Fig. 1.

Model A: Scheme of the 2-step approach. Step 1 is based on the fit of 20 imputed epidemic curves for each of the 17 regions in the Middle East (only one curve is displayed for the sake of visualisation corresponding to the region experiencing the largest number of cases). It allows model selection and estimation of R^r(t) and $q_{sp}^r(t)=\rho p_{sp}^r(t)$. Step 2 is based on the fit of imported cases in Western Europe and North America and allows estimating ρ. B: Scheme of the functional forms assumed for R(t) and q_sp(t) when temporal heterogeneity (either for one of the parameters or both) is considered in the model. Parameters q_sp,1, q_sp,2, R₁, R₂, R₃ are estimated. C: Combination of parameters yielding the 32 models for exploration.