Unique virus mutation in Bengal

NEWDELHI: After Kerala and Gujarat, West Bengal has sequenced the SARS-CoV-2 genome and identified one unique mutation in the S2 domain of the spike protein of the virus in all samples sequenced from the state when compared to those sequenced in the other two states and Wuhan in China. There is one more mutation in S1 domain of the spike protein, which is similar to what Gujarat has found.

S1 attaches the virus to the cell membrane by interacting with host receptor while S2 mediates fusion between the virus and cell membrane , according to Uniprot which provides resources on protein sequence.

But it is too early to say how these mutations will affect us, said independent experts. The paper, led by CSIR Institute of Chemical Biology, Kolkata, and the Academy

of Scientific and Innovative Research (AcSIR) in Ghaziabad, said that five sequences from Bengal have been deposited on the Global Initiative on Sharing All Influenza Data (GISAID) on April 27. Scientists compared the sequences from the state with other sequences reported in India and with isolates of Wuhan origin.

Authors explain in their paper which is yet to be peer reviewed published in Medrxiv, a pre-print server for health research, that when a virus tries to adapt to a new environment it would change its genetic makeup to utilise the host’s body in favour of its survival. Broad mutation profile of this protein from extensive genome sequencing from different geographical areas is key to designing effective vaccine.

While the sequences from Bengal do tell us they are different from those in Gujarat and Kerala, the knowledge is inadequate in understanding how that can impact virulence or disease.

“There appears to be a new mutation in West Bengal. Some mutations are important while some are not. It’s too premature to say anything,” said Dr Shobha Broor, former head of the AIIMS department of virology, who has read the study.

There can be better understanding only though large scale global sequencing studies but for now it doesn’t seem like SARSCoV-2 is mutating very rapidly. “The question is whether one vaccine will hit all viruses globally. There are umpteen examples in case of measles, polio, where one vaccine managed to hit all mutated viruses globally. The mutations in SARS-CoV-2 are unlikely to affect the critical part of the spike glycoprotein. As of now, one vaccine is expected to protect all,” said Dr T Jacob John, professor emeritus and former head of virology at Christian Medical College, Vellore.