The Delta variant (B.1.617.2) of SARS-CoV-2 has mutated further. Identified as “Delta plus” or “AY.1” variant, it is said to be resistant to the monoclonal antibody cocktail treatment for Covid-19 recently authorised in India. According to reports, Delta plus has been found to be present in six genomes from India as of June 7.
Health experts have said that there is no immediate cause for concern in India as its incidence here is still low and two doses of vaccines, putting up masks and implementing Covid appropriate norms can help check its infection.
However, given the snail’s pace of vaccination drive owing to jab shortage and poor implementation of social norms for Covid-19, the authorities may find it difficult to combat its spread in the coming days.
“One of the emerging variants is B.1.617.2.1 also known as AY.1 characterized by the acquisition of K417N mutation,” Vinod Scaria, clinician and scientist at Delhi’s CSIR-Institute of Genomics and Integrative Biology (IGIB), tweeted on Sunday. The mutation, he pointed out, is in the spike protein of SARS-COV-2, which helps the virus enter and infect the human cells.
At least 63 genomes of Delta (B.1.617.2) with the new K417N mutation have been identified so far on the global science initiative GISAID, according to Public Health England report. In its latest report on coronavirus variants, updated till last Friday, the health agency said Delta plus was present in six genomes from India as of June 7.
“The variant frequency for K417N is not much in India at this point in time. The sequences are mostly from Europe, Asia and America,” Scaria twitted. The earliest sequence of this genome was found in Europe in late March this year.
Stating that the travel histories for the variant were yet not readily available to make assumptions, “evidence suggests that it is resistance to monoclonal antibodies Casirivimab and Imdevimab”.
Monoclonal antibodies are laboratory-made proteins that mimic the immune system’s ability to fight off viruses. Of late, some monoclonal antibodies have been specifically designed to target the spike protein of the Covid virus -- they do not let the virus attach itself and enter into the human cells.
Casirivimab and Imdevimab are monoclonal antibodies that are specifically directed against the spike protein of SARSCoV-2, and designed to block the virus’ attachment and entry into human cells, according to reports.
Scaria also suggested the mutation may be associated with the ability to escape the immune response against the virus. “There is no cause of concern due to the new variant in India as of now,” added Anurag Agrawal, the director of CSIR-IGIB said.
He said that the blood plasma from many fully vaccinated individuals will have to be tested against this variant to determine whether it shows any significant immune escape.
Agrawal further said SARS-CoV-2 has a nearly constant rate of acquiring genetic variants, and each variant has acquired additional variants in a stepwise fashion.
“Understanding this continued evolution is of great importance in mapping the evolutionary landscape of emerging variants. Largely the virus has tried to optimise for transmission and immune escape by step-wise acquisition of new mutations,” he added.
