Context:
The World Health Organisation classified a coronavirus variant first identified in India as a “global variant of concern”.
This variant called B.1.617 was classified as a variant under investigation (VUI) by authorities in the UK earlier in May 2021 and it has already spread to more than 17 countries.
Relevance:
GS-III: Science and Technology
Dimensions of the Article:
- What is a variant and how do they emerge?
- How are variants of the coronavirus being classified?
- Is B.1.617 the reason for the current surge in India?
What is a variant and how do they emerge?
- Variants of a virus have one or more mutations that differentiate it from the other variants that are in circulation.
- While most mutations are deleterious for the virus, some make it easier for the virus to survive.
- The SARS-CoV-2 virus is evolving fast because of the scale at which it has infected people around the world. High levels of circulation mean it is easier for the virus to change as it is able to replicate faster.
How are variants of the coronavirus being classified?
Variants Under Investigation (VUI)
- Public Health England (PHE) says that if the variants of SARS-CoV-2 are considered to have epidemiological, immunological or pathogenic properties, they are raised for formal investigation.
- At this point, the variants emerging from the B.1.617 lineage are designated as VUI.
US Centers for Disease Control and Prevention (CDC) Classification
The US Centers for Disease Control and Prevention (CDC) classifies variants into three categories:
- Variant of Interest (VOI): A variant with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity. (B.1.617 variant with two mutations, referred to as E484Q and L452R).
- Variant of Concern (VOC): A variant for which there is evidence of an increase in transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures. (B.1.1.7 (UK variant), B.1.351 (South Africa Variant), P.1 (Brazil Variant), B.1.427, and B.1.429 variants).
- Variant of High Consequence (VHC): A variant of high consequence has clear evidence that prevention measures or medical countermeasures have significantly reduced effectiveness relative to previously circulating variants. (No examples so far).
Phylogenetic Assignment of Global Outbreak Lineages (PANGOLIN) Nomenclature
- Phylogenetic Assignment of Global Outbreak Lineages (PANGOLIN) was developed to implement the dynamic nomenclature of SARS-CoV-2 lineages, known as the Pango nomenclature.
- It uses a hierarchical system based on genetic relatedness – an invaluable tool for genomic surveillance.
- It uses alphabets (A, B, C, P) and numerals starting with 1. Variant lineages are at the emerging edge of the pandemic in different geographies. Lineage B is the most prolific.
Is B.1.617 the reason for the current surge in India?
- Recently, during the second wave of Covid-19 the Indian government said that this variant also called the “double mutant variant” could be linked to a surge in the cases of coronavirus seen in some states. Even so, the government said that the link was not “fully established”.
- Earlier, India’s Health Ministry had said that a new “double mutant variant” of the coronavirus had been detected in addition to many other strains or variants of concern (VOCs) found in 18 states in the country.
- B.1.617 was first designated as a VUI on April 1 by the UK health authorities who requested India to send samples of the B.1.617 strain to carry out wider studies on it and determine how effective existing vaccines are against it.
-Source: The Hindu, Indian Express
