Evaluating the impacts of relaxation and mutation in the SARS-CoV-2 on the COVID-19 epidemic based on a mathematical model: a case study of São Paulo State (Brazil)

Abstract

At the beginning of 2020, SARS-CoV-2 spread to all continents, and many countries adopted quarantine to flatten the COVID-19 outbreak, resulting in the containment of transmission. However, the persistent transmission of SARS-CoV-2, an RNA virus, resulted in the appearance of mutations in the original virus. The appearance of more virulent mutations in different regions of the world resulted in an increased number of severe COVID-19 cases. A mathematical model based on the COVID-19 natural history encompassing the mutations was applied to evaluate the SARS-CoV-2 epidemic. The model parameters were fitted against the observed data from São Paulo State (Brazil) considering quarantine, relaxation, and mutation. The estimated data from São Paulo State showed that the original SARS-CoV-2 transmission better explained the COVID-19 epidemic during the quarantine. However, the increased number of fatalities beyond that predicted by the relaxation indicated the occurrence of mutations. Hence, the relaxation in association with the transmission of a more virulent SARS-CoV-2 better estimated the COVID-19 epidemic from February 26, 2020, to June 15, 2021

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“…Therefore, it is necessary to crime-protecting at least 99.8% of the population to eliminate the corruption. Interestingly, considering R 0 = 7.63, the Covid-19 epidemic's first wave fades out when 99.4% of individuals are immunized [31].…”

“…The Covid-19 pandemic shed light to show how an invisible enemy, the SARS-CoV-2, must be faced: individuals' rights were suppressed not for days, but months [31]. Indeed, the quarantine associated with individual (sanitization of hands, use of face masks) and collective (social distancing) measures contributed to controlling the pandemic.…”

“…The continuous and insistently propagation of the use of non-efficient drugs as early treatment (encouraging anti-quarantine movement and non-use of individual and collective protections by a relatively significant proportion of the population), resulted in a delay in the mass immunization. As a consequence, a more virulent mutation of SARS-CoV-2 appeared [31].…”

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