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Indian SARS-CoV-2 variant B.1.617.2: Part 3

By Rohan Bandi, Dental Tribune South Asia
May 21, 2021

This is a series of updates by Dr. Rohan Bandi (MDS) Prosthodontist, Mumbai on the emerging lines of evidence on B.1.617.2, the Indian variant of SARS-CoV-2. Part 3 of the series describes the current status of B.1.617 and the impact of its mutations on the vaccines .

Significance of B.1.617:

In West Bengal, India's Eastern state, with recently conducted elections, the Bengal genome seems to be dominated by the B. 1. 617 lineage.

Prominent US disease modeler Chris Murray from the University of Washington said the sheer magnitude of infections in India in a short period suggests an "escape variant" may be overpowering any prior immunity from natural infections in those populations.

"That makes it most likely that it's B.1.617," he said. But Murray cautioned that gene sequencing data on the coronavirus in India is sparse and that the UK and South African variants are also driving many cases.

Carlo Federico Perno, Head of Microbiology and Immunology Diagnostics at Rome's Bambino Gesù Hospital, said the Indian variant couldn't alone be the reason for India's sudden and massive surge, pointing instead to large social gatherings.

How dangerous is the Indian variant (B. 1. 617 lineage)?

It is hard to tell, but with substantial official daily deaths recorded apart from an even more significant number of unrecorded deaths across India, there is a chance that it could be more lethal than its precursors. Scientists and researchers are also working to confirm whether or not the variants are more dangerous than others in circulation, for example, by spreading more quickly, causing more severe disease, or evading immunity built up from previous infection or vaccination.

The two key mutations in the Indian variant could be enabling it to spread rapidly. L452R could be helping the virus evade some antibodies from vaccination, while E484Q, with its similarities to the E484K mutation (also seen in the South African variant), could be making the Indian variant at least partially resistant to vaccines.

Even with all these mutations, the Indian variants are highly improbable to render vaccines completely ineffective because of the broad immune defenses induced by the vaccines.

There are some early results – yet to be peer-reviewed – from the laboratory of Prof Ravi Gupta at the University of Cambridge. They suggest that each of the two mutations - L452R and E484Q - reduce the neutralizing ability of antibodies generated by one dose of the Pfizer vaccine. Although each mutation can lower the neutralizing ability by four-fold to six-fold compared to its pre-existing form of the virus, it does not seem to have an additive effect. In other words, the drop in neutralizing ability does not get amplified even when the mutations appear together.

By contrast, the E484K mutation seen in certain other variants, such as that first detected in South Africa, has been linked to a tenfold reduction. Gupta further said that his team's data suggested all three variants first detected in India might be more transmissible than the original SARS-CoV-2 strain. The greater transmissibility could be due to a mutation called P681R – similar to the one seen in the Kent variant – and which experiments suggested might help the virus enter the cells. [7]

Indigenously-developed Bharat Biotech's Covid-19 vaccine Covaxin neutralizes multiple variants of SARS-CoV-2. Covaxin effectively neutralizes the double mutant strain as well, the Indian Council of Medical Research (ICMR) said in a tweet.

References

  1. https://genomeconnect.blogspot.com/2021/04/ever-evolving-invader-emergence-of-sars.html?m=1&s=08
  2. https://www.theguardian.com/world/2021/may/06/new-concerns-indian-covid-variant-clusters-found-across-england-ongoing-risk-high
  3. https://www.timesofisrael.com/children-from-5-schools-among-israels-41-cases-of-indian-covid-strain/
  4. https://theprint.in/science/double-mutant-triple-mutant-bengal-lineage-covid-variants-driving-india-surge-decoded/643766/
  5. https://theprint.in/health/b-1-117-to-b-1-618-india-has-many-covid-variants-causing-infections-here-are-the-dominant-ones/644693/
  6. https://www.reuters.com/business/healthcare-pharmaceuticals/what-we-know-about-indian-variant-coronavirus-sweeps-south-asia-2021-04-30/
  7. https://www.theguardian.com/world/2021/may/04/no-surge-testing-for-india-variants-despite-hancock-pledge
  8. https://timesofindia.indiatimes.com/india/covid-as-drive-slows-gap-between-jabs-and-vaccine-seekers-grows/articleshow/82510216.cms

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