The Delta variant of SARS-CoV-2, also known as B.1.617.3 strain, has been pinned as the primary driver of the devastating second wave of the COVID-19 pandemic in India. Now, the Delta variant of the virus has further mutated into the Delta plus or 'AY.1' variant. According to initial reports, this new Delta plus variant has shown signs of resistance against the monoclonal antibody cocktail treatment which was recently approved by the Central Drugs Standard Control Organisation (CDSCO).
What is Delta plus variant?
The formation of the Delta plus variant of the SARS-CoV-2 is a result of K417N mutation. This the mutation of the spike protein which causes the virus to enter and infect human cells.
Bani Jolly, a scientist who specialises in genomic sequencing, wrote about the new variant on Twitter, "A small number of sequences of Delta (B.1.617.2) having spike mutation K417N can be found on GISAID. As of today, these sequences have been identified in genomes from 10 countries."
"The sequences have recently been designated as lineage AY.1 (B.1.617.2.1), a sublineage of Delta, due to concerns about K417N being one of the mutations found in the Beta variant (B.1.351)," Jolly added.
Public Health England has explained that the Delta plus variant has been identified in six genomes from India till June 7. Till now, the UK health agency has determined the presence of a total of 63 genomes of the Delta variant of SARS-CoV-2 that have the K417N mutation in them.
Delta plus variant not prominent in India
Scientists have not sounded the alarm as the presence of the Delta plus variant is still low in India. "The variant frequency for K417N is not much in India at this point in time. The sequences are mostly from Europe, Asia and America," said Vinod Scaria, a scientist at Delhi-based CSIR-Institute of Genomics and Integrative Biology (IGIB). "Travel histories for the Delta plus variant are not readily available," Scaria added.
Apart from India, the sequences have come from a number of countries across the world. These include - USA, Canada, United Kingdom, Russia, Japan, Portugal, Poland, Turkey, Nepal and Switzerland, according to Outbreak Info.
"Looking at the large (T95I) cluster, it seems like AY.1 has arisen independently a number of times and could be more prevalent than observed in countries with limited genomic surveillance," added Bani Jolly.
Delta plus variant resistant to monoclonal antibody treatment
Scientists have explained that the mutation in the Delta variant of SARS-CoV-2 was resisting the monoclonal antibody treatment for COVID-19. "One important point to consider regarding K417N is evidence suggesting resistance to monoclonal antibodies Casirivimab and Imdevimab. The antibody cocktail has accidentally received an EUA from the Drug Controller General in India," noted Vinod Scaria.
Transmissibility of Delta plus variant
Vineeta Bal, an immunologist who is a guest faculty at Pune's Indian Institute of Science Education and Research, has stated that the Delta plus variant's resistance to monoclonal antibody treatment does not determine whether the new variant has a higher transmissibility rate or causes more severe infection.
"How transmissible this new variant is will be a crucial factor to determine its rapid spread or otherwise," Vineeta Bai. "Thus, in individuals catching infection with the new variant, it may not be a matter worth worrying," she added, according to PTI.(Edited by Mohammad Haaris Beg)
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