Fine-scale variation in the effect of national border on COVID-19 spread: A case study of the Saxon-Czech border region

The global extent and temporally asynchronous pattern of COVID-19 spread have repeatedly highlighted the role of international borders in the fight against the pandemic. Additionally, the deluge of high resolution, spatially referenced epidemiological data generated by the pandemic provides new opportunities to study disease transmission at heretofore inaccessible scales. Existing studies of cross-border infection fluxes, for both COVID-19 and other diseases, have largely focused on characterizing overall border effects. Here, we couple fine-scale incidence data with localized regression models to quantify spatial variation in the inhibitory effect of an in-ternational border. We take as a case study the border region between the German state of Saxony and the neighboring regions in northwestern Czechia, where municipality-level COVID-19 incidence data are available on both sides of the border. Consistent with past studies, we find an overall inhibitory effect of the border, but with a clear asymmetry, where the inhibitory effect is stronger from Saxony to Czechia than vice versa. Furthermore, we identify marked spatial variation along the border in the degree to which disease spread was inhibited. In particular, the area around Lo center dot bau in Saxony appears to have been a hotspot for cross-border disease transmission. The ability to identify infection flux hotspots along international borders may help to tailor monitoring programs and response measures to more effectively limit disease spread.

Automated summary

The global and temporally asynchronous spread of COVID-19 has emphasized the role of international borders in combating the pandemic. The availability of high-resolution, spatially referenced epidemiological data presents new opportunities to study disease transmission. This study focuses on the German-Czech border region and finds an overall inhibitory effect of the border, with stronger inhibition from Saxony to Czechia. Spatial variation along the border is also observed, with the Lo center dot bau area in Saxony identified as a hotspot for cross-border disease transmission.