The effect of mHealth on childhood vaccination and its associated factors among South Ethiopian mothers: a cluster randomized controlled trial

Childhood vaccination is a cornerstone of public health, significantly reducing morbidity and mortality from vaccine-preventable diseases. However, immunization coverage remains suboptimal in many low-resource settings, including Ethiopia. Mobile health (mHealth) interventions, such as SMS reminders, have shown promise in improving healthcare service utilization, yet their effectiveness in enhancing childhood vaccination uptake remains underexplored in Ethiopia. This study assesses the impact of an mHealth intervention on childhood vaccination coverage and associated factors among mothers in the Gamo and Gofa zones of South Ethiopia. A cluster randomized controlled trial (cRCT) was conducted among 680 pregnant mothers recruited from 20 randomly selected health institutions in the Gamo and Gofa zones. Participants were assigned to either the intervention group (n = 340), which received SMS reminders and health education messages, or the control group (n = 340), which received standard care. Eligible participants were pregnant women (≥ 18 years old) with a gestational age of 16-28 weeks, literate, and able to use mobile phones. The primary outcome was childhood vaccination completion, while secondary outcomes included timely Bacillus Calmette-Guérin (BCG) vaccination at birth. Data were collected through structured interviews and analyzed using multilevel logistic regression and generalized linear mixed models. The intervention group demonstrated a significantly higher childhood vaccination completion rate (AOR = 4.80, 95% CI: 1.75-13.01, p < 0.01). Timely BCG vaccination at birth was also significantly improved in the intervention group (Log Odds = 2.19, 95% CI: 0.69-3.70, p < 0.01). Sociodemographic factors, such as maternal age, colostrum feeding, provider, and family planning, were significantly associated with vaccination uptake. The study suggests that mHealth interventions, such as SMS health information and reminders, might significantly enhance childhood vaccination coverage. Implementing mobile-based strategies could help bridge immunization gaps and support national vaccination programs. Future studies should explore the scalability of mHealth interventions in diverse settings.Clinical Trial Registration number: PACTR202211547107725; Date 22/11/2022.