Spatial distribution of full immunization and associated factors among children aged 12–23 months in Madagascar: a spatial and multilevel analysis

Immunization is one of the most cost-effective public health interventions for reducing child morbidity and mortality. However, full immunization coverage remains suboptimal in many low- and middle-income countries, including Madagascar. This study assessed the spatial distribution and determinants of full immunization among children aged 12-23 months in Madagascar. A community-based cross-sectional study was conducted using the 2021 Madagascar Demographic and Health Survey data, including 2,427 children aged 12-23 months. Spatial analysis was performed using Global Moran's I, local indicators of spatial autocorrelation, and Getis-Ord Gi* statistics to identify clustering patterns of no full immunization. Multilevel logistic regression models were fitted to examine individual- and community-level factors associated with full immunization, with adjusted odds ratios (AOR) and 95% confidence intervals (CI) reported. The prevalence of FIC was 50.9% (95% CI 48.9-52.9). Global Moran's I (0.198, p < 0.001) indicated significant spatial clustering of no full immunization. Hotspot analysis confirmed statistically significant hot spots in the central and southern regions at 90-99% confidence levels. Multilevel analysis showed that female children (AOR = 1.24, 95% CI 1.02-1.51), maternal higher education (AOR = 2.83, 95% CI 1.30-6.15), higher household wealth(AOR = 2.25, 95% CI 1.47-3.44), having media exposure(AOR = 1.32, 95% CI 1.03-1.69), , facility delivery (AOR = 1.45, 95% CI 1.16-1.83), and antenatal care utilization (AOR = 3.13, 95% CI 2.08-4.67) significantly increased the odds of full immunization. Conversely, living in communities with low maternal education reduced the odds (AOR = 0.63, 95% CI 0.46-0.86). FIC in Madagascar is low and unevenly distributed, with significant hot spots in central and southern regions. Both individual- and community-level factors influence immunization uptake. Targeted interventions focusing on identified hot spot areas, improving maternal education, expanding healthcare access, and promoting antenatal care and institutional delivery are essential to increase vaccine coverage and equity.