Data-Driven Study of the the COVID-19 Pandemic via Age-Structured Modelling and Prediction of the Health System Failure in Brazil amid Diverse Intervention Strategies

Askery Canabarro; Elayne Tenorio; Renato Martins; Lais Martins; Samurai Brito; Rafael Chaves

In the absence of a vaccine, the behavior of the individuals takes a crucial role in the course of an epidemic such as the COVID-19 in Brazil. In a nutshell, and as schematically shown in Fig. 1 , susceptible (S) individuals can become infected mainly by direct interaction with infected (I) persons at a rate β, who can recover (R) at a rate α and become resistant to the virus or die (D) at a rate γ. If, on average, one infected person contaminates one or more individuals, the epidemic is sustainable, otherwise it dies out. This is the definition of the basic reproduction number (R 0 ), which represents the average number of secondary cases from a single infectious case in a totally susceptible population (in the very beginning of the infection the susceptible population corresponds approximately to the total population N , S ≈ N ), defined as R 0 = β/(α + γ). Therefore, it is very important to reduce the transmission rate in order to reduce the subsequent reproduction ratio R n (not to mistaken with the number of recovered individuals) so that R n < 1 and the epidemic fades out. In the unlikely worst case scenario in which the government does not impose any measures for containing the infectious disease, R will decrease below unit due to exhaustion of susceptible individuals, at the expense of a tremendous amount of infected and dead individuals, collapsing not only the health system but the economy as well.