TY - JOUR T1 - The relationship between human mobility and viral transmissibility during the COVID-19 epidemics in Italy JF - arXiv preprint arXiv:2006.03141 Y1 - 2020 A1 - Paolo Cintia A1 - Daniele Fadda A1 - Fosca Giannotti A1 - Luca Pappalardo A1 - Giulio Rossetti A1 - Dino Pedreschi A1 - S Rinzivillo A1 - Bonato, Pietro A1 - Fabbri, Francesco A1 - Penone, Francesco A1 - Savarese, Marcello A1 - Checchi, Daniele A1 - Chiaromonte, Francesca A1 - Vineis , Paolo A1 - Guzzetta, Giorgio A1 - Riccardo, Flavia A1 - Marziano, Valentina A1 - Poletti, Piero A1 - Trentini, Filippo A1 - Bella, Antonio A1 - Andrianou, Xanthi A1 - Del Manso, Martina A1 - Fabiani, Massimo A1 - Bellino, Stefania A1 - Boros, Stefano A1 - Mateo Urdiales, Alberto A1 - Vescio, Maria Fenicia A1 - Brusaferro, Silvio A1 - Rezza, Giovanni A1 - Pezzotti, Patrizio A1 - Ajelli, Marco A1 - Merler, Stefano AB - We describe in this report our studies to understand the relationship between human mobility and the spreading of COVID-19, as an aid to manage the restart of the social and economic activities after the lockdown and monitor the epidemics in the coming weeks and months. We compare the evolution (from January to May 2020) of the daily mobility flows in Italy, measured by means of nation-wide mobile phone data, and the evolution of transmissibility, measured by the net reproduction number, i.e., the mean number of secondary infections generated by one primary infector in the presence of control interventions and human behavioural adaptations. We find a striking relationship between the negative variation of mobility flows and the net reproduction number, in all Italian regions, between March 11th and March 18th, when the country entered the lockdown. This observation allows us to quantify the time needed to "switch off" the country mobility (one week) and the time required to bring the net reproduction number below 1 (one week). A reasonably simple regression model provides evidence that the net reproduction number is correlated with a region's incoming, outgoing and internal mobility. We also find a strong relationship between the number of days above the epidemic threshold before the mobility flows reduce significantly as an effect of lockdowns, and the total number of confirmed SARS-CoV-2 infections per 100k inhabitants, thus indirectly showing the effectiveness of the lockdown and the other non-pharmaceutical interventions in the containment of the contagion. Our study demonstrates the value of "big" mobility data to the monitoring of key epidemic indicators to inform choices as the epidemics unfolds in the coming months. UR - https://arxiv.org/abs/2006.03141 ER -