As WHO warns that B1617, the Covid virus variant first detected in India, could be more contagious than most, a look at some SARS-CoV-2 variants of concern in the world today.

The double mutant B.1.617 variant of SARS-CoV2 is further mutating and one of its sub-lineages, the B.1.617.2, reported in India, is more infectious than its parent and fast increasing its footprint, according to Rakesh Mishra, former Director of the Centre for Cellular and Molecular Biology.

He also said there is nothing called the “Singapore variant”, a term that has led to a war of words between the Centre and the AAP government after Singapore objected to Chief Minister Arvind Kejriwal's tweet that a 'new' coronavirus strain in the city-state is very dangerous for children.

Singapore's health ministry on Tuesday night said the strain that is prevalent in many of the COVID-19 cases in recent weeks is the B.1.617.2 variant, which was first detected in India.

Amid criticism over Kejriwal's Singapore COVID-19 variant remark, Delhi Health Minister Satyendar Jain on Wednesday claimed there was a 'different strain' of coronavirus spreading in that country.

However, Mishra said B.1.617.2 has already been reported in India and is in the majority of the new cases in Karnataka and Andhra Pradesh.

COVID-19 Vaccine

Frequently Asked Questions

How does a vaccine work?

A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.

How many types of vaccines are there?

There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.

What does it take to develop a vaccine of this kind?

Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.

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“Among these three, B.1.617.2 is more infectious than B.1.617. That does not indicate a greater worry except the numbers are more and symptomatically. Otherwise, we have not seen any other difference. So this is now replacing others,” He said the same thing is being observed in the UK where B.1.617 was found and the sub-lineage has started to take over.

This is the same thing we are seeing in Singapore. Most of the cases in Singapore are B.1.617 and a majority is B.1.617.2 “B.1.617.2 sub-lineage is majority in the new cases in Karnataka and Andhra Pradesh,” Mishra said.

“Gradually it is increasing its footprint and it will be a major one replacing other variants,” he added. Another virologist, who did not want to be quoted, said the sub-lineage was first detected in India in December. Sujeet Singh, the Director of the National Centre for Disease Control, said in a webinar in April that in Maharashtra, the B.1.617 variant was found in over 50 per cent of samples in many cities while the UK variant was found in 28 per cent of samples in the second week of March.

B.1.617, termed as a double mutant, has three new spike protein mutations.

Two mutations E484Q and L452R are in the area important for antibody-based neutralisation. The third mutation P681R in B.1.617 along with the reversion of E484Q allows its sub-lineage to be more infectious. The World Health Organisation (WHO) has termed it as 'Variant of Concern'. According to the Centre for Disease Control and Prevention of the US, B.1.617.1 and B.1.617.3 sub-lineages have two receptor binding domain mutations --- L452R and E484Q. The former has seven spike mutation while the latter has 7-8. In case of B.1.617.3, it has 9-10 spike mutations and two receptor binding domain mutations --- L452R and T478K. In case of all the three sub-lineage, it has the potential to reduced antibody efficacy and potentially reduced neutralisation by vaccine sera, which, however, remains to be established.

On Tuesday, Kejriwal had tweeted, 'The new form of coronavirus in Singapore is said to be very dangerous for children. It could reach Delhi in the form of a third wave. My appeal to the Central government: 1. Cancel all air services with Singapore with immediate effect 2. Work on vaccine alternatives for children on a priority basis.' Responding to Kejriwal's tweet, Singapore's health ministry on Tuesday night said: “There is no Singapore variant. The strain that is prevalent in many of the COVID-19 cases in recent weeks is the B.1.617.2 variant, which originated in India. Phylogenetic testing has shown this B.1.617.2 variant to be associated with several clusters in Singapore,” it said in a statement.

B.1.617 variant of SARS-CoV2 has sub-lineages; nothing called Singapore variant: Expert

He also said there is nothing called the “Singapore variant”, a term that has led to a war of words between the Centre and the AAP government after Singapore objected to Chief Minister Arvind Kejriwal's tweet that a 'new' coronavirus strain in the city-state is very dangerous for children.

As WHO warns that B1617, the Covid virus variant first detected in India, could be more contagious than most, a look at some SARS-CoV-2 variants of concern in the world today.

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