Hyderabad: Geneticists from Hyderabad-based Centre for Cellular and Molecular Biology (CCMB) have completed analysis of more than 2,000 SARS-CoV-2 genomes from India available in the public domain, which has the potential to throw light on why Covid-19 infectivity in the country was on the higher side.
In June, the CCMB team revealed the presence of a distinct virus population among Indians, which was named the clade I/A3i. At that time, 41 per cent of all Indian SARS-CoV-2 genomes belonged to this clade, which according to current analysis, had dropped to 18 percent.
The findings of the study, which is a collaboration between CCMB and CSIR-Institute of Integrative Biology, was published in the journal Open Forum Infectious Diseases of the Oxford University Press.
The findings made it clear that no clade at present has been conclusively shown to be associated with a more severe form of Covid-19, or an increased risk of death.
“We expected A3i clade to slowly disappear with time, and other clades without this variation to prevail and this is what we see now”, said Dr Divya Tej Sowpati, Scientist at CCMB, who is leading this study, said.
The decrease in the proportion of A3i clade is accompanied by an increase of the A2a clade, which is shown to be associated with an increased infectivity. At present 70 per cent of all Indians as well as global SARS-CoV-2 genomes fall into this clade.
“As expected for a strain which is more infectious, A2a clade quickly became the dominant clade in India just like everywhere else. There is no evidence to state that this mutation is clinically a more difficult one. The similarity in viral genome globally should be considered a positive news, because a vaccine or a drug targeting this mutation will work with the same effectiveness all over the world,” said Dr Rakesh K Mishra, Director, CCMB and a co-author of the study.