Abstract
This cluster-randomized controlled trial evaluated the efficacy of a mobile health (mHealth) interpersonal communication intervention on childhood immunization completion rates among pastoralist communities in northern Kenya. Over a 12-month period, 24 nomadic settlements (clusters) in Marsabit County were randomly assigned to either an intervention group receiving targeted SMS reminders combined with community health volunteer (CHV) phone-based interpersonal engagement, or a control group receiving standard care. Data were collected from 412 mother-infant pairs (infants aged 0-12 months). The primary outcome was the completion of the basic childhood immunization schedule by 12 months of age. Baseline immunization completion in these remote, pastoralist settings was low (approximately 34%). At the end of the trial, the intervention group demonstrated a significantly higher immunization completion rate of 68.2% compared to 41.5% in the control group (risk ratio = 1.64, 95% CI: 1.32–2.04, p < 0.001). Multivariable logistic regression confirmed that the combination of automated SMS alerts and personalized CHV follow-ups significantly mitigated geographical and educational barriers to vaccine uptake. These findings indicate that mobile-enabled interpersonal communication strategies are highly effective in bridging healthcare delivery gaps in hard-to-reach, mobile populations. Implementing such digital health frameworks at scale could dramatically improve vaccine coverage and equity in sub-Saharan African pastoralist contexts.
