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

Ricardo Jorge Pais; Nuno Taveira

Importantly, our results show that the isolation measures had an immediate impact on diminishing the exponential increase of the number of infected cases and this depends on the percentage of the population that is isolated ( Figure 1B ). This is evident by the increasing deviation of the reported number of cases relative to the unperturbed simulation (0%) with time. The evolution of the number of cases reported by DGS between 18 and 25 of March fit between the simulation curves corresponding to 20% and 30% population isolation. This suggests that the estimated percentage of the population that have been effectively isolated is between these percentages. Interestingly, the data also shows a slight shift with time form being close to the 20% towards 30% suggesting that isolation behaviour of the population was gradual. From simulations, we identify other intervals (e.g. 50-60% and 70-75%) that suggest further isolation percentages may be more effective and still withing a plausible of pandemic time. Based on the fraction of hospitalized and mortality reported by the DGS on 27 March together with our model predictions, we computed several infection indicators for these intervals (Table 1 ). Model analysis indicates that current government-mandated measures may shift the expected peak of infections towards the beginning of May and can cause a substantial reduction in the infection numbers ( Figure 1C , Table 1 ). Thus, the predicted peak in the number of cases without any isolation measures would be around 2-2.5 million, whereas the intervention measures have decreased it to an estimated 1.2-0.5 million (Table 1 ). In addition, the estimated reduction of hospitalized patients and death cases on . 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.