Conflict and displacement as drivers of first‑dose measles vaccine coverage in Somalia: An ecological analysis

Background Measles remains a persistent public health challenge in Somalia, where decades of conflict and population displacement complicate immunization efforts. Understanding how spatial patterns of insecurity align with vaccination coverage is critical for identifying barriers to effective service delivery and patient outcomes. Guided by the Critical Success Factors (CSF) Framework, this study assesses how district-level conflict intensity and displacement trends influence routine measles first-dose vaccine coverage in fragile settings. Methods This study employed an ecological design to assess whether district-level conflict and patterns of displacement were related to trends in measles vaccine first-dose (MCV1) coverage in Somalia from 2015 to 2023. Spatial clustering of conflict events was assessed using Global Moran’s I, and district-level hotspots were identified via Getis-Ord Gi* statistics. Hotspot prevalence trends were compared against annual MCV1 coverage estimates to examine temporal alignment. Multivariable ordinary least squares (OLS) regression with year fixed effects and district-clustered robust standard errors evaluated associations between coverage and five predictors: hotspot prevalence, internally displaced persons (IDP) count, population density, health facility availability, and urban/rural classification. Results Conflict events showed statistically significant spatial clustering (Moran’s I = 0.228, p < .001), with nine districts identified as hotspots in 2023. Hotspot prevalence peaked at 16.2% in 2020, declining to 12.2% by 2023. National MCV1 coverage remained stable at 46%, despite rising displacement volumes. OLS regression models showed no statistically significant associations between instability indicators and vaccine coverage. Model diagnostics supported adequacy. Conclusions Although conflict and displacement patterns did not show a measurable relationship with national MCV1 coverage trends, the integration of spatial diagnostics and regression analysis reveals how geospatial methods can expose structural blind spots in vaccine monitoring systems. These findings highlight the need for context-sensitive strategies to improve immunization equity in settings affected by conflict and displacement.