COVID-19 India: The mutant strains we must know about

A combination of new strains, vaccine hesitancy and Covid-denial among people at large has led to a potent second surge of cases in India. We must do more than step up the vigil and ramp up the ongoing vaccination drive. Part of the reason why viruses are hard to control is their ability to mutate and change their forms. Coronavirus is no different. Here are the details about the mutant strains of the virus that are wreaking havoc around the world.

Sonali Acharjee

India 'Double mutant variant'

First found in the country in Dec. 2020, it has since become more prevalent. Twenty per cent of the samples (or 230 cases) from Maharashtra were found to have this mutation.

Is the double mutation a concern?

GISAID, an open sharing database, lists 43 viruses that have both the E484Q and L452R mutations in India. No increase in mortality has been linked to it.

What does the mutation do?

The E484Q mutation in the strain is similar to the one in the South African and Brazilian strains. Also known as the 'escape mutation', it helps the virus slip past antibodies previously created. The L452R has been found in the Californian variant and helps increase virus infectivity. This mutation has been dominant and increased significantly in the virus since Nov. 2020, indicating it might be favouring the evolution of Covid-19 by allowing it to enter human cells more easily.

Early China variant (D614G)

Emerging from Wuhan, it replaced the first virus identified in Jan. 2020, and became the dominant global strain by June

What does the mutation do?

Helps the virus attach more efficiently to the ACE2 receptor in the human host

How infectious is it?

Was found in 10 per cent of 997 global genome sequences before Mar. 1, 67 per cent seq uences from Mar. 1-Mar. 31 and 78 per cent sequences from Apr. 1-May 18, in a June 2020 study in the journal Cell

Prevalence in India: Was seen in 78 per cent of all samples between Apr. 1 and May 18, 2020.

South African variant (501Y.V2)

Fifty per cent more infectious in South Africa, it became the dominant strain in the country and has now spread to around 40 countries

What does the mutation do?

Like the UK variant, is more infectious. Another change, E484K, helps the virus dodge antibodies from previous infections and some vaccines

Potential for reinfection:

Unlike the UK variant, the South African strain infects those who have already had Covid

Prevalence in India 34 cases

Brazilian variant (P.1)

Associated with the surge of cases in Manaus, Brazil. It has since spread to 21 other countries.

What does the mutation do?

Some mutations not only make the variant infect faster but, like the South African variant, also help it escape antibodies generated through a previous natural infection or through vaccination

Potential for reinfection:

Research by the Brazil-UK Cadde project found that Manaus had 76 per cent of its population infected by the virus by October 2020. And yet, the new variant led to a lethal second wave

Prevalence in India: Only 1 case reported so far

UK Variant (B.1.1.7)

Found in the country in September, it is said to be behind the UK's deadly second wave. It has been termed a 'variant of concern' by the WHO.

What does the mutation do?

There were roughly 17 changes to the virus. One mutation, called N501Y, alters the "receptor-binding domain" of the spike. Another mutation, a H69/ V70 deletion, in which a small part of the spike is removed, helps the virus evade antibodies, according to a research by Cambridge University

Is it more infectious?

While an Imperial College study found it to be 70 per cent more infectious than the previous variants, an NIV, Pune study on hamsters found it to be as contagious as the early China variant. What is clear is that the strain has spread to 50 countries. In March 2021, the CDC predicted it will become the dominant strain in the US as it was doubling in prevalence every nine days. It was found to be 35-40 per cent more contagious than all other strains

Prevalence in India: 737 samples have tested for this variant, the maximum in Punjab

Mortality risk

A University of Bristol study has said the strain is associated with 64 per cent more mortality in the UK. In India, Punjab has the highest load of the strain and the highest mortality rate (3 per cent), nearly double the national figure.