Evaluation of the potential incidence of COVID-19 and effectiveness of contention measures in Spain: a data-driven approach

Alberto Aleta; Yamir Moreno

Complementarily to Figure 4 , we present in Figure 5 further results on the temporal and spatial evolution of the disease dynamics. Here we have computed, through stochastic simulations of the model, the cumulative number of infected individuals within each region assuming that the disease propagates from Barcelona by 10 initially infected individuals. The results align with the theoretical predictions, and highlight the close relationship that exists between the two biggest cities of Spain (Barcelona and Madrid), even though they are relatively far geographically (around 620 kilometers through the shortest path by car). Again, note that the relative slow speed of the epidemic agrees with what has been observed in China. Finally, it is worth remarking that all of these quantities have been obtained assuming that no control measures are taken, which is not the current case as (detected) infected individuals are being isolated and monitored by the authorities. Additionally, we also stress that it is difficult to assess whether this corresponds to a worst-case projection or not, given the many unknowns that can't be taken into account, such as inflow of infected subjects from abroad, the fraction of infectious individuals that have gone undetected, etc. However, as we show next, this data-driven modeling approach do allow to evaluate the effect of customary contention measures.