Text message reminders for vaccination of adolescents with chronic medical conditions: A randomized clinical trial.

Background: Many adolescents with chronic medical conditions (CMCs) are at risk of vaccine-preventable infection, yet are frequently under-vaccinated. Text message reminders, particularly those with embedded educational information, have been shown to increase general pediatric vaccination. Their use has not been studied specifically among adolescents with CMCs.

Methods: Eligible parents of adolescents with CMCs receiving care at one of 4 academically-affiliated pediatric clinics and requiring human papillomavirus (first dose), influenza, and/or pneumococcal polysaccharide vaccines were randomized in 4 consecutive cohorts to receive text message vaccine reminders with or without embedded educational information ("educational" vs. "plain" arm, respectively). Educational reminders, including one interactive message, addressed infection risk, vaccine safety/efficacy, and physician recommendations. Up to 5 weekly and 2 booster reminders were sent (October 2014-January 2015). Receipt of any needed vaccine and missed vaccination opportunities by 4, 12, and 24weeks after the initial reminder were compared between arms.

Results: Of randomized parents (n=295), 175 (59.3%) were Spanish-speaking; most had adolescents with CMCs who were 13-17years (n=229; 77.6%) and publically insured (n=272; 92.5%). Baseline demographics and parental vaccine beliefs were similar between arms. More adolescents in the plain vs. educational reminder arm received any needed vaccine by 4weeks (31.9% vs. 22.7%, adjusted relative risk [aRR] 1.47, 95% CI 1.01-2.14), but not by 12 or 24weeks. Plain reminders were noted in post hoc analyses to have a greater effect than educational reminders in certain sub-populations, including 11-12year-olds and those sent the initial reminder in early fall. Fewer adolescents in the plain vs. educational reminder arm had a missed vaccination opportunity by 4weeks (10.9% vs. 41.3%; aRR 0.21, 95% CI 0.07-0.60), but not by 12 or 24weeks.

Conclusion: Plain text message vaccine reminders appear to have a positive effect compared to educational ones in the short-term and for certain families.

Trial Registration: NCT02231957 (www.clinicaltrials.gov).