Bengaluru: The Union health ministry this week confirmed the presence of a coronavirus variant in Maharashtra carrying two genetic mutations. The ministry is calling it a ‘double mutation’ as both the mutations confer notable advantages to the virus.
The L452R mutation can escape some monoclonal antibodies, and could also potentially increase infectivity or the ability to infect a host. The E484Q mutation can also escape antibodies. Variants with either mutation are thus not effectively neutralised by plasma therapy.
A double mutation is a naturally occurring result of the virus constantly mutating — most variants end up carrying multiple mutations.
However, the novel variant is of concern as both notable mutations are immune evasive.
A total of 771 samples have tested positive for mutations or variants of concern, in over 10,000 samples as of this week. These included the UK variant, Brazil variant, the South African one, as well as the double mutation.
As many as 206 samples in Maharashtra have tested positive for the double mutant variant that carries both L452R and the E484Q mutations. It has also been found in sequences in Delhi and Nagpur, but a corresponding surge in the number of cases has not been visible in these areas, clarified authorities.
Pathology of new variant
It is as yet unclear how exactly the virus variant with the two mutations behaves when compared to other variants.
A mutation is when ribonucleic acid (RNA) changes occur in viruses as a result of constant multiplication induced errors, and this results in minor changes to the viral structure.
The virus is made up of RNA, and thus when it multiplies, it can pass errors on to the new RNA code. These causes changes in how genes are expressed and this results in mutations.
For example, in the E484Q mutation, the glutamic acid (E) is replaced by glutamine (Q) at the 484th position on the virus’s spike protein, the protein through which the virus enters the human cell. This mutation has been found in multiple other variants as well, including the UK and South African variants.
As the name suggests, a variant is genetically different from the original strain or type of virus, but not different enough to be categorised into a new strain all on its own. A variant is typically made up of one or more mutations.
The virus constantly mutates and, due to this, some mutations might prove to be advantageous to the virus by sheer accident, and these could persist.
Supposed advantages include increased infectivity or ability to infect a host, increased transmissibility or ability to spread between hosts, and immune evasion or the ability to hide from the body’s immune system.
While both mutations have been noted to have immune evasive properties, detected in multiple countries, and the L452R mutation has been associated with a rapid spread of cases, there hasn’t been enough sequencing in India to effectively establish this combination of mutation as the cause behind the latest and ongoing surge in cases.
(Edited by Debalina Dey)