‘Double mutant’ coronavirus variant emerges in India and California 

The number of concerning SARS-CoV-2 variants continues to increase. One notable example is a variant known as a ‘double mutant’ that arose in India. The variant has two mutations that could make the virus more virulent and resistant to antibodies, according to a preprint on bioRxiv.

Researchers at the Stanford Clinical Virology Lab recently confirmed the presence of the variant in California.

There is circumstantial evidence in India that the variant is more infectious because it is responsible for 20% of cases in the Indian state of Maharashtra, where cases have ballooned by more than 50% in the past week.

There is also a theoretical basis for the increase in infectivity from the variant. A single mutation with the receptor-binding domain portion of the coronavirus spike protein can significantly reduce viral neutralization.

The L452R and E484Q mutations in the double mutant could reduce antibody neutralization, but that assumption has not been confirmed in official studies.

A “double mutation in key areas of the virus’s spike protein may increase these risks [of being more infectious] and allow the virus to escape the immune system,” George Institute for Global Health virologist Shahid Jameel told BBC.

Researchers first found a COVID-19 variant with the L452R mutation in minks in Denmark. Scientists later found it in humans in California.

A preprint study found that two viral lineages with the mutation (B.1.427 and B.1.429) were between 18.6 and 24% more transmissible than the earlier SARS-CoV-2 strain.

The E484Q mutation found in the ‘double mutant’ strain is similar to the E484K mutation, which has been nicknamed “eek.” The E484K mutation is found in both South Africa (501Y.V2) and Brazil (P.1) variants.