Hyderabad: After Delta Plus or B.1.617.2.1 or AY.1 , which has already been listed as variant of concern (VOC), health experts now have called for a close monitoring of four emerging coronavirus variants: B.1.617.3, a sibling of the Delta variant (B.1.617.2); B.1.1.318, which has 14 mutations; and Lambda (C.37), which was designated as a variant under investigation on June 23; Kappa (B.1.617.1), another sibling of the Delta variant, that too needs to be closely monitored, though it has thus far been less infectious than Delta or Delta-plus.
While B.1.617.3 and B.1.1.318 are already present in India, Lambda is yet to make its way into the country though it is spreading fast across the world. Experts fear that opening of international air travel may bring a cocktail of new variants, including Lambda, into India. They also called for more genomic surveillance to identify and find solutions to emerging variants.
The double mutant B.1.617, first identified in Maharashtra, gave rise to three variants – B.1.617.1, B.1.617.2 and B.1.617.3. The WHO had named B.1.617.1 as Kappa and B.1.617.2 as Delta. It did not name the B.1.617.3 variant and it is now clubbed under the Kappa group. As on June 22, India has reported 148 genome sequences of B.1.617.3 from the total worldwide sequences of 161. As far as the Kappa variant is concerned, India has thus far reported 3,083 of the 4,217 sequences from around the world.
The variant B.1.1.318 contains the mutation E484K. According to GISAID data, India has reported two genome sequences of this emerging variant of 173 reported around the world.
According to Dr Vighnesh Naidu Y, consultant physician at Yashoda Hospitals in Hyderabad, viruses tend to mutate as they multiply, and mutations are tiny errors in the original genetic makeup of the organism. “As these mutate, they change the ability of the virus to infect in terms of faster rate of transmission, increased virulence and their ability to evade our immune response,” he told TOI.
The Public Health England (PHE) announced Lambda as a variant to be kept under watch as its presence was reported from several countries.
Senior geneticist Dr M Khaja said the PHE has noticed a combination of mutations in the Lambda variant. The GISAID data shows that 1,845 sequences of Lambda have been posted from across the world. None of them is from India. The PHE, in its June 25 report, warned that Lambda has the potential of increased transmissibility and possible increased resistance to neutralising antibodies. The effectiveness of existing vaccines needs to be tested against Lambda.
Dr Vighnesh told a leading media house that continued genome sequencing of emerging variants will help in understanding the kind of symptoms they might present, the severity of the disease or the rate at which they could spread. Such studies will also help experts understand if the mutations have no consequence to humans. “The more we test the better we understand the prevailing strains,” he added.