No Established Cardiovascular Benefit, But Strong Evidence for Dementia Risk Reduction
The recombinant zoster vaccine (Shingrix) does NOT have proven cardiovascular benefits, but is strongly associated with a significant reduction in dementia risk—approximately 29-32% reduction based on the most recent evidence.
Cardiovascular Outcomes
The evidence regarding cardiovascular benefit is limited and negative:
A 2025 real-world study specifically examining patients with immune-mediated inflammatory diseases on JAK inhibitors found no significant reduction in major adverse cardiovascular events (MACE) with RZV vaccination (HR 1.121,95% CI: 0.901-1.395) 1.
The FDA label for Shingrix 2 and current guidelines [3-3] make no mention of cardiovascular benefits as an indication or outcome.
While the vaccine did show a 39% reduction in all-cause mortality in the JAK inhibitor population (HR 0.610,95% CI: 0.427-0.870), this was not specifically attributed to cardiovascular mechanisms 1.
Bottom line on CV benefit: There is no evidence supporting cardiovascular protection from Shingrix vaccination.
Dementia Risk Reduction
The evidence for dementia benefit is robust and compelling:
Strongest Recent Evidence
A 2025 meta-analysis of cohort studies including over 14 million participants found that HZ vaccination reduced dementia risk by 29% (HR = 0.71,95% CI: 0.66-0.76) 4. This represents the highest-quality synthesis of available evidence.
Key Supporting Studies
Recombinant vaccine specifically: A 2025 retrospective cohort of 4.5 million individuals demonstrated that full RZV vaccination (2 doses) was associated with a 32% reduction in dementia risk (HR 0.68,95% CI: 0.67-0.70), with partial vaccination (1 dose) showing 11% reduction (HR 0.89,95% CI: 0.87-0.92) 5.
Dose-response relationship: The fully vaccinated group had an incidence rate of 99.1 cases per 10,000 person-years compared to 135.0 in unvaccinated individuals—translating to 164 additional days lived without dementia diagnosis 5.
Comparative effectiveness: A 2024 Nature Medicine study showed RZV was associated with 17% increase in diagnosis-free time and demonstrated superiority over influenza and tetanus-diphtheria-pertussis vaccines for dementia protection 6.
Clinical Implications by Patient Subgroup
Women benefit more than men: The protective effect is consistently greater in females across multiple studies 6, 1.
Age matters: Protection is particularly pronounced in adults ≥65 years, with mortality benefits most evident in this age group (HR 0.500,95% CI: 0.301-0.806) 1.
Prior herpes zoster is a risk factor: Having a zoster diagnosis before vaccination was associated with 47% increased dementia hazard (HR 1.47,95% CI: 1.42-1.52), emphasizing the importance of vaccination before infection occurs 5.
Proposed Mechanisms
The dementia protection likely operates through multiple pathways 7:
- Prevention of chronic neuroinflammation from VZV reactivation
- Reduction of infection-related cerebrovascular lesions
- Activation of "trained immunity" responses
- Anti-inflammatory response modulation
Important Caveats
- Most evidence comes from observational studies, not randomized controlled trials
- The effect appears to attenuate over time, being strongest 1-2 years post-vaccination and persisting up to 6 years 8
- Antiviral treatment for active zoster infection also showed protective effects (HR 0.42,95% CI: 0.40-0.44), suggesting that preventing or treating VZV reactivation is key 5
Clinical Recommendation
Given the substantial dementia risk reduction without cardiovascular benefit, Shingrix should be recommended to eligible adults ≥50 years primarily for herpes zoster prevention, with the significant additional benefit of potential dementia risk reduction—particularly in women and those ≥65 years. The vaccine should ideally be administered before any herpes zoster infection occurs to maximize both benefits.