Introduction
•Alzheimer’s disease (AD) affects approximately 12% of adults aged ≥65 years, in Puerto Rico (PR).
•Emerging evidence suggests that neuroinflammation and latent viral reactivation may contribute to AD pathogenesis.
•Varicella-zoster virus (VZV), a neurotropic herpesvirus, has been implicated in central nervous system inflammation and vascular injury.
•However, Caribbean Hispanic populations remain underrepresented in this area of research.
•We examined whether VZV vaccination is associated with AD diagnosis and cognitive outcomes in older Puerto Rican adults.
Methods
•Cross-sectional analysis of 91 adults from the Association-Gut-Microbiome-AD cohort.
•Participants were categorized by zoster vaccination status (vaccinated n=43; unvaccinated n=48).
•AD diagnosis was determined from clinical records, and cognitive status was assessed using the MoCA, CDR, and Depression scales
•Group differences were evaluated using chi-square, Fisher’s exact, and t-tests, as appropriate.
Results
•AD was present in 56 participants (61.5%).
•Vaccinated individuals had a significantly lower prevalence of AD compared to unvaccinated individuals (27.9% vs 91.7%, p<0.001), corresponding to markedly reduced odds of AD (OR≈0.04).
•Vaccinated participants also demonstrated less severe cognitive impairment, with lower rates of moderate-to-severe impairment on MoCA (37.2% vs 68.1%, p=0.008) and a higher proportion without dementia on CDR (69.8% vs 12.8%, p<0.001).
•However, vaccinated individuals were younger and had higher educational attainment, and unvaccinated participants exhibited greater cognitive severity and higher use of dementia-related medications, suggesting important baseline differences between groups.
•No significant differences were observed in GDS scores or APOE genotype distribution.
Conclusion
•AD was present in 56 participants (61.5%).
•Vaccinated individuals had a significantly lower prevalence of AD compared to unvaccinated individuals (27.9% vs 91.7%, p<0.001), corresponding to markedly reduced odds of AD (OR≈0.04).
•Vaccinated participants also demonstrated less severe cognitive impairment, with lower rates of moderate-to-severe impairment on MoCA (37.2% vs 68.1%, p=0.008) and a higher proportion without dementia on CDR (69.8% vs 12.8%, p<0.001).
•However, vaccinated individuals were younger and had higher educational attainment, and unvaccinated participants exhibited greater cognitive severity and higher use of dementia-related medications, suggesting important baseline differences between groups.
•No significant differences were observed in GDS scores or APOE genotype distribution.
References:
•Scherrer, J. F., Salas, J., Wiemken, T. L., Jacobs, C., Morley, J. E., & Bucholz, K. K. (2021). Impact of herpes zoster vaccination on incident dementia: A retrospective study in an older adult cohort. Journal of Alzheimer’s Disease, 79(2), 841–855. https://doi.org/10.3233/JAD-201275
•Taquet, M., Dercon, Q., Luciano, S., Geddes, J. R., Husain, M., & Harrison, P. J. (2024). The recombinant shingles vaccine is associated with lower risk of dementia. Nature Medicine, 30(10), 2970–2977. https://doi.org/10.1038/s41591-024-03201-5
•Alzheimer’s Disease Alzheimer’s Association. (2025). 2025 Alzheimer’s disease facts and figures. Alzheimer’s & Dementia, 21(4), e70032. https://doi.org/10.1002/alz.70032
Contact:
Clinical: vanessa.sepulveda@upr.edu
Microbiome: filipa.godoy@upr.edu
Research student: jalexca.pinero@upr.edu
This research was supported by the NIH National Institute of General Medical Sciences under grant U54GM133807 and P20GM103475. IRB APPROVAL NUMBER: 2290033626
