Shingles Vaccination May Reduce Dementia

With an aging population, age-related cognitive decline is an increasing health burden for families and society. Recently, there has been scientific evidence indicating that herpesviruses may influence the risk of cognitive decline, such as dementia.

A recent study published in Alzheimer's Research & Therapy revealed that individuals who have had herpes zoster (HZ, shingles) may have a 20% higher risk of experiencing subsequent subjective cognitive decline (SCD) over the long term.

This large-scale study is the first to explore the connection between shingles and the risk of subjective cognitive decline. However, this link between the shingles virus and cognition is not fully understood.

These researchers wrote on August 12, 2023, that evidence on the longitudinal association between shingles and cognitive decline is conflicting, and whether the risk differs by the APOE ε4-carrier gene status has not been studied.

To investigate this association, Brigham and Women's Hospital researchers examined survey data from 149,327 individuals.

Compared with individuals with no history of shingles, the multivariable-adjusted relative risk (MVRR) (95% CI) of a 3-unit increment in SCD score was significantly and independently higher among individuals with a history of HZ.

Still, the duration of time since HZ, when the elevated risk of SCD was statistically significant, differed among the study cohorts.

Among the subset of women with information on HZ vaccination, there was a suggestion that the long-term risk of SCD may be greater among women who were not vaccinated against HZ.

The study also found that men with shingles who carry the APOE4 gene, a known risk factor for dementia, had an even higher risk of subjective cognitive decline. About 25% of people carry one copy of APOE4, and 3% may carry two copies. 

These researchers noted that this increased risk was observed in men but not women.

Previous research has yielded mixed evidence on the link between shingles and dementia, possibly because some studies only included individuals who sought medical attention for them using insurance claims or administrative diagnostic data, wrote these researchers.

Regarding herpes zoster prevention, there are various shingles vaccines available globally.

In the United States, GSK's Shingrix®, a non-live, adjuvanted recombinant shingles vaccine, is offered by clinics and most pharmacies. Furthermore numerous health insurance programs cover most of the cost related to vaccination.