Before revision:  This model is calibrated to reproduce several characteristics of COVID-19 transmission , accounting for its reproductive number, the length of incubation and generation periods, age-dependent attack rates, and the growth rate of cumulative incidence during a sustained and unmitigated local transmission .
After revision:  This model is calibrated to reproduce key characteristics of COVID-19 transmission , accounting for its reproductive number, the length of incubation and generation periods, age-dependent attack rates, and the growth rate of cumulative incidence during a sustained and unmitigated local transmission .