The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delta variant is diverse, with more than 120 sublineages within the Pango lineages. With more than 157 million doses of the anti-SARS-CoV-2 vaccine administered and approximately 124 million people fully vaccinated, Brazil is one of the most vaccinated nations globally.
This high vaccination rate may also help in the selection of novel SARS-CoV-2 lineages and sublineages because of the accumulation of viral mutations that lead to viral fitness. Despite the preexisting gamma variant of concern (VOC) being fully replaced by the delta VOC in Brazil, no exponential growth of the new infections has been observed, probably due to the good vaccination rate.
