Between Geography and Demography: Key Interdependencies and Exit Mechanisms for Covid-19

Antonio Scala; Andrea Flori; Alessandro Spelta; Emanuele Brugnoli; Matteo Cinelli; Walter Quattrociocchi; Fabio Pammolli

Although the form of Eq. 6 is similar to Eq. 3, here it is not possible to consider separate evolutions for the different age classes since, differently than the inter-regional mobility matrix T , the off diagonal elements of the social matrix C a,b , a = b, measure the interaction among different age classes and are of the same magnitude of the diagonal elements C aa measuring the interaction among individuals of the same age class. Notice that Eq. 6 can be summed up, and the resulting equation can be obtained by substituting β → βC eff in Eq. 1, where C eff = ab C ab S a I b /N b SI/N is the average contact value among infected and susceptible individuals of all age classes.