Abstract

Objective: This study evaluated the effect of an SMS messaging intervention on attendance at the adult vaccination clinic and vaccination rates, and determined post-counseling vaccination status, reasons for non-vaccination, and demographic characteristics associated with vaccination.

Methods: In this retrospective cross-sectional study, data of 921 patients aged ≥18 years who attended the Adult Vaccination Clinic between July and December 2024 were retrospectively analyzed. Demographic data were obtained from the Hospital Information Management System and the Vaccine Tracking System. Vaccination data from July to December 2023 were compared with those from the corresponding period in 2024 to evaluate the effect of the intervention. Categorical variables were compared using the χ2 test, Fisher’s exact test, and Fisher-Freeman-Halton exact test; p<0.05 was considered statistically significant.

Results: The mean age of the participants was 63.99 ± 16.39 years; 683 (74.2%) were aged ≥65 years, and 520 (56.5%) were male. A total of 756 participants (82.1%) reported attending the vaccination clinic after receiving an information message from the hospital. Compared with July–December 2023, 13-valent pneumococcal conjugate vaccine administration increased from 70 to 414 doses (approximately a 5.9-fold increase), and influenza vaccine administration increased from 115 to 642 doses (approximately a 5.6-fold increase) during July–December 2024. The proportion of participants who had received any vaccine during adulthood increased from 58.5% before counseling to 98.5% after counseling. Following counseling, influenza vaccination increased from 8.1% to 77.9%, while pneumococcal vaccination increased from 35.4% to 79.8%. The most common reason for refusing paid pneumococcal vaccines was that the vaccine was not covered by the government (79.6%). A statistically significant association was found between education level and both receipt of any vaccine during adulthood and vaccination at the clinic (p=0.027 and p<0.001, respectively).

Conclusion: Influenza and pneumococcal vaccination rates reached high levels, particularly among individuals aged ≥65 years and those with comorbidities following counseling at the adult vaccination clinic supported by targeted information messages.These findings suggest that information and reminder messages may support attendance at vaccination clinics and vaccination among adults. Reducing economic and logistical barriers is important for sustainably increasing vaccination rates.