Covid double mutant at least twice as infectious as earlier variants, say Indian scientists

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Express News Service

NEW DELHI: Early indications from an analysis of the growth of the B.1.617 variant of the Covid-19 virus has shown it to be at least twice as infectious as the UK variant and thrice as infectious as the variant behind last year’s Covid-19 wave.

The findings follow the admission by the government recently that this lineage of the virus may be behind the rapid Covid-19 surge in several states in India. 

Scientists involved in the whole genome sequencing as part of the Centre’s Covid-19 genomic surveillance exercise told The New Indian Express that this conclusion is based on the growth of this mutant, as compared to others, in districts where B.1.617 has been identified along with other variants in samples collected from infected individuals.

“We have been examining this data carefully and the way this lineage of virus, also called the double mutant, is growing as compared to others is remarkable,” said a senior scientist involved in the INSACOG project, a consortium of several institutions under the National Centre for Disease Control that carry out an extensive genomic surveillance. “For the public, what needs to be communicated very clearly is that there is a greater need to double mask and maintain social distancing as this virus is highly infectious.” 

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Their analysis, he said, has confirmed that B.1.617 lineage of SARS CoV-2, which was declared a variant of concern in the UK on Friday, is 50-70% more infectious as compared to the B.117 lineage or the UK variant.

On Monday, in a briefing by the Union health ministry, NCDC director Sujeet Kumar Singh, while declaring the B.1.617 as a variant of concern for the first time, said that it may be driving the Covid-19 surge in India.

As per the figures shared by him, samples collected from at least 18 states, which have undergone genomic surveillance, have shown the presence of this variant with a large number of samples from Delhi, Andhra Pradesh and Telangana apart from Maharashtra where the variant was first detected.    

This variant with — E484Q and L452R together — had been first identified in February and its spread has been growing ever since, overtaking several other variants. In other countries, it has been established that while E484Q can escape antibody neutralisation, L452R is known to increase transmissibility.

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Singh, in the briefing, however, insisted that an exercise was still underway to establish the correlation between the lineage’s rise and its clinical and epidemiological significance.

He did not respond to a query by The New Indian Express on the status of this exercise but another scientist associated with the INSACOG too said that a preliminary analysis of how B.1.617 and B.1.117 are behaving in locations where they co-exist and how their proportions are changing week after week has been completed.

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The scientists used data from Maharashtra, Bengaluru, West Bengal Bengal, Kerala and the UK and at all these places, they were able to obtain week-by-week sequencing data. 

In Kerala, B.1.617 has gone from 0% to 7% in two months while in the UK too, this lineage has changed from 0% to 6% over the 8 weeks.

“If both were equally infectious, they should also change at the same rate but that is not the case — the rate of growth of the double mutant virus is over twice that of the UK variant but we will have a clearer picture in a week’s time,” he said.

A study carried out by ICMR scientists, including its chief Balram Bhargava, meanwhile has also found that B.1.617 lineage caused more severe disease in hamsters and raised the chances of hypoxia, but virologist Shahid Jameel, chief advisor to INSACOG, when approached for his opinion said that he was cautious but not yet “concerned”.

“While hamsters are a good model to study transmission, I am not sure if they accurately predict disease severity in humans,” he said.



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