Recently, the Ministry of Health has reported that a new double mutant Variant has been detected in 18 different states of the country, in addition to many other strains or variants of the coronavirus. In this context, it is important to understand how these variants are classified and the different terminologies associated with them.
What are Virus Variants?
Variants of the virus have one or more mutations that differentiate them from other popular variants. Most mutations prove to be harmful to the virus, while some mutations are beneficial for the virus, which make it easier to survive.
The coronavirus is developing rapidly due to which it is infecting people globally. The high level of circulation or spread of the virus means that the virus has an easy and rapid rate of mutation, due to which it has the ability to multiply its number.
The original pandemic virus that hit the world first was Wu.Hu.1 popularly called the Wuhan virus. In a few months, its D614G variant emerged globally.
How these variants are classified?
The variants are classified into 3 categories by the American Centre for Disease Control and Prevention.
- Variants of interest (VOI):
It is a variant with specific ‘genetic markers’ that alters the ‘receptor binding’, reducing the effects of infection by antibodies generated during a previous infection or vaccination, reducing the clinical impact and potential treatment. Relating to transmitting infection or increasing the severity of the disease.An example of VOI is the B.1.617 variant of the virus, which has two mutations, called E484Q and L452R. This variant is classified as ‘Variant of Interest (VOI) by the World Health Organization (WHO).
Both of these mutations are found separately in many coronavirus variants, but for the first time in India, these two have been seen together.
- Variants of Concern (VOC):
This variant of the virus results in an increase in transmission, cause more severe illness.This marks a significant decrease in antibodies produced during a previous infection or vaccination. This also causes a decrease in the effectiveness of treatment or vaccine.
B.1.1.7 (UK variant), B.1.351 (South Africa variant), P.1 (Brazil variant), B.1.427 and B.1.429 variants found in the US are classified as VOCs.
- More serious variants:
More severe variants confirm that prevention measures or medical countermeasures have significantly reduced the relative effectiveness of already prevalent variants.The CDC has yet not found any evidence of the proliferation of ‘more severe variants’ in the US.
- Variants Under Investigation (VUI):
Public Health England states that if properties likewider transmission or affecting immunity are found in variants of SARS-CoV-2, then it can be formally investigated.
The B.1.617 variant has been designated as VUI for this task.
How names are given to these variants?
Phylogenetic Assignment of Global Outbreak Lineages or PANGOLIN was developed to implement the nomenclature of the lineage of the SARS-CoV-2 lineages. This nomenclature is known as the ‘Pango Nomenclature’.
It uses a hierarchical system based on heredity as an invaluable tool of genomic monitoring. It uses letters (ABCP) that begin with 1 number. Variant lineages of the pandemic are found in different geographical regions. Notably, Lineage ‘B’ is the most growing lineage.
What are the concerns associated with these variants?
Many countries including India have observed new waves of pandemic transmission due to the proliferation of such variants.
In these variants, the UK variant is more dangerous in terms of severity.Whereas, the variants of South Africa and Brazil are not more fatal.
Besides, the use of antigens made from the D614G variant used in vaccination, which is used in many vaccines.Low levels of vaccine effects have been observed in South African and lower Brazilian variants. Therefore, despite the earlier D614G vaccination, there is a risk of re-infection.
Currently, the efficacy of vaccines may be lower than their potential as determined in three-phase trials because VOC proliferation was not widespread then. However, mRNA vaccines still provide good protection from the virus.