EVOLUTION OF SARS-COV-2 GAMMA VARIANT DURING THE SECOND WAVE OF THE COVID-19 PANDEMIC IN ARGENTINA

ZAMBRANA MONTAÑO R; NABAES JODAR M; GOYA S; ACUÑA D; ACEVEDO RM; AMADIO A; BRUSES B; CEBALLOS S; DEBAT H; EBERHARDT MF; FERNANDEZ A; FERNANDEZ F; FORMICHELLI L; GALLEGO F; GRAMUNDI I; IRAZOQUI M; KONIG G; LORENZINI CAMPOS M; LUCERO H; MARQUEZ N; MAZZEO M; MUSSIN J; NARDI C; ORIA GI; OUSSET J; PIANCIOLA L; PINTOS C; PUEBLA A; RASTELLINI C; ROJAS E; VALINOTTO L; ZIEHN C; PROYECTO PAIS; TORRES, CAROLINA (ULTIMA AUTORIA COMPARTIDA, AUTOR PARA CORRESPONDENCIA COMPARTIDO); VIEGAS M (ULTIMA AUTORIA COMPARTIDA, AUTOR PARA CORRESPONDENCIA COMPARTIDO)

Congreso; 3rd Women in Bioinformatics & Data Science LA Conference; 2022

COVID-19 epidemic in Argentina has been characterized by four waves of infections. The second one, which started in March 2021 and peaked around May 2021, had the highest death rate recorded in the entire pandemic in the country. This wave was associated with the introduction and rapid spread of the variants with concerning characteristics to public health, including the Variant of Concern (VOC) named Gamma (lineage P.1 and its sublineages), a highly transmissible variant with immune evasion ability.This study aimed to understand the evolution process and spread of the Gamma variant in Argentina.We analyzed 625 SARS-CoV-2 whole-genome sequences belonging to Gamma variant from individuals diagnosed from February to December 2021, obtained with Oxford Nanopore or Illumina platforms, in the context of the molecular surveillance implemented by PAIS Project. Phylogenetic analysis was performed (Maximum Likelihood method, IQ-TREE v2.1 software) to identify introduction events and to study their diversification process.Argentinean sequences were assigned to lineage P.1 (45.4%) and the main sublineages found were P.1.15 (34.1%) and P.1.2 (17.8%), followed by P.1.14 (1.9%), P.1.17 (0.9%) and P.1.13 (0.6%).Analyses showed several introductions of Gamma variant to the country, with the most related sequences being from Brazil, Chile and the USA. Three large groups containing Argentinean sequences from north to south of the country were observed for lineage P.1 and one for sublineage P.1.15, which suggests a wide local transmission and diversification of common transmission chains. For sublineage P.1.12, clusters included sequences from a few Argentinean provinces, which suggests a more limited distribution. In conclusion, Gamma was the main variant in the second wave of COVID-19 in Argentina, originated from several introductions and showing a wide distribution across the country, revealing the impact of the regional circulation of SARS-CoV-2 variants on the epidemiology of the country in the second wave.