Attempts to constrain the spread of Covid-19 included the temporal reintroduction of travel restrictions and border controls within the Schengen area. While such restrictions clearly involve costs, their benefits have been disputed. Using a new set of daily regional data of confirmed Covid-19 cases from the respective statistical agencies of 18 Western European countries Matthias Eckardt, Kalle Kappner and Nikolaus Wolf suggest that border controls had a significant effect to limit the pandemic.