The health ministry on Wednesday said a "double mutant" variant of coronavirus has been detected in over 10,000 samples analysed across 10 national labs. Apart from the 'double mutant variant', three major variants, also known as 'variants of concern' or VoCs, that have spread across the UK, South Africa and Brazil, have also been detected in the samples analysed in India.
Though the Centre says VOCs and the "new double mutant variant" have been found in India, they have not been detected in numbers sufficient to either establish or explain the recent surge of Covid-19 cases, especially in five states of India.
But what is a "double mutant" variant?
According to experts, viruses keep on changing their structure, also known as a mutation, in small ways as they spread from one human to another. While most of such mutations are harmless and fail to alter the virus behaviour, some of them can trigger changes in spike protein.
Viruses like coronavirus latch on to spike protein to enter the human body. Experts say a "double mutant" is more infectious, which not only spreads faster and causes severe disease but also leaves vaccine shots ineffective.
Covid-19 vaccines that have been approved across the world so far have properties that create "neutralising antibodies" in our body, which blocks the virus from entering the body. But these VoCs and "double mutants" can escape these antibodies.
The centre has said a total of 771 variants of concerns (VOCs) have been detected in a total of 10,787 positive samples shared by 18 states/UTs. The analysis of samples from Maharashtra has revealed that compared to December 2020, there has been an increase in the fraction of samples with the E484Q and L452R mutations.
"Such mutations confer immune escape and increased infectivity," the ministry said. These mutations have been found in about 15-20% of samples and do not match any previously catalogued VOCs, it added.
The experts say a virus variant is declared 'VoC' only after many mutations so that it begins to operate differently. While E484Q mutation is believed to be seen in South Africa and Brazil, L452R is believed to be similar to the one detected in the US, also known as the "California variant".
As per scientists, such mutations are not rare and keep on happening as the virus spread from places to places. However, they warn that mutations can make the virus stronger and capable of evading neutralising antibodies.
In some cases, the mutated virus can even infect those who have already recovered from coronavirus, though the number may not be high. The more it evades antibodies, the more it penetrates the herd immunity, thereby increasing the infection rate.
Similarly, the government has also found the N440K variant, also associated with immune escape, in 123 samples from 11 districts. This variant was earlier found in 33 percent of samples from Andhra Pradesh, and 53 of 104 samples from Telangana. Also, it has been reported from 16 other countries including the UK, Denmark, Singapore, Japan and Australia. Experts say though the "double mutations" found in India may not be as harmful as other variants, more data will be needed to assess its actual impact.