Herpes zoster linked to faster cognitive decline in older adults

Older adults who develop herpes zoster — the reactivation of the varicella-zoster virus commonly known as shingles — show faster decline in global cognitive performance afterward, according to a new longitudinal cohort study published in Aging Clinical and Experimental Research. The study, released as open access on 12 October 2026, followed 16,324 older adults who at their individual baseline had no self-reported shingles, no physician-diagnosed dementia, and no severe cognitive impairment. Over up to 12 years of cognitive follow-up, 3,516 participants developed shingles, allowing the researchers to model the infection as a time-varying exposure in mixed-effects statistical models.

The headline result concerned the annual trajectory of a 27-point global cognitive score. Incident shingles was associated with an additional annual decline of 0.06 points on that scale (beta = −0.06; 95% confidence interval −0.08 to −0.05; p < 0.001). The association did not appear to be driven merely by subtle pre-existing illness around the time of diagnosis: when assessments within two years of the shingles event were excluded, the estimated annual decline was, if anything, larger (beta = −0.09; 95% confidence interval −0.12 to −0.07; p < 0.001).

The team also examined clinically meaningful decline, defined as a drop of three points or more on the global cognitive score. In Cox models adjusted for confounders, shingles was associated with a higher risk of such decline (adjusted hazard ratio 1.09; 95% confidence interval 1.04 to 1.15; p < 0.001). By contrast, the adjusted association between incident shingles and a diagnosis of dementia itself was not statistically significant (hazard ratio 1.12; 95% confidence interval 0.92 to 1.35; p = 0.265). In other words, the measurable speeding-up of cognitive decline in the population was not accompanied, in this cohort, by a statistically detectable increase in dementia incidence.

Because the study was framed around psychosocial vulnerability, the researchers also ran secondary and explicitly exploratory analyses on depressive symptoms and sleep burden. Exploratory statistical decompositions testing whether these factors mediated the association yielded nonsignificant results for depressive symptoms (p = 0.144) and for sleep burden (p = 0.515). However, exploratory subgroup analyses identified statistical interactions with both baseline depressive symptoms (p < 0.001) and baseline sleep burden (p = 0.041), with the association between shingles and cognitive decline appearing stronger at higher baseline levels of each. The authors interpret these analyses cautiously: mediation was not supported, but baseline psychosocial burden may modify who is most affected.

The study has several important limitations that should temper interpretation. It is an observational cohort, so the association between shingles and faster cognitive decline does not establish causation, and residual confounding by health status, inflammation, vaccination history, or access to care cannot be excluded. The exposure was based on self-reported shingles, and the cognitive measure is a global composite rather than domain-specific testing. The dementia analysis was also underpowered to detect modest effects, as the wide confidence interval around the non-significant hazard ratio shows. Finally, the results were shared early as a peer-reviewed accepted manuscript that remains subject to further editing before the final Version of Record.

Subject of Research: Longitudinal association between incident herpes zoster and cognitive decline in older adults

Article Title: Incident herpes zoster and accelerated decline in global cognitive performance among older adults: longitudinal trajectories and psychosocial vulnerability

Article References: Qiu, Y., Song, Z., Zhang, R., Wang, Z., & Wang, H. (2026). Incident herpes zoster and accelerated decline in global cognitive performance among older adults: longitudinal trajectories and psychosocial vulnerability. Aging Clinical and Experimental Research. https://doi.org/10.1007/s40520-026-03529-7

Image Credits: AI Generated

DOI: 10.1007/s40520-026-03529-7

Keywords: herpes zoster, shingles, cognitive decline, older adults, cohort study, dementia, depressive symptoms, sleep burden, longitudinal analysis, global cognitive score, Incident, herpes