What is the association between Shingrix (zoster vaccine recombinant) vaccination and the risk of dementia?

From the Guidelines

There is currently no established link between the Shingrix vaccination and a reduced risk for dementia, and adults should not receive this vaccine specifically for dementia prevention. Shingrix is a recombinant zoster vaccine approved for the prevention of shingles (herpes zoster) in adults aged 50 and older, with a vaccine efficacy of 97.2% in the ZOE-50 trial and 89.8% in the ZOE-70 trial 1. While some research has explored potential connections between certain infections, inflammation, and dementia risk, there is insufficient evidence specifically connecting Shingrix vaccination to dementia prevention. The primary benefit of Shingrix vaccination is the prevention of shingles and its complications, such as postherpetic neuralgia, with a pooled analysis of participants 70 years of age or older from the ZOE-50 and ZOE-70 trials demonstrating a vaccine efficacy of 91.3% against HZ and 88.8% against PHN 1.

Some key points to consider about Shingrix vaccination include:

• The vaccine is administered in two doses, 2-6 months apart, and is over 90% effective at preventing shingles 1
• The persistence of protection conferred by RZV was maintained above 83.3% for up to 8 years, and decreased to 73% at 10 years 1
• Safety data from the ZOE-50 and ZOE-70 trials showed that there was no difference between the vaccinated and placebo groups in the incidence of SAEs and deaths, however, the vaccinated group had a significantly higher incidence of grade 3 injection site reactions and systemic symptoms compared to the placebo group 1
• The adjuvanted vaccine, RZV, was associated with a significantly higher rate of injection-site and systemic reactions compared to ZVL; however, there were no differences in SAEs between RZV and ZVL 1

It is essential to consult with your healthcare provider about appropriate vaccinations based on your age and health status, as getting recommended vaccines like Shingrix is important for overall health in older adults. However, this should not be done with the expectation of preventing dementia, as this is not an established benefit.

From the Research

Shingrix Vaccination and Risk for Dementia

• The relationship between Shingrix vaccination and the risk for dementia has been studied in several research papers 2, 3, 4, 5, 6.
• A study published in medRxiv in 2023 found that receiving the herpes zoster vaccine reduced the probability of a new dementia diagnosis over a follow-up period of seven years by 3.5 percentage points, corresponding to a 19.9% relative reduction in the occurrence of dementia 2.
• Another study published in PloS one in 2021 found that HZ vaccination was associated with lower risk for incident dementia, with a hazard ratio of 0.69 (95% CI: 0.67-0.72) in the VHA cohort and 0.65 (95% CI: 0.57-0.74) in the MarketScan cohort 4.
• A study published in the Annals of family medicine in 2022 found that HZ vaccination was associated with a 31-35% reduced risk of dementia among patients ≥65 years of age 5.
• A quasi-randomized study published in medRxiv in 2024 found that HZ vaccination reduced the incidence of new diagnoses of mild cognitive impairment and deaths due to dementia among individuals living with dementia 6.

Key Findings

• The studies suggest that Shingrix vaccination may be associated with a reduced risk of dementia 2, 4, 5, 6.
• The protective effects of HZ vaccination for dementia were found to be larger among women than men 2, 6.
• The studies used different methodologies, including natural experiments and quasi-randomized designs, to estimate the effect of HZ vaccination on dementia risk 2, 6.

Study Limitations

• The studies had different limitations, including potential confounding variables and selection bias 3, 4, 5.
• The studies used different datasets and populations, which may limit the generalizability of the findings 2, 3, 4, 5, 6.