India’s double mutant COVID strain is ‘variant of global concern’. This variant called B.1.617 was classified as a variant under investigation (VUI) by authorities in the UK earlier in May.
The variant 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.
The WHO says “that a variant of interest (VOI) becomes a variant of concern (VOC) if, through a comparative assessment, it has been proved to be associated with increase in transmissibility or detrimental change 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.”
The variant 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.
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 movement mean it is easier for the virus to change as it is able to replicate faster.
The US Centers for Disease Control and Prevention (CDC), on the other hand classifies variants into three categories– variant of interest (VOI), variant of concern (VOC) and variant of high consequence. In the US, the B.1.526, B.1.526.1, B.1.525 (previously designated UK1188 and first identified in the UK), and P.2 (identified first in Brazil) variants. On the other hand, the B.1.1.7, B.1.351, P.1, B.1.427, and B.1.429 variants circulating in the US are classified as variants of concern.