AS01-Adjuvanted Shingles and RSV Vaccines Linked to Lower Dementia Risk
A new retrospective cohort study of over 436,000 individuals suggests that AS01-adjuvanted vaccines—used in recombinant shingles (Shingrix) and RSV (Arexvy) immunization—are independently associated with a reduced risk of dementia diagnosis over 18 months, relative to flu vaccination. Findings were published in a Brief Communication in npj Vaccines.
The analysis, based on US Electronic Health Records (EHRs) from the TriNetX network, offers evidence that the AS01 adjuvant may play a neuroprotective role, beyond infection prevention.
The study included 3 exposure cohorts: those receiving only AS01 RSV, only AS01 shingles, or both, each matched to controls who received only a flu vaccine. Participants were followed for 18 months postvaccination. Covariates were extensively matched (66 total), and dementia was assessed through ICD-10-coded diagnoses. The study used restricted mean time lost (RMTL) instead of Cox models due to non-proportional hazards.
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Compared to those who received the flu vaccine, patients who received the AS01 RSV vaccine had a 29% lower risk of dementia (RMTL ratio, 0.71, 95% CI: 0.61–0.83, P = 2.8 × 10−5), while those receiving the AS01 shingles vaccine had an 18% reduction (RMTL: 0.82, 95% CI: 0.74–0.91, P = .00027). Those vaccinated with both had a 37% reduction (RMTL: 0.63, 95% CI: 0.55–0.72, P = 4.7 × 10−12), yet no additive effect was found compared with receiving only one, indicating a possible saturation of benefit from the AS01 adjuvant.
Authors acknowledge limitations including diagnostic delay, the absence of vaccination brand data in a subset (resulting in potential inclusion of non-AS01 RSV vaccines), and the use of observational data. “The findings may be affected by bias due to unmeasured confounding,” they caution.
Clinicians might consider these findings when evaluating vaccine strategies in older adults, particularly as evidence grows supporting the broader neurologic benefits of adjuvanted immunization.
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