Evaluating epidemiological scenarios of isolation and further releases considering protection actions to control transmission of CoViD-19 in Sao Paulo State, Brazil.

Yang, H. M.; Lombardi Junior, L. P. P.; Castro, F. F. M.; Yang, A. C.

A mathematical model was formulated based on nonlinear ordinary differential equations considering young (below 60 years old) and elder (above 60 years) subpopulations, aiming to describe the introduction, dissemination and control of new coronavirus in Sao Paulo State, Brazil. In Sao Paulo State, the first case of CoViD-19 was confirmed on 26 February, the first death due to CoViD-19 was registered on 16 March, on 24 March the Sao Paulo State authorities implemented the isolation of persons in non-essential activities, which is programmed to end on June 1. The deterministic model used the data collected in Sao Paulo State to estimate the model parameters to describe the current epidemiological status in the State under isolation. We concluded that the proportion in isolation influenced the number of new cases in around 9 days ahead. We evaluate the suitability of lockdown in Sao Paulo State and concluded that this extreme measure should be efficient if lower transmission is occurring among isolated persons. Nevertheless, the isolated persons must be released one day. Based on this model, we studied the potential epidemiological scenarios of release by varying the release proportions of young and elder persons. We evaluated three releases divided in equal proportions elapsed 14 days between releases, and three strategies: the first release occurring on June 1, 15 and 23. We concluded that these three strategies are equivalent (little difference) in reducing the number of hospitalization due to severe CoViD-19 and deaths, due to presenting the effective reproduction number near one. However, if protection actions as using face mask and hygiene (washing hands, for instance) could be massively disseminated in the population, we concluded there health care system may not collapse.