Evaluating the effects of re-opening plans on dynamics of COVID-19 in São Paulo, Brazil ¹

Coronavirus disease 2019 (COVID-19) was declared a pandemic by the World Health Organization in early March 2020. In Brazil, São Paulo is the most affected state, comprising about 20% of the country’s cases. With no vaccine available to date, distancing measures have been taken to reduce virus transmission. To reduce the pandemic’s effect on the economy, the government of São Paulo has proposed a plan consisting of five phases of the gradual re-opening of activities. In this context, we have developed a mathematical model to simulate the gradual re-opening plan on the transmission dynamics of COVID-19, in the city of São Paulo. The model shows that a precipitous reopening can cause a higher peak of the disease, which may compromise the local health system. Waiting for the reduction in the incidence of infected individuals for at least 15 days to phase transition is the most efficient strategy compared to the fixed-period scenario at each phase of the re-opening plan.