The effect of short message reminders on seasonal influenza vaccination rates in the geriatric population.

Seasonal influenza causes substantial morbidity and mortality in older adults, yet vaccination coverage in this population remains low. This study evaluated the association between short message service (SMS)-based informational and reminder messages and influenza vaccination uptake among adults aged 65 y and older. In this single-center prospective study, an SMS reminder was sent at the beginning of the 2024-2025 influenza season to 1690 individuals aged ≥65 y who had attended a family medicine outpatient clinic during the previous season. Demographic characteristics and prior-season influenza vaccination status were obtained from electronic medical records. At the end of the season, participants were contacted by telephone, and 338 individuals who completed follow-up were included in the final analysis. Influenza vaccination uptake increased from 16.9% in the 2023-2024 season to 31.4% in the 2024-2025 season, corresponding to an absolute increase of 14.5% points (p < .001). Among individuals vaccinated in the previous season, 52.6% were vaccinated again, while 27.0% of those unvaccinated in the previous season received the vaccine in the current season. In age-stratified analyses, the increase was significant in the young-old group (65-74 y) but not in the older age groups. In binary logistic regression analysis, prior-season influenza vaccination was the only factor significantly associated with current-season vaccination (OR,2.960; 95% CI,1.650-5.309; p < .001). Influenza vaccination uptake was significantly higher during the season in which SMS reminders were sent, suggesting that text messaging may support vaccination coverage among older adults, although additional age-tailored strategies may be needed for older subgroups.