SMS text message reminders to improve infant vaccination coverage in Guatemala: A pilot randomized controlled trial

BACKGROUND: Patient reminder systems are an evidence-based way to improve childhood vaccination rates but are difficult to implement in low- and middle-income countries (LMICs). Short Message Service (SMS) texts may offer a potential low-cost solution, especially in LMICs where mobile phones are becoming more ubiquitous. OBJECTIVE: To determine if an SMS-based vaccination reminder system aimed at improving completion of the infant primary immunization series is feasible and acceptable in Guatemala. METHODS: A pilot randomized controlled trial was conducted at two public health clinics in Guatemala City. Infants aged 8–14 weeks presenting for the first dose of the primary immunization series were enrolled in March–April 2013. Participants randomized into the intervention received three SMS reminders one week before the second and third dose. A follow-up acceptability survey was administered to both groups. RESULTS: The participation rate was 86.8% (321/370); 8 did not own a cell phone and 12 could not use SMS. 96.9% of intervention parents were sent at least one SMS reminder prior to visit 2 and 96.3% prior to visit 3. Both intervention and usual care participants had high rates of vaccine and visit completion, with a non-statistically significant higher percentage of children in the intervention completing both visit 2 (95.0% vs. 90.1%, p = .12) and visit 3 (84.4% vs. 80.7%, p = .69). More intervention vs. usual care parents agreed that SMS reminders would be helpful for remembering appointments (p < .0001), agreed to being interested in receiving future SMS reminders (p < .0001), and said that they would be willing to pay for future SMS reminders (p = .01). CONCLUSION: This proof of concept evaluation showed that a new application of SMS technology is feasible to implement in a LMIC with high user satisfaction. Larger studies with modifications in the SMS system are needed to determine effectiveness (Clinical Trial Registry NCT01663636).