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Occurrence of variants of SARS-CoV-2 in the Americas: Preliminary information (11 January 2021)

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Through this document, the Pan American Health Organization / World Health Organization (PAHO/WHO) communicates to the Member States preliminary information on the detection in the Americas of two variants of interest of SARS-CoV-2 that have been associated with increased transmission in the United Kingdom and in the Republic of South Africa.

PAHO / WHO recommends that Member States continue with the sequencing of samples according to the guidelines of the regional genomic surveillance network and monitor sudden changes in the incidence of COVID-19, which occur in light of public health measures and of social distancing implemented and fulfilled by the population.


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 nominated 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.

Since the initial identification of SARS-CoV-2 to date, more than 280,000 complete genomic sequences have been shared globally through publicly accessible databases. Having the ability 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 justifies and urges expanding sequencing capacity; however, challenges for widespread implementation persist (sufficient trained personnel, availability of equipment, reagents, and bioinformatics infrastructure, assurance of data quality, and capacities for its interpretation and use). Currently, sequencing capacity and data are not uniformly distributed worldwide, with a skewed representation of the SARS-CoV-2 GSD from high-income countries. This bias must be considered when evaluating the presence or absence of a particular variant in a place and its relative frequency.