Figure 1.

Replacement of the Gamma by the Delta variant in Brazil. (A) Dynamics of the SARS-CoV-2 epidemic in Brazil showing the number of daily COVID-19 deaths and the progression in the proportion of circulating variants in the country over time, with the rapid replacement of the Gamma by the Delta variant. (B–C) The modelled proportion of SARS-CoV-2 variants over time in Brazil in a linear and in a logarithmic scale (respectively), showing that Gamma became the dominant variant in Brazil by the beginning of 2021 and was rapidly outcompeted by Delta from June 2021. Model fits are based on a multinomial logistic regression. The size of the dots corresponds to the weekly sample size of SARS-CoV-2 genomes (independently of variants, such that each week will have the same point size across all variant curves). (D) Prevalence maps following the progression in the monthly average of a daily number of cases and proportions of each variant (Alpha, Zeta, Gamma, and Delta) per region (North, Northeast, Midwest, Southeast, and South) in Brazil from October 2020 to October 2021. The scale 0–1 used represents the time-relative prevalence of each variant calculated independently of all the others (i.e. variant prevalence divided by its maximum across time). It shows the spatio-temporal evolution of each variant’s spread.