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Epidemiological update: Occurrence of variants of SARS-CoV-2 in the Americas (20 January 2021)

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Introduction

The appearance of mutations is a natural and expected event within the evolution of the virus. Since the initial genomic characterization of SARS-CoV-2, the virus has been divided into different genetic groups or clades. In fact, some specific mutations define the viral genetic groups (also called lineages) that are currently circulating globally (Table 1 and Figure 1). Due to various microevolution processes and selection pressures, some additional mutations may appear, generating differences within each genetic group (called variants). It is important to mention that the name of the clade, lineage, variant, etc., are arbitrary and do not correspond to an official taxonomic hierarchy.

With the information available to date, most of the changes in SARS-CoV-2 have had little or no impact on how it is transmitted or the severity of the disease it causes.

Since the initial identification of SARS-CoV-2 to date, more than 387,500 complete genomic sequences have been shared globally through publicly accessible databases. The capacity to monitor the data in near real time has a direct impact on the public health response to the COVID-19 pandemic.

The growing understanding of how genomic sequencing data (GSD) can contribute to improving public health, supports and encourages expanding sequencing capacity; however, challenges for widespread implementation persist (e.g., having sufficient trained personnel, availability of equipment, reagents and bioinformatics infrastructure, data quality assurance, and capacities for its interpretation and use). Currently, sequencing capacity and data are not uniformly distributed globally, with a skewed representation of the SARS-CoV-2 GSD from highincome countries. This bias must be considered when evaluating the presence or absence of a particular variant in a place and its relative frequency.