A spatial analysis of COVID-19 period prevalence in US counties through June 28, 2020: Where geography matters?

Abstract Purpose This study aims to understand how spatial structures, the interconnections between counties, matter in understanding COVID-19 period prevalence across the US. Methods We assemble a county-level dataset that contains COVID-19 confirmed cases through June 28, 2020 and various sociodemographic measures from multiple sources. In addition to an aspatial regression model, we conduct spatial lag, spatial error, and spatial autoregressive combined models to systematically examine the role of spatial structure in shaping geographical disparities in COVID-19 period prevalence. Results The aspatial ordinary least squares regression model tends to overestimate the COVID-19 period prevalence among counties with low observed rates, but this issue can be effectively addressed by spatial modeling. Spatial models can better estimate the period prevalence for counties, especially along the Atlantic coasts and through the Black Belt. Overall, the model fit among counties along both coasts is generally good with little variability evident, but in the Plain states, model fit is conspicuous in its heterogeneity across counties. Conclusions Spatial models can help partially explain the geographic disparities in COVID-19 period prevalence. These models reveal spatial variability in model fit including identifying regions of the country where fit is heterogeneous and worth closer attention in the immediate short term.