Characterizing key attributes of the epidemiology of COVID-19 in China: Model-based estimations

Houssein H Ayoub; Hiam Chemaitelly; Ghina R Mumtaz; Shaheen Seedat; Susanne F Awad; Monia Makhoul; Laith J Abu-Raddad

The model was expressed in terms of a system of coupled nonlinear differential equations for each age group. The index a denotes the different age cohorts ( ) 1, 2,...,9 a = in the population, with each age group representing a ten-year age band apart from the last one (those ≥80 years of age). The population size and demographic structure were set by China's demography as provided by the United Nations World Population Prospects database [1] . However, the population size and distribution across age groups were fixed at 2020 levels, to disentangle the epidemiologic and demographic effects-a valid assumption given that the current time scale of the epidemic is only few months. All COVID-19 mortality was assumed to occur in individuals that are in the critical disease stage, as informed by the China outbreak data [2] .