Hum Vaccin Immunother. 2026 Dec;22(1):2697144. doi: 10.1080/21645515.2026.2697144. Epub 2026 Jul 29.
ABSTRACT
Evidence suggests that a substantial part of influenza-related morbidity and mortality is due to cardiovascular events. Limited population-level evidence exists regarding whether seasonal influenza vaccination is associated with a lower risk of ischemic stroke (IS) in older adults with diabetes. We conducted a retrospective cohort study using data from the Regional Health Information Platform. Among 143,841 diabetic adults aged ≥ 60 y alive and free of prior IS as of January 1, 2022, 131,045 met inclusion criteria and were followed until IS occurrence, death, or July 31, 2022. The primary outcome was first-ever IS. Vaccination exposure was receipt of the 2021/22 seasonal inactivated influenza vaccine. Subdistribution hazard ratios (sHR) and 95% confidence intervals (CI) were estimated using Fine-Gray competing risk models, with death as a competing risk. Pneumococcal vaccination served as a negative control. Of 131,045 participants, 54,617 (41.7%) received influenza vaccination. During 75,593 person-years of follow-up over approximately 7 months, 1,427 IS cases occurred (incidence rate: 18.9 per 1,000 person-years). After multivariable adjustment, influenza vaccination was associated with a 15% reduced IS risk within 7 months of follow-up (adjusted sHR = 0.85; 95% CI: 0.76-0.95). This inverse association was consistent across influenza activity phases and was most pronounced during high antigenic similarity epidemic periods (sHR = 0.74; 95% CI: 0.61-0.89) and among patients with coronary heart disease (sHR = 0.46; 95% CI: 0.25-0.86; interaction P = .034). The negative control analysis showed no association between pneumococcal vaccination and IS risk. Seasonal influenza vaccination was associated with a significantly reduced risk of incident IS within 7 months among older adults with diabetes, supporting its potential inclusion as a low-cost stroke prevention strategy in this high-risk population. Randomized controlled trials are warranted to confirm causality.
PMID:42522413 | DOI:10.1080/21645515.2026.2697144