The Lambda Variant in Argentina: Analyzing the Evolution and Spread of SARS-CoV-2 Lineage C.37

NABAES JODAR, MERCEDES SOLEDAD; TORRES, CAROLINA; MOJSIEJCZUK, LAURA; ACUÑA, DOLORES; VALINOTTO, LAURA ELENA; GOYA, STEPHANIE; CAVATORTA, ANA

Viruses

MDPI

Año: 2023 vol. 15

The second wave of COVID-19 occurred in South America in early 2021 and was mainlydriven by Gamma and Lambda variants. In this study, we aimed to describe the emergence andlocal genomic diversity of the SARS-CoV-2 Lambda variant in Argentina, from its initial entry intothe country until its detection ceased. Molecular surveillance was conducted on 9356 samples fromArgentina between October 2020 and April 2022, and sequencing, phylogenetic, and phylogeographicanalyses were performed. Our findings revealed that the Lambda variant was first detected inArgentina in January 2021 and steadily increased in frequency until it peaked in April 2021, with continueddetection throughout the year. Phylodynamic analyses showed that at least 18 introductionsof the Lambda variant into the country occurred, with nine of them having evidence of onward localtransmission. The spatial—temporal reconstruction showed that Argentine clades were associatedwith Lambda sequences from Latin America and suggested an initial diversification in the MetropolitanArea of Buenos Aires before spreading to other regions in Argentina. Genetic analyses of genomesequences allowed us to describe the mutational patterns of the Argentine Lambda sequences anddetect the emergence of rare mutations in an immunocompromised patient. Our study highlights theimportance of genomic surveillance in identifying the introduction and geographical distribution ofthe SARS-CoV-2 Lambda variant, as well as in monitoring the emergence of mutations that could beinvolved in the evolutionary leaps that characterize variants of concern.