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

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.

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.

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.

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).

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).