Using genomic data from across Brazil and neighboring Paraguay, a multi-institute team including scientists from the Universidade Federal de Minas Gerais and the University of São Paulo have generated insights into the emergence and spread of SARS-CoV-2 in Brazil. In the study, which appears in Nature Microbiology this week, the researchers analyzed 17,135 near-complete genomes sampled from 27 Brazilian states and Paraguay up until September 2021. They detect co-circulation of multiple viral lineages linked to multiple importations, primarily from Europe, between March and November 2020. The researchers also find large, local transmission clusters within the country after November 2020, likely due to the absence of effective restriction measures, as Brazil transitioned from a viral importer to a viral exporter to Paraguay and elsewhere. "Our data further suggest that the lifting of national and international travel restrictions at specific times during the Brazilian epidemic was probably responsible for both introduction of SARS-CoV-2 from abroad and within-country transmission," the study's authors write. The study "highlights the utility of SARS-CoV-2 genome sequencing for comprehensive country-wide studies of the epidemiology and spread of emerging viral strains," they add.