Predicting the evolution and control of COVID-19 pandemic in Portugal.

Ricardo Jorge Pais; Nuno Taveira

Basic transmission dynamics of COVID-19 was modelled using a simple mathematical model based on a system of two ordinary differential equations (ODE) developed specifically for this purpose (see equations on Figure 1A ). The equations reflect the number of people infected (I) and susceptible (S) to infection per unit of time (dI/dt and dS/dt). In this model, we accounted for the reported average time of duration of infection (τ) of 14 days [6] . Model was calibrated by adjusting the rate constant (k) to approximate the total infection value reported by the DGS at 17 March. No further fitting was performed in this model. The effect of isolating different fractions of the population was modelled through the variation of parameter α in equations. We assumed that protective measures were 99% effective, accounted through model parameter β. The ODEs were solved using PLAS software and series of simulations were carried scanning various values of the α parameter [7] . Simulations were carried with the . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.