Before revision:  In particular, we consider Italian regions as separate administrative entities  in which social interactions through different age classes occur. We find that, due to the sparsity of the mobility matrix, epidemics  develop independently in different regions once the outbreak starts.
After revision:  In particular, we consider Italian regions as separate administrative entities in which social interactions between age cohorts occur. Due to the sparsity of the mobility matrix, epidemics develop independently in different regions once the outbreak starts.