Subnational Inequities in Measles Vaccination Coverage in Kenya: A Bayesian Geostatistical Modelling Analysis

Abstract Background Subnational inequalities in measles vaccination coverage remain a major barrier to elimination, particularly in low- and middle-income countries. In Kenya, national averages mask substantial geographic and socioeconomic disparities in measles-containing vaccine (MCV) coverage. We aimed to generate high-resolution estimates of first- and second-dose measles coverage (MCV1 and MCV2), identify subnational inequities, and quantify gaps relative to WHO targets. Methods We analysed vaccination data for 7,307 children aged 12–35 months from the 2022 Kenya Demographic and Health Survey using Bayesian geostatistical modelling. Cluster-level vaccination data were combined with environmental, socio-economic, and health-system covariates to produce MCV1 and MCV2 coverage estimates at 5x5km resolution, aggregated to county and sub-county levels. We estimated probabilities of achieving 80% and 95% coverage and the number of unvaccinated children by location and dose. Findings Design-adjusted DHS estimates showed 53.2% of counties achieved ≥ 90% MCV1 coverage, including 27.7% meeting the WHO ≥ 95% target. MCV2 coverage was markedly lower: no county reached ≥ 95%, and just over one quarter exceeded 80%. Model–based estimates indicated national coverage of 86.1% (95% credible interval [CrI] 84.5–87.4) for MCV1 and 63.0% (60.4–64.8) for MCV2, representing a drop-off of more than 20 percentage points between doses. Spatial heterogeneity was observed, with persistently low coverage in northern and north-eastern Kenya and pockets of underperformance within higher-coverage counties. The probability of attaining ≥ 95% coverage was uniformly low across nearly all counties and sub-counties. Higher maternal literacy and shorter motorized travel time to health facilities were consistently associated with higher uptake of both doses. Conclusion Despite high first-dose measles coverage in many counties, large second-dose gaps and pronounced subnational inequities threaten elimination efforts in Kenya.