Biological characteristics of SARS-CoV-2 variants of epidemiological interest and their impact on vaccine efficacy and effectiveness.

Abstract

Since December 2020, the detection of emerging viral variants of SARS-CoV-2 has attracted the attention of the scientific community and governments at the national and international levels. Some versions of the virus characterized by genetic/evolutionary, epidemiological and/or phenotypic changes have been classified by the WHO as alerts for further monitoring, variants of interest (VOI), or variants of concern (VOC). At the international level, the current situation of variants reflects the sustained advance of the VOC Delta, driving new waves in much of the globe. On the other hand, South America, which exhibits an exceptional landscape of variants dominated by the regionally emerged Gamma (VOC) and Lambda (VOI) begins to face Delta's entry into a dynamic equilibrium of tension between viral evolution, immunity of the population associated with the second wave, and the asymmetry of vaccination campaigns and regional health policies. In this review, we present an update of the latest advances regarding the study of these variants, their potential impact on the epidemiological dynamics and vaccine effectiveness, with a special focus on the Latin American situation of the COVID-19 pandemic, in the second half of 2021.