A Centralized Text Message Recall for Pediatric Influenza Vaccination, New York City, 2017

ABSTRACT Context: Influenza vaccination coverage is suboptimal nationwide. Objectives: To evaluate the effectiveness of centralized text message recall for influenza vaccination among children conducted by the New York City Department of Health and Mental Hygiene. Design: A randomized assignment of 149 860 children, split between the intervention and control groups. Setting: Pediatric patients drawn from the Citywide Immunization Registry in New York City. Participants: Children aged 15 months to 18 years who did not receive an influenza vaccine in the 2016–2017 season and as of the study date in the 2017–2018 season. Intervention: The Citywide Immunization Registry sent a generic Short Message Service (SMS) text message to the parents or guardians of the children: “ The Health Department recommends that your child/children receive an annual flu shot. Call your doctor today! ” Main Outcome Measure: Risk ratios of the proportions of children who received an influenza vaccine in the intervention and control groups within 28 days after the text message was sent. Results: On October 25–26, 2017, 74 553 parents or guardians were sent a text message and 74 526 served as the control group. Of text messages sent, 73% were delivered successfully. Within 28 days of the intervention, 4.7% of children aged 15 months to 4 years in the text message group received an influenza vaccine compared with 4.3% in the control group, a statistically significant 9.5% relative increase in vaccination uptake (RR: 1.095, 95% CI: 1.001–1.199). Conclusions: Centralized text messages had a small positive effect on influenza vaccination among younger children. This approach may contribute to improving influenza vaccination in the pediatric population.