This paper studies the effect of the end of school summer breaks on SARS-CoV-2 cases in Germany. The staggered timing of summer breaks across federal states allows us to implement an event study design. We base our analysis on official daily counts of confirmed coronavirus infections by age groups across all 401 German counties. We consider an event window of two weeks before and four weeks after the end of summer breaks. We do not find evidence of a positive effect of school re-openings on case numbers. For individuals aged between 5 and 59 years, comprising school-aged children and their parents, our preferred specification indicates that the end of summer breaks had a negative but insignificant effect on the number of new confirmed cases. Our results are not explained by changes in mobility patterns around school re-openings arising from travel returnees. Analyses of Google Trends data suggest that behavioral changes of parents may have contributed to contain larger outbreaks after school re-openings. We conclude that school re-openings in Germany under strict hygiene measures combined with quarantine and containment measures have not increased the number of newly confirmed SARS-CoV-2 infections.

本文研究了暑假结束对德国SARS-CoV-2病例的影响。联邦各州暑假的时间错开，使我们能够实施事件研究设计。我们的分析基于德国所有401个县中按年龄段划分的官方确诊冠状病毒感染的每日计数。我们考虑在暑假结束前两周和之后四周的事件窗口。我们找不到证据表明学校重新开业对案件数量有积极影响。对于5到59岁之间的年龄段（包括学龄儿童及其父母）的个人，我们的首选规范表明，暑假的结束对新确诊病例的数量产生负面影响，但影响微不足道。旅行回国者导致学校重新开放周围的出行方式变化并不能解释我们的结果。对Google趋势数据的分析表明，父母的行为变化可能导致学校重新开放后爆发了更多疫情。我们得出的结论是，在严格的卫生措施以及检疫和遏制措施的共同作用下，德国的学校重新开放并未增加新确诊的SARS-CoV-2感染人数。