VARIANTS OF CONCERN

VARIANTS OF CONCERN

Subject: Science & tech

Context: In many countries, including India, the VOC, by virtue of increased transmissibility, have kicked off new wave(s) of epidemic transmission.

Concept:

• The term variant of concern (VOC) is a category used during the initial assessment of a newly emerged variant of a virus. Before this, an emerging variant may have been labeled a “variant of interest”.
• During or after fuller assessment as a “variant of concern” the variant is typically assigned to a lineage in the PANGOLIN nomenclature system and to clades in the Nextstrain and GISAID systems.
• There are three different schemes of nomenclature of SARS-CoV-2 variants.
• The widely used one is the ‘Phylogenetic Assignment of Global Outbreak Lineages’ (PANGOLIN) that uses a hierarchical system based on genetic relatedness – an invaluable tool for genomic surveillance.
• For convenience, the three most frequent ones are named by their geography of origin — ‘U.K. variant’ for B.1.1.7; ‘South Africa variant’ for B.1.351; and ‘Brazil variant’ for P.1.
• Variants in India include the so-called double mutant B.1.617 spreading in Maharashtra and B.1.618 spreading in West Bengal.
• During the pandemic, the virus Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was observed to mutate, with certain combinations of specific point mutations proving to be more concerning than others.
• This was principally for reasons of transmissibility and virulence, and also with regard to the possible emergence of escape mutations.