Spatial patterns and factors associated with vaccination uptake at follow-up among previously identified zero-dose children in Mchinji District, Malawi

Abstract

Globally, more than 14 million infants remained zero-dose in 2024, having not received the first dose of diphtheria-tetanus-pertussis-containing vaccine (DTP1). In Malawi, national immunisation estimates may mask sub-district inequities, limiting the ability to identify and reach persistently missed populations. This study mapped the spatial distribution of zero-dose children in Mchinji District and assessed geographic, caregiver-, and household-level factors associated with vaccination uptake at follow-up among previously identified zero-dose children. We conducted a cross-sectional study of 135 caregivers of zero-dose children (aged 0–59 months) identified during the July 2024 Periodic Intensification of Routine Immunisation (PIRI) campaign in three high-burden catchment areas of Mchinji District, Malawi. Spatial clustering was assessed using Global Moran’s I and Getis-Ord Gi* hotspot analysis with AccessMod travel-time modelling. Associations with vaccination status were examined using multivariable logistic regression. Zero-dose children showed modest but statistically significant spatial autocorrelation (Moran’s I = 0.0405, p = 0.035), concentrated in geographically remote areas with travel times exceeding two hours to the nearest immunisation service. At follow-up, 68.1% (92/135) had been vaccinated. In adjusted analysis, higher household income (OR 6.80, 95% CI: 1.24–46.1), use of non-walking transport (OR 8.89, 95% CI: 1.62–79.8), and caregiver knowledge of the required number of immunisation visits (OR 8.07, 95% CI: 2.36–36.3) were independently associated with vaccination. Zero-dose children in Mchinji were clustered in remote, high travel-time villages, highlighting sub-district inequities. Fine-scale geospatial mapping and travel-time modelling can identify actionable hotspots to guide geo-enabled microplanning, including outreach placement, mobile or temporary sites, and targeted demand-generation aligned with Immunization Agenda 2030 equity goals.