‘Double mutant’ variant: new Indian strain of Covid-19 could contain multiple mutations

The new India variant has been described as a “double mutant” strain, where two mutations have come together in the same virus.

Experts are anxious to test whether it is more infection, less affected by vaccines or causes more pronounced symptoms of Covid-19.

The “Indian strain” was detected by Indian genomic scientists analysing samples from the western state of Maharashtra. The strain found there contains two mutations.

E484Q – a mutation similar to E484K, first seen in the South African and Brazilian variants – and L452R, first identified in the so-called "California variant" from the US.

What is a double mutation?

Double mutations are not rare, with one expert telling the BBC it is now “extremely common” to see more than one mutation at once,” in new variants.

"Such [double] mutations confer immune escape and increased infectivity," the Indian health ministry said in a statement.

In the early days of the pandemic, most mutations only had one spike protein, that is, the protein that the virus uses to latch on to and enter human cells.

Now, estimates suggest there are over 40 found around the world with at least two spike proteins. The Indian variant – already described as a ‘double mutant’ is likely to have more, but this will need to be verified through testing.

The more spike proteins a virus has, the more likely it is to be able to evade antibodies, which in turn could make it more infectious.

Should we be worried?

New variants are perhaps the most obvious threat to lockdown easing roadmaps and plans, as new strains that could evade vaccines and cause more infections are likely to cause case numbers and hospitalisations to rise.

At this stage, there is no indication as to whether the Indian variant could do that, but testing and research is still yet to get fully underway.

The worst case scenario would see the emergence of a new strain of Covid-19 that is not just more infectious, but which causes more severe symptoms, and could even reinfect those who have already suffered with the virus.

If that were to happen, scientists say those reinfections would only be mild relative to the symptoms experienced in the first bout of the disease.

But if the virus could reinfect those who have already have it, the concept of herd immunity (the point at which a large enough section of a community becomes immune to a virus) starts to look very shaky indeed.

Again, there is no data to suggest this is the case at the moment, and more testing needs to be done.

Is the variant the reason for India’s woes?

India reported 47,262 cases and 275 deaths on Wednesday 24 March - the biggest daily rise the country has recorded in 2021.

Dr Rakesh Mishra, director of the Hyderabad-based Centre for Cellular and Molecular Biology (CCMB), told the BBC that the new variant had been picked up in around 20 per cent of the cases in Maharashtra, an area which has witnessed a dramatic rise in cases.

But Dr Mishra said it’s unlikely a newer variant is to blame for increasing numbers in India, as “80 per cent of the samples we have sequenced don't have this combination of mutants.

"This mutant has been linked to only 230 cases in Maharashtra of the several thousand samples sequenced," he said.

In fact, India is more worried about the UK’s exported “Kent variant”, which is now dominant in Britain and spreading across the world.

A total of 736 of the 10,787 samples sequenced in India have been found positive for this variant.

India is also experiencing delays with its vaccination programme, and has placed a temporary hold on all exports of the AstraZeneca vaccine due to domestic demand caused by rising cases within the country.

Officials have described the move as a “temporary squeeze” which is expected to affect supplies in the UK until the end of April, according to the BBC, with some 190 countries under the Covax scheme likely to be affected.