B.1.617 strain

Description

GS PAPER II: Issues Relating to Development and Management of Social Sector/Services relating to Health, Education, Human Resources.

Context: WHO classifies India variant as being of global concern.

What does it mean?

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.
This variant called B.1.617 was classified as a variant under investigation (VUI) by authorities in the UK earlier in May.
It has already spread to more than 17 countries and several countries have put travel restrictions for passengers coming from India as a result of the surge in cases here.

How does the WHO define a variant of concern?

The WHO says that a variant of interest (VOI) becomes a variant of concern (VOC) if, through a comparative assessment, it has been demonstrated to be associated with
- increase in transmissibility or detrimental change in COVID-19 epidemiology,
- increase in virulence or change in clinical disease presentation or
- a decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.
Alternatively, a variant may be classified as a VOC by the WHO in consultation with the WHO SARS-CoV-2 Virus Evolution Working Group.

Is B.1.617 the reason for the current surge in India?

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.
This admission was a change in the Centre’s previous stance when it said that the strain was not identified in enough samples to establish a sufficient link to the current surge.

How do variants of a virus emerge and why?

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.
Essentially, the goal of the virus is to reach a stage where it can cohabitate with humans because it needs a host to survive.
This means, any virus is likely to become less severe as it keeps evolving, but in this process it can attain some mutations that may be able to escape the body’s immune response or become more transmissible.
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.
The B.1.617 variant of the virus has two mutations referred to as E484Q and L452R.
Both are separately found in many other coronavirus variants, but they have been reported together for the first time in India.
The L452R mutation has been found in some other VOIs such as B.1.427/ B.1.429, which are believed to be more transmissible and may be able to override neutralising antibodies.