International travel in times of the COVID-19 pandemic: Evidence from German school breaks

The COVID-19 pandemic has triggered severe global restrictions on international travel with the intention of limiting the spread of SARS-CoV-2 across countries. This paper studies the effects of the partial relaxation of these travel restrictions in Europe during the summer months of 2020. It exploits the staggered start of the summer school breaks across German states as an exogenous shock to the travel opportunities of the population. While the school breaks also increased mobility within Germany, the event study regressions include disaggregated and time-varying controls for domestic mobility and local COVID-19-related restrictions. The resulting intention-to-treat effects of the relaxed travel restrictions show a significant and sizable increase of the COVID-19 incidence in German counties during the later weeks of the school breaks.