What Do We Know About The Indian "Double Mutant" Of The Coronavirus?

A new variant of the coronavirus has emerged in India, while the health situation is alarming. What do we know about these mutations and their effects on the biology of the virus? Here are the first elements available.

Since March 2021, India has been drowned in an ever-increasing number of coronavirus cases. In recent days, the country has recorded more than 200,000 new daily contaminations, for a total of 15.6 million cases and 182,553 deaths at the last count. This unprecedented rebound in the epidemic coincides with the circulation of a new variant of the coronavirus. 

The new virus mutant belongs to the B.1.617 lineage; this Indian variant was first spotted on October 5, 2020, during the screening of a 31-year-old man in Maharashtra. 

What do we know about the mutations of this variant, its transmissibility and its lethality? For the moment, it has not been the subject of extensive scientific studies, but some of its characteristics are already known.

The Indian "Double Mutant"

Although identified last October, the Indian variant has only been actively circulating in the Indian population for a few weeks. On March 24, 2021, the Ministry of Health in India communicated on the emergence of an unknown variant responsible for 15-20% of samples sequenced by Insacog ( Indian SARS-CoV-2 Consortium on Genomics). 

What are the characteristic mutations of this variant? It was nicknamed the "double mutant" by the media because of two critical mutations in its S protein, already observed elsewhere. The first mutation concerns position 484 of the S protein, which is also present on the Brazilian and South African variants. For the latter two, it is a lysine that replaces glutamic acid (E484K). For the Indian variant, it is glutamine (E484Q).

As a reminder, the E484K mutation was associated with a better escape from the immune system. In other words, these variants are more resistant to neutralizing antibodies resulting from natural infection or vaccination. But, for the moment, there is nothing to formally certify that the E484Q mutation causes the same effect. 

The other primary S protein mutation is L452R, found in the California variant of the coronavirus. According to a pre-published study, this mutation increases the virus's transmissibility from 18 to 24% and has a significant impact on the neutralizing power of antibodies. No study on the lethality of the Indian variant has yet been carried out.

A Variant Already Out Of Indian Borders

This variant has been identified in a challenging health context. Still, no apparent link with the emergence of the Indian variant has been established for the moment, according to a document on the variants published by Public Health France on April 8, 2021. Relaxation in respect of sanitary measures is also a possible explanation.

At the end of March, Indians traditionally gather for the Holi festival. Although banned in several states, including New Delhi, celebrations bringing together many people, most often without a mask, still took place. India has decided to seal its capital, New Delhi, on Monday and for a minimum of one week.

Europe is not spared by the Indian variant, which has already crossed the globe. In the UK, 154 cases have been identified in the past four weeks. Germany, Belgium and Switzerland have also detected a few instances. The variant is not present in metropolitan France, but two cases have been confirmed in Guadeloupe.