Realized generation times: contraction and impact of infectious period, reproduction number and population size

Andrea Torneri; Amin Azmon; Christel Faes; Eben Kenah; Gianpaolo Scalia Tomba; Jacco Wallinga; Niel Hens

This paper's focus is on the evolution over time of the mean forward generation time 310 but the backward generation scheme is of interest too. The mean backward generation 311 time is known to be increasing [6, 20] and differently from the forward scheme a single 312 generation is considered for every time point. The increasing trend is due to the fact 313 that the probability of encountering a susceptible decreases over time, but a more 314 intense competition can, also in this case, modify the evolution of the mean value over 315 time. This is shown in Fig S6, where in a preliminary investigation the baseline, Although we have looked at compartmental SIR models, we expect our conclusion to 331 hold for more complicated compartmental models, and even for epidemics models on 332 structured contact networks. A limitation of our investigation is the assumption made 333 for the infectious contact process to be described by a Poisson process and to be 334 homogeneous in the population: in a structured population the infectious contact 335 process depends on the location where the contacts take place because of different 336 behaviour of individuals yielding different contact processes [21] .