Delta Plus variant major challenge, warns expert :Senior biotechnologist in Siliguri says new variant could evade vaccines

SNS, SILIGURI, 22 June : A day after India set a world record by vaccinating more than 6.16 lakh people against Covid-19 as part of a mega inoculation campaign launched to coincide with International Yoga Day, experts in north Bengal today warned that the country's fight against coronavirus might face a daunting challenge in the coming months as the newly detected Delta Plus variant found in Kerala, Maharashtra and Madhya Pradesh might soon grow to evade Covid-19 vaccines and even immunity gained from previous infections.

According to a senior professor of the Department of Biotechnology, University of North Bengal, Dr Ranadhir Chakraborty, the new variant was resistant to the monoclonal antibody cocktail treatment for Covid-19 recently authorised in India.

"The highly transmissible Delta variant of SARS-CoV-2 has mutated further to form the 'Delta plus' or 'AY.1' variant. The new Delta plus variant, which is also known as the B.1.617.2.1 variant, has been formed due to a mutation in the Delta or B.1.617.2 variant, first identified in India and one of the drivers of the deadly second wave. The AY.1 variant is characterised by the acquisition of K417N mutation, in which Lysine has changed into Asparagine. The variant was first discovered in the Beta variant in South Africa," said Dr Chakraborty, who was part of an international team, which mapped a total of 71,703 genomes of the coronavirus till August 2020.

Referring to initial reports, the veteran microbiologist said the new Delta plus variant had shown signs of resistance against the monoclonal antibody cocktail treatment, which had been found to be a life-saving treatment in high-risk groups with mild to moderate Covid-19 symptoms. "To fight a viral infection, our bodies create proteins known as antibodies. Monoclonal antibodies are artificial antibodies that mimic the activity of our immune systems. They are produced through a process that involves extracting specific antibodies from human blood and then cloning them," he said.

"These monoclonal antibodies are designed to target a virus or a specific part of one-for instance, REGEN-COV2 is a cocktail of two monoclonal antibodies, namely Casirivimab and Imdevimab, which are developed to target the SARS-CoV-2 spike protein. The two monoclonal antibodies bind non-competitively in the non-overlapping receptor binding domain of the spike protein, blocking its ability to infect healthy cells," he added.

Researches during the pandemic had increased optimism in monoclonal antibodies' ability to help reduce the risk of hospitalization, especially in high-risk patients such as those suffering from severe diabetes, renal and immunosuppressive diseases as well as those surviving on immunosuppressive drugs.

According to Dr Chakraborty, some monoclonaI antibodies had shown the ability to retain activity against multiplevariants of the virus. "But it is sad to note that the monoclonal antibody treatment may not be effective any more as it has been found that Casirivimab and Imdevimab were unable to bind non-competitively with the spike protein of the new AY.I variant," he regretted.

He added that the variant was not new and till June7 this year, a total of 63 genomes of the Delta plus variant had been collected by GISAID, the 2008-established global science initiative and primary source that provides open-access to genomic data of influenza viruses and the coronavirus responsible for the Covid-19 pandemic.

"The variant was first seen in Europe in March this year. Till June 7, six, nine,12 and 14 cases of the variant were discovered in India, Poland, Portugal and USA respectively It was, however, brought into the public domain only on lune 13. Mutations are nothing new. While mapping genomes of the coronavirus till August 2020, we had detected as many as 375 mutations in the receptor binding domain of the virus, in which 208 were highly significant missense mutations," he said.

The senior biotechnologist cautioned that the new variant could work havoc on the country as it could be more transmissible than others. "The variant has a higher potential to infect human airway cells, which is believed to be more congenial and conducive to its growth. As a result, the amount of the virus discharged from the airways into the surrounding atmosphere could be much higher," he pointed out.

The ace researcher feared that the new variant might be able to bypass immunity provided by both vaccine and earlier infection. "Immediate and extensive studies should be conducted to ascertain if the Delta plus variant was capable of evading both immunities from Covid vaccination as well as immunity generated by earlier infections. The health authorities must take urgent and adequate measures," he said.