Measurability of the epidemic reproduction number in data-driven contact networks

Liu, Quan-Hui; Ajelli, Marco; Aleta, Alberto; Merler, Stefano; Moreno, Yamir; Vespignani, Alessandro

Predicting the future values of the age-specific susceptibility rates during a future influenza pandemic event is not possible. As such, we decided to set ρ(a) = 1 for each age a, and thus β i = β. An equally impossible task is to predict the values of the layer-specific contact rates. Therefore, we decided to fix these weights as proposed by Ferguson and colleagues by analyzing past influenza seasons [2, 3] . Following Ferguson and colleagues approach we set w l in such a way that, when simulating influenza pandemics with R index = 1.3 the fraction of the final infection attack rate related to contacts in households, schools, workplaces, and the general community is equal to 0.3, 0.18, 0.19, and 0.33. respectively. The value of R index (which is set to 1.3, in the ballpark for influenza [15] ) is obtained by empirically choosing the per-contact transmission probability p such that the average reproduction number of the index case, averaged over 10,000 simulations is equal to 1.3.