Impact of urban structure on COVID-19 spread

Javier Aguilar1, Aleix Bassolas2, Gourab Ghoshal3,4, Surendra Hazarie3, Alec Kirkley5, Mattia Mazzoli1,
Sandro Meloni1, Sayat Mimar3, Vincenzo Nicosia2, José J. Ramasco1 and Adam Sadilek6

1Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (CSIC-UIB), Palma de Mallorca, Spain.
2School of Mathematical Sciences, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
3Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA.
4Department of Computer Science, University of Rochester, Rochester, NY 14627, USA.
5Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
6Google Inc., 1600 Amphitheatre Parkway, Mountain View, CA 94043, USA.

(August 2020)

The ongoing COVID-19 pandemic has created a global crisis of massive scale. Prior research indicates that human mobility is one of the key factors involved in viral spreading. Indeed, in a connected planet, rapid world-wide spread is enabled by long-distance air-, land- and sea-transportation among countries and continents, and subsequently fostered by commuting trips within densely populated cities. While early travel restrictions contribute to delayed disease spread, their utility is much reduced if the disease has a long incubation period or if there is asymptomatic transmission. Given the lack of vaccines, public health officials have mainly relied on non-pharmaceutical interventions, including social distancing measures, curfews, and stay-at-home orders. Here we study the impact of city organization on its susceptibility to disease spread, and amenability to interventions. Cities can be classified according to their mobility in a spectrum between compact-hierarchical and decentralized-sprawled. Our results show that even though hierarchical cities are more susceptible to the rapid spread of epidemics, their organization makes mobility restrictions quite effective. Conversely, sprawled cities are characterized by a much slower initial spread, but are less responsive to mobility restrictions. These findings hold globally across cities in diverse geographical locations and a broad range of sizes. Our empirical measurements are confirmed by a simulation of COVID-19 spread in urban areas through a compartmental model. These results suggest that investing resources on early monitoring and prompt ad-hoc interventions in more vulnerable cities may prove most helpful in containing and reducing the impact of present and future pandemics.