Schematic illustration of the GLobal Epidemic and Mobility (GLEaM) model. Top: census and mobility layers that define the subpopulations and the various types of mobility among those (commuting patterns and air travel flows). The same resolution is used worldwide. Bottom: compartmental structure in each subpopulation. A susceptible individual in contact with a symptomatic or asymptomatic infectious person contracts the infection at rate β or r
ββ [30, 32], respectively, and enters the latent compartment where he is infected but not yet infectious. At the end of the latency period, each latent individual becomes infectious, entering the symptomatic compartments with probability 1 - p
a or becoming asymptomatic with probability p
a [30, 32]. The symptomatic cases are further divided between those who are allowed to travel (with probability p
t) and those who would stop traveling when ill (with probability 1 - p
t) . Infectious individuals recover permanently with rate μ. All transition processes are modeled through multinomial processes.