DNA Explainer: What are the types of COVID-19 variants found in India?

The second surge of COVID-19 cases in India has swamped hospitals much faster than the first because mutations in the virus mean each patient is infecting many more people than before, epidemiologists and doctors say.

India, the world's hardest-hit country after the United States, has reported about 950 cases of people contracting the variants first detected in the United Kingdom, South Africa and Brazil.

Doctors at New Delhi's All India Institute of Medical Sciences have found that one patient is now infecting up to nine in 10 contacts, compared with up to four last year.

Among all the mutant Covid-19 variants in India, the double mutated virus, B.1.617, is becoming the most prevalent, according to genome sequencing data submitted by Indian scientists to a global database.

Types of COVID variants found in India

The variants that have been identified are informally associated with the name of the country where they were first discovered. They are referred to as the "UK" (B.1.1.7), the "South Africa" (B.1.351) and the "Brazil" (P1) variants, with the terms in brackets being their formal names.

India is grappling with the UK variant, South Africa variant, Brazil variant and the double-mutant, which combines mutations from two separate virus variants, found in samples from Maharashtra, Delhi and Punjab.

The double-mutant, classified as B.1.617 lineage, was found in 15-20 percent samples in Maharashtra. The B.1.617 variant contains mutations from two separate virus variants -- E484Q and L452R.

Some variants are specific to regions of India, including one called B.1.36, found to be present in a good fraction of cases tested in Bengaluru. The UK variant currently dominates new cases in Punjab.

As on April 15, out of 13,614 Whole Genome Sequencing (WGS) samples processed in labs, 1,189 samples have tested positive for variants of concern for SARS COV-2 in India.

This includes 1,109 samples with the UK variants, 79 samples with South African variant and 1 sample with the Brazil variant.

Recently, health experts said that the double mutant variant may be less dangerous than expected as the most vulnerable patients are having only mild illnesses.

The experts emphasised that as per the current evidence, new variants are observed from few states. But, details about its epidemiology are yet to be known.