The SIR model estimates incorrectly the basic reproduction number for the covid-19 epidemic (preprint)

The transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) becomes pandemic, but presents different patterns in the world. To characterize the epi- demic of coronavirus disease 2019 (covid-19) in each countries and regions, mathematical models were formulated aiming the estimation of the basic reproduction number R0. Simple mathematical model, the SIR model, provided lower estimation for R0, ranging from 1.5 to 3.0. However, more elaborate model presented here estimated higher value for R0, 9.24 and 8.0 respectively, for Sao Paulo State (Brazil) and Spain. Additionally, SIR model estimated R0 using the severe covid-19 cases, which are not participating in the SARS-CoV-2 transmission chain.

Mathematical model describing CoViD-19 in Sao Paulo State, Brazil - Evaluating isolation as control mechanism and forecasting epidemiological scenarios of release (preprint)

We formulated a mathematical model considering young (below 60 years old) and elder (above 60 years) subpopulations to describe the introduction and dissemination of new coronavirus epidemics in the Sao Paulo State, Brazil. From the data collected in Sao Paulo State, we estimated the model parameters and calculated the basic reproduction number as R0 = 6.828. Considering isolation as a control mechanism, we varied the releasing proportions of young and elder persons to assess their epidemiological impacts. The best scenarios were release of young persons, but maintaining elder persons isolated. To avoid the collapse of the health care system, the isolation must be at least 80%.

Modeling the transmission of new coronavirus in São Paulo State, Brazil -- Assessing epidemiological impacts of isolating young and elder persons (preprint)

We developed a mathematical model to describe the transmission of new coronavirus in the S\~ao Paulo State, Brazil. The model divided a community in subpopulations comprised by young and elder persons, in order to take into account higher risk of fatality among elder persons with severe CoViD-19. From data collected in the S\~ao Paulo State, we estimated the transmission and additional mortality rates, from which we calculated the basic reproduction number R0. From estimated parameters, estimation of the deaths due to CoViD-19 was three times lower than those found in literature. Considering isolation as a control mechanism, we varied isolation rates of young and elder persons in order to assess their epidemiological impacts. The epidemiological scenarios focused mainly on evaluating the number of severe CoViD-19 cases and deaths due to this disease when isolation is introduced in a population.