Mobility restrictions are more than transient reduction of travel activities

The world is getting closer, enabling far-ranging human movements as well as disease diffusions (1). This greater interconnectedness has drawn our attention to a core feature of the real world—the “small-world” characteristic (2). Thinking from a network perspective, the world consists of closely connected communities which are bridged by random, long-distance connections. However, this network structure has made the world more vulnerable to infectious disease. During the early stage of the COVID-19 pandemic, mobility restrictions such as lockdown measures have proven their worth in mitigating disease spread (3⇓–5). The current challenge is averting disease burden while promoting socioeconomic recovery. In order to craft solutions, we really need to detail and translate the effect of mobility restrictions. Schlosser et al. (6) bring us answers to two key questions surrounding the effect of COVID-19 lockdown: How does the structural mobility network change? What are the impacts on epidemic spreading? The authors use mobile phone data to uncover structural changes in mobility in Germany during the pandemic. They show a profound restructuring of the mobility network—a more local, clustered network by reducing long-distance travels. They relate this structure to epidemic transmission, pointing to the prominent effectiveness of this structural change to suppress epidemic curves and slow down the spatial spread. This study underscores the complex consequences of mobility restrictions, for policymakers, and provides general implications for similar scenarios in the future