Evaluating Spatial Accessibility to COVID-19 Vaccination Sites based on Fine-Scale Population Distributions and Heterogeneous Travel Modes: A Case Study in Xiangtan, China

Abstract

AbstractUnderstanding the inequity in spatial accessibility to COVID-19 vaccination sites is beneficial for the government to optimize vaccine resources. Nevertheless, the result of evaluating spatial accessibility to COVID-19 vaccination sites may be directly affected by the lack of fine-scale and accurate population distribution information in both urban and rural areas. In addition, the choice of travel modes related to different age groups has not been incorporated into existing methods well. Consequently, this study proposes a framework to evaluate spatial accessibility to COVID-19 vaccination sites based on fine-scale population distributions and heterogeneous travel modes. A divide-and-conquer strategy is first presented to estimate the fine-scale populations in both urban and rural areas. A hybrid time distance considering heterogeneous travel modes and a population-weighted proximity indicator are then defined to evaluate spatial accessibility for each age group. The experimental results from Xiangtan, China, show that (1) the divide-and-conquer strategy can effectively predict the urban and rural populations. (2) Similar clustering patterns of spatial accessibility are observed for each age group. (3) Inequities have been confirmed at the county level. The main findings in this study can provide valuable information supporting the spatial optimization of existing COVID-19 vaccination sites.