Since the end of July, the number of new infections with the coronavirus has been on the rise again in Germany. Because of falling temperatures and group activities being relocated indoors, the pandemic's development is at risk of becoming difficult to control again. In its ad-hoc-statement “Coronavirus pandemic: Establishing effective rules for autumn and winter” the German National Academy of Sciences Leopoldina points out that to counter this threat in time and maintain public life in the coming months, protective measures must be taken now. The Leopoldina appeals to all responsible parties at the federal and state levels to quickly agree on national, effective, and standardized rules for preventive measures and to ensure that these measures are implemented and complied with more consistently than has been the case to date.