longevity intervention. By reducing infection-driven inflammation and supporting immune resilience, these vaccines help protect your brain, body, and years of healthy living.

If you’re unsure whether your immunizations are up to date, please discuss your vaccination plan at your next visit.

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