HYDERABAD: Health experts have called for a strong surveillance on at least four emerging variants of Covid-19 apart from the Delta plus (B.1.617.2.1 or AY.1), which has already been designated as a variant of concern (VOC).
The emerging novel coronavirus variants that should be watched out for are 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, 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.
However, it is spreading fast around the world and 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 variant B.1.617.3, a sibling of the Delta variant, needs to be watched out.
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 Kappa group.
As of June 22, India has reported 148 genome sequences of B.1.617.3 from total worldwide sequences of 161.
As far as the Kappa variant is concerned, India has thus far reported 3,083 of 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, Yashoda Hospitals, 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 calling for scaling up genome sequencing of the virus and its emerging strains.
The Public Health England (PHE) announced Lambda as a variant to be kept under watch as it was reported from several countries.
Currently, no cases of Lambda have been detected in India, and increased genome sequencing may lead to its finding in the country.
Warning that resumption of international air traffic may bring new variants like Lambda, 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 potential of increased transmissibility and possible increased resistance to neutralising antibodies.
Lambda has mutations in the spike protein including notable mutations like G75V, T76I, L452Q, F490S, D614G and T859N.
The effectiveness of existing vaccines need to be tested against Lambda.
Dr Vighnesh told TOI that continued genome sequencing of emerging variants will help in understanding the kind of symptoms they might present, the rapid spread or severity of the disease.
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 and can put in place mechanisms to check the spread and strategies as to how to manage the sick,” he added.