21st June, 2021 Prelims


  • 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?

  • A small number of sequences of Delta (B.1.617.2) have recently been designated as lineage AY.1 (B.1.617.2.1), a sublineage of Delta.
  • The formation of the Delta plus variant of the SARS-CoV-2 is a result of K417N mutation.
  • This is the mutation of the spike protein which causes the virus to enter and infect human cells.
  • Delta plus variant has been identified in six genomes from India.
  • 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 sequences are mostly from Europe, Asia and America.
  • 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.


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.


Transmissibility of Delta plus variant

  • 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.


Read about Monoclonal antibodies here: