Post-COVID research has extensively focused on the efficacy of internal travel restrictions and cross-border travel has received less attention due to challenges in accessing quality data. In a major multidisciplinary collaboration effort across Finland, Sweden, Norway, and Denmark, a group of researchers -- including mathematicians, physicists and computer scientists -- have published a pioneering study on the spread of infections across Nordic borders from spring until the end of 2020. The report sheds light on the efficacy of cross-border travel restrictions, helping us better understand which measures actually make a difference.
