Scientists have found a new lineage of the SARS-CoV-2 virus named 'B.1.618' in India, which is predominantly circulating in West Bengal. This is the second lineage to be identified from the country as per Vinod Scaria, a researcher at the Council of Scientific and Industrial Research's Institute of Genomics and Integrative Biology (CSIR-IGIB) in New Delhi.
According to a Twitter thread by Scaria, "E484K is a major immune escape variant -- also found in a number of emerging lineages across the world. E484K can escape multiple mAbs as well as panels of convalescent plasma." This means that the infection through this variant makes plasma therapy as redundant as an investigational treatment.
B.1.618 - a new lineage of SARS-CoV-2 predominantly found in India and characterized by a distinct set of genetic variants including E484K , a major immune escape variant. pic.twitter.com/dtfQJp2S2B- Vinod Scaria (@vinodscaria) April 20, 2021
"While E484K is in the Receptor Binding Domain, Y145 and H146 are not part of the residues interacting with the Human ACE2 receptor. The structural impact of the 2AA deletion causes to spike protein is yet to be understood completely," added Scaria.
The earliest sequence of this virus' lineage was isolated on October 10, 2020, from a patient in West Bengal. While the lineage of the SARS-CoV-2 virus is mainly found in India, variants have also been found in the US, Switzerland, Singapore and Finland. The variant was first found in a sample outside of India on April 22, 2020.
The first new mutant variant 'B.1.617', also known as the 'double mutant' virus, was found in over 60 per cent of cases sampled for genome sequencing in Maharashtra.
The new variant, B.1.618 is characterised by a distinct set of genetic variants including E484K. It is also called a major immune escape variant, as it can escape immunity even if a person has contracted the virus before and can produce antibodies against it.
Scaria said, "There are many unknowns about this lineage at this moment, including its capability to cause reinfections as well as vaccine breakthrough infections. Additional experimental data is also required to assess the efficacy of vaccines against this variant."
In India, at least 129 of the 130 B.1.618 sequences were found in samples from West Bengal. According to outbreak.info's analysis, India currently has 62.5 per cent of the B.1.618 variants reported worldwide.
"At this moment, there is no conclusive evidence that the lineage drives the epidemic in West Bengal, apart from the fact that the numbers and proportions have been significantly increasing in recent months. More focused epidemiological investigations would address these questions," he added.
Data submitted from India to GISAID shows B.1.618 - at 12 per cent - is the third most common SARS-CoV-2 variant sequenced in the last 60 days. The B.1.617 - at 28 per cent - is the most common variant among sequences, followed by the UK variant B.1.1.7, showed India Mutation Report by Scripps Research, citing the GISAID data.