Bridging Gaps or Widening Disparities? A Spatiotemporal Analysis of COVID-19 Therapeutic Distribution Policies in Texas

Abstract

This study examines how federal distribution policies affected regional disparities in access to COVID-19 therapeutics over time in Texas. To evaluate therapeutic accessibility, drug-to-case ratios were calculated by comparing the amount of therapeutic supply to confirmed case counts across counties during each policy period. A Bayesian spatiotemporal Integrated Nested Laplace Approximation (INLA) model was used to analyse how healthcare infrastructure, demographic characteristics, and regional vulnerabilities affected access. During the period when distribution was managed by state authorities, supply was quickly mobilized but often lagged demand, particularly in rural areas and communities with high rates of diabetes and older populations. In the next phase, test-to-treat program expanded overall supply, but access remained limited in areas with high racial and ethnic vulnerability due to the absence of demographic targeting. In the final phase, when therapeutics were allocated based on population thresholds and replenished regularly, spatial distribution became more stable and racial disparities narrowed. However, certain high-risk populations continued to face lower access. Findings show that each policy phase not only reflected but also reshaped regional disparities in therapeutic access. While early centralized efforts enabled swift response, they failed to address local needs. Later phases offered improved consistency but were still limited in addressing demographic and health-related vulnerabilities. This study underscores the importance of developing unified yet flexible distribution strategies that can respond to population-specific risks and infrastructure gaps, ensuring equitable access to treatment in future public health emergencies.