  Mobility data at EU scale can help understand the dynamics of the pandemic
and possibly limit the impact of future waves. Still, since a reliable and
consistent method to measure the evolution of contagion at international level
is missing, a systematic analysis of the relationship between human mobility
and virus spread has never been conducted. A notable exceptions are France and
Italy, for which data on excess deaths, an indirect indicator which is
generally considered to be less affected by national and regional assumptions,
are available at department and municipality level, respectively. Using this
information together with anonymised and aggregated mobile data, this study
shows that mobility alone can explain up to 92% of the initial spread in these
two EU countries, while it has a slow decay effect after lockdown measures,
meaning that mobility restrictions seem to have effectively contribute to save
lives. It also emerges that internal mobility is more important than mobility
across provinces and that the typical lagged positive effect of reduced human
mobility on reducing excess deaths is around 14-20 days. An analogous analysis
relative to Spain, for which an IgG SARS-Cov-2 antibody screening study at
province level is used instead of excess deaths statistics, confirms the
findings. The same approach adopted in this study can be easily extended to
other European countries, as soon as reliable data on the spreading of the
virus at a suitable level of granularity will be available. Looking at past
data, relative to the initial phase of the outbreak in EU Member States, this
study shows in which extent the spreading of the virus and human mobility are
connected.
