Abstract
Undernutrition and infectious diseases pose a double threat to child survival, especially in areas with a high malnutrition burden and low vaccination coverage. In this study, we evaluated whether distributing preventive small-quantity lipid-based nutrient supplements (SQ-LNS) alongside routine immunization services may increase vaccine uptake in a pediatric, pragmatic, cluster-randomized controlled trial in northern Nigeria. Twenty geographically defined clusters across two Local Government Areas were randomized 1:1 to the NutriVax strategy (intervention) or standard National Program of Immunization (NPI) services (control). NutriVax provided a monthly ration of SQ-LNS to children aged 6-23 months after routine NPI delivery at primary healthcare centers. The primary outcome was coverage of the first dose of measles-containing vaccine (MCV1) verified by vaccination card among children aged 12-23 months, assessed in an endline population-based household cross-sectional survey 12 months after conducting a similar baseline survey. The endline survey included 1,604 children (801 control, 803 NutriVax); 48% of children surveyed in intervention clusters had ever received SQ-LNS. The odds of receiving card-verified MCV1 were two times higher in the NutriVax arm than in the control arm (odds ratio = 2.08, 95% confidence interval (CI): 1.30-3.35, P = 0.004). The difference-in-differences, cluster conditional analysis indicated a 20.1 percentage-point (pp) increase in MCV1 coverage from baseline (95% CI: 13.7-26.5 pp, P < 0.0001) relative to the control arm. Co-delivering SQ-LNS with routine immunization substantially improved card-verified MCV1 uptake, supporting a scalable strategy to make progress toward targets set by the World Health Organization's Immunization Agenda 2030 in similar settings. ClinicalTrials.gov identifier: NCT06387511 .