Impact of SARS-CoV-2 Gamma lineage introduction and COVID-19 vaccination on the epidemiological landscape of a Brazilian city

Here, we evaluated the introductions of SARS-CoV-2 lineages in a Brazilian city with the third-highest number of confirmed COVID-19 cases in the state of São Paulo. Our analyses revealed several SARS-CoV-2 lineages first detected in the city, but after the introduction of the Gamma lineage, the majority of them were replaced by this variant that became the most common. At the same time, there was an increase in the number of infections, severe disease cases, and deaths, mainly in individuals under 70 years old, the age group that was not fully vaccinated at the time. Our findings further support the evidence that vaccination effectively decreases SARS-CoV-2 spread and transmission.