Dementia Risk After Recombinant Herpes Zoster Vaccination in Older Adults With a Recent Skilled-Nursing Facility Stay

Abstract

BACKGROUND: Observational studies report a protective association between herpes zoster (HZ) vaccination and dementia, but they have methodological limitations or examined a live attenuated vaccine no longer available in the United States. OBJECTIVE: Among older adults recently admitted to a skilled-nursing facility for postacute or long-term care, to estimate the association between dementia and receipt of the recombinant HZ vaccine (RZV) within 12 months of entering the facility or after discharge. DESIGN: The researchers conducted a cohort study using target trial emulation and the clone-censor-weight approach. Participants were followed for up to 4 years until the outcome of dementia, Medicare disenrollment, or death. Inverse probability of clone-censoring weights were applied to pooled logistic regression models to estimate effects. SETTING: Medicare claims linked to nursing home electronic health record (EHR) data. PARTICIPANTS: Medicare fee-for-service beneficiaries aged 66 years or older who were admitted to a skilled-nursing facility between 1 January 2017 and 31 December 2022, had linked EHR data, had no diagnosed dementia, and were eligible for RZV. INTERVENTION: Receipt of at least 1 RZV in the facility or, if discharged, by 12 months after admission versus no receipt of RZV. MEASUREMENTS: Validated dementia diagnosis and 57 baseline and time-varying covariates. RESULTS: The study cohort included 509 926 participants (mean age, 79 years); 8843 (1.73%) received at least 1 RZV dose within 12 months after admission, and of these, 87.0% received RZV after discharge. Receipt of RZV was associated with risk for dementia being 5.8 percentage points lower (95% CI, 3.9 to 7.5 percentage points lower; risk ratio, 0.76 [CI, 0.69 to 0.84]; 4-year risk, 18.8% with ≥1 RZV vs. 24.6% with no RZV). Associations were attenuated in men and those with prior live HZ vaccination. LIMITATION: Negative control analyses suggest some residual confounding. CONCLUSION: Receipt of RZV during admission to a skilled-nursing facility or within 12 months was associated with lower dementia risk. PRIMARY FUNDING SOURCE: GlaxoSmithKline.