COVID-19 lockdown induces disease-mitigating structural changes in mobility networks

TL;DR

The COVID-19 lockdown in Germany caused significant, lasting structural changes in mobility networks, reducing long-distance travel, increasing local clustering, and impacting epidemic spread dynamics.

Contribution

This study reveals that lockdown measures induce persistent structural changes in mobility networks, affecting disease transmission models and epidemic control strategies.

Findings

Long-distance travel was disproportionately reduced.

Mobility networks became more localized and clustered.

Structural changes delayed and flattened epidemic spread.

Abstract

In the wake of the COVID-19 pandemic many countries implemented containment measures to reduce disease transmission. Studies using digital data sources show that the mobility of individuals was effectively reduced in multiple countries. However, it remains unclear whether these reductions caused deeper structural changes in mobility networks, and how such changes may affect dynamic processes on the network. Here we use movement data of mobile phone users to show that mobility in Germany has not only been reduced considerably: Lockdown measures caused substantial and long-lasting structural changes in the mobility network. We find that long-distance travel was reduced disproportionately strongly. The trimming of long-range network connectivity leads to a more local, clustered network and a moderation of the "small-world" effect. We demonstrate that these structural changes have a considerable effect on epidemic spreading processes by "flattening" the epidemic curve and delaying the spread to geographically distant regions.