In December 2020, COVID-19 Genonics UK (COG-UK) identified a new and potentially more infectious variant of the novel coronavirus. (COG-UK is a group of genomic experts that studies genome sequencing data from the UK and is the largest contributor to the global COVID-19 database GISAID). The new strain of the virus was first spotted in samples from Kent and London. It reached UK through two travellers from South Africa. The South Africa’s health department had made an announcement about the new genetic mutation of the virus and its role in the recent surge in infections there. This mutated strain of the virus is up to 70 per cent more transmissible. Therefore, a swift decision was taken by the British government to cut off the capital and its surrounding counties from the rest of England.
The Mutated Virus
This mutated virus or a distinct phylogenetic cluster or lineage of SARS-CoV-2 (named B.1.1.7) has a changed genetic sequence, i.e., rearranged molecules, which generally occurs when a virus makes a mistake in making copies of itself. The variant is seen as a result of multiple mutations in the spike protein and other genomic regions of the novel coronavirus, which is an RNA virus. It has been identified as N501Y in an area of the spike protein that binds to a key protein in the human cell, the ACE2 receptor, thus helping entry into susceptible cells.
Mutations in Virus
The genetic material or genome of SARS-CoV-2 is an RNA. Among the RNA viruses, those with the largest genome are the coronaviruses. When genomes of any sort replicate, whether DNA or RNA, human or virus, there are random errors (or mutations). Unlike higher organisms, viruses, especially the RNA ones, lack the ability to correct these errors. Most mutations are harmful but only the mutations that offer some selective advantage result in the evolution of new variants of the virus. Selectivity in the process of evolution demands, in the case of a virus, that the virus be able to infect better and multiply or escape the action of immunity in the host. The virus takes the route of high rates of multiplication; for example, each coronavirus-infected cell produces about 1,000 new virus particles in less than 12 hours.
As per the COG-UK, there were around 4,000 mutations in the spike protein of SARS-CoV-2. A strain that spreads easily becomes dominant—earlier D614G was dominant, strain 20A originated in Spanish farm workers, and another strain EUI rapidly spread across Europe in the summer of 2020. It cannot be predicted with certainity whether any given mutation is important, in terms of becoming dominant, when it first emerges.
India’s Response
As several returnees from the UK to India have been found to be infected with the new strain, it was decided to identify and locate people who had travelled from the UK to test them for the virus. Viral strains collected from the blood of infected people are also being studied.
Since the risk of Covid-19 transmission increased significantly with the introduction of the new viral strain, India suspended international flights till January 31. Some states like Maharashtra, Karnataka, Rajasthan, Tamil Nadu, and Uttarakhand renewed partial curfew in the wake of the new strain.
Concerns regarding New Variant
A widespread concern regarding the new mutant is that it may prevent currently used RT-PCR tests from detecting the virus or that it may evade vaccines under development. However, currently there is no evidence to suggest that the new variant can cause a more severe disease or that the vaccine would not protect people against it.
After UK, a new variant of coronavirus, P681H, was identified in Nigeria, as per the head of the Africa Centre for Disease Control and Prevention, John Nkengasing. It is a separate lineage from the variant found in South Africa and UK.