Providing mothers with mobile phone message reminders increases childhood immunization and vitamin A supplementation coverage in Cote d'Ivoire: A randomized controlled trial

We conducted a randomized controlled trial to assess the effect of providing mothers with mobile voice or text (SMS) reminder messages on health facility attendance at five infant immunization and vitamin A supplementation (VAS) visits. The study was conducted at 29 health facilities in Korhogo district. Mothers were randomized to receive a voice or text reminder message two days prior to each scheduled visit and two additional reminders for missed doses (n=798; intervention group), or no phone reminder messages (n=798; control group). Infants in the intervention group were 2.85 (95% CI: 1.85-4.37), 2.80 (95% CI: 1.88-4.17), 2.68 (95% CI: 1.84-3.91), and 4.52 (95% CI: 2.84-7.20) times more likely to receive pentavalent 1-3 and MMR/yellow fever doses, respectively, and 5.67 (95% CI: 3.48-9.23) times more likely to receive VAS, as compared to the control group. In the reminder group, 58.3% of infants completed all five visits, compared to 35.7% in the control group (P<0.001). Providing mothers mobile phone message reminders is a potentially effective strategy for improving immunization and VAS coverage in Cote d'Ivoire.