Implementing SMS reminders for routine immunization in Northern Nigeria: a qualitative evaluation using the RE-AIM framework

Background:Short Message Service (SMS) reminders have improved vaccine uptake in low- and middle-income countries (LMICs). However, the limited use of SMS reminders in LMICs requires evaluating the intervention's internal and external validity to improve adoption and sustainability. Using the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework, we qualitatively assessed the impact of a SMS reminder intervention implemented in Kebbi State, Northwest Nigeria between May 20, 2019 and May 31, 2020. This will guide and inform future SMS reminder interventions to improve childhood immunization uptake in LMICs. Methods:In June 2020, we conducted 14 focus group discussions, 13 in-depth interviews, and 20 key informant interviews among 144 purposively selected participants from five local government areas of Kebbi State. For analysis, we used a deductive approach to develop preliminary codes based on the RE-AIM framework and the inductive approach to generate themes that emerged from the interviews. Results:The perceived importance and impact of the SMS reminder in improving demand and uptake for vaccinations were the consistent contributing factors that encouraged participants' participation. Other facilitators included the involvement of health workers in supporting SMS reminder registration and community gatekeepers using existing structures to convey messages on scheduled immunization services. Policymakers adopted the intervention because it aligns with the state's priority to improve immunization coverage. Similarly, the SMS reminder appealed to health workers and program managers because it reduced their workload and served as a performance monitoring tool to track immunization and intervention defaulters. Despite these, low mobile phone ownership and the inability to read text messages due to the low literacy level were the main barriers during implementation. Finally, data availability on cost-effectiveness and the intervention's impact on improving coverage was critical for scalability. Conclusions:Our study demonstrated that SMS reminders in local languages could improve vaccination demand and uptake in resource-constrained settings due to their perceived importance and impact. Addressing the cited implementation barriers and promoting the facilitators is critical to its adoption and sustainability. Costing and impact data are needed to collaborate findings on the effectiveness of the SMS reminder to improve childhood vaccination uptake.