Title : Mapping the invisible: Targeted micro-planning to eliminate zero-dose immunization gaps in urban megacities
Abstract:
Background: Zero-dose children, those who have never received a single vaccine represent the sharpest edge of immunization inequity worldwide. In Lagos, Nigeria’s megacity of over 15 million, high-density settlements, complex migration patterns, population fluidity, and fragmented subnational data systems obscure these vulnerable populations from traditional surveillance. Solving this challenge demands a precision strategy that blends grassroots intelligence, adaptive outreach, and digital innovation for last-mile visibility.
Methods: Between January and June 2025, Lagos State piloted hyperlocal routine immunization (RI) microplanning in Alimosho and Ikorodu areas—its most underserved areas challenged by informal settlements and data fragmentation. The approach deployed GIS-assisted settlement mapping to delineate catchment areas, triangulated community informant networks to surface hidden zero-dose clusters, and zero-dose child registries integrated into workflows. Tailored outreach campaigns—engaging religious leaders, market associations, and mobile influencers—addressed vaccine hesitancy with culturally resonant messaging. Facility dashboards and DHIS2 analytics tracked Penta1 uptake, dropout trends, and geospatial patterns. Rapid ethnographic assessments informed outreach design, digital mapping validated boundaries. Capacity-building enabled frontline workers and ward focal persons to use mobile tools for dynamic tracking and last-mile service delivery.
Results: A 41% increase in zero-dose identification through robust triangulated community informant networks and mobile registry validation. Penta1 coverage rose from 68.1% to 84.5% in Alimosho and from 71.3% to 83.6% in Ikorodu following targeted outreach and settlement mapping. Dropout rates fell 28.6%, reflecting stronger caregiver follow-up and improved service continuity. A strong correlation between household density and access gaps (r = 0.81, p < 0.001) validated spatial mapping as a predictive tool for resource allocation and hotspot prioritization in urban settings.
Conclusion: This approach offers a scalable framework for urban vaccine equity, where digital tools and local insights converge to locate and immunize invisible populations. Lagos emerges as a living laboratory for integrating innovation into public health planning to close zero-dose gaps.
Keywords: DHIS2 analytics, dropout rate reduction, GIS-assisted mapping, microplanning, mobile outreach tools, penta1 coverage
