Dr. Mala Kaneria, Consultant, Department of Infectious Diseases, Jaslok Hospital, Mumbai, helps answer your questions.
How many variants of SARSCoV2 are there in India?
Viruses are known to mutate by nature and these mutations are important for their survival and spread. The original Wuhan strain of SARSCOV2 has mutated several times since its appearance.
Many variants have caught the attention of health authorities, such as Alpha, Beta, Gamma, Delta, Delta Plus, Lambda, Eta and Lota. B.11.318 and B.1.617.3 are some other variants.
What is the difference between the variants?
The Delta variant (B.1.617.2), which was first found in India, was a variant of interest (VoI) in April 2021 and subsequently became a variant of concern (VoC) in May 2021, when it led to the second deadly COVID-19 Wave, which devastated the country. Delta has emerged as a threat around the world, as the majority of current Covid-19 cases in the world are the Delta variant. The Delta variant is not only several times more transmissible and causes more severe symptoms, but it is also 8 times less effective against vaccines compared to the original strain of COVID-19. This mutant is now found in most countries and is responsible for the increase in cases in the UK and Israel.
The Delta Plus variant (AY.1), a derivative of the Delta wave, contains the K417N spike protein mutation, which was first seen in the Beta variant (South Africa). This is a worrying variant (VoC), as the vaccines were not found to be very effective against the related Beta strain.
The Kappa variant (B.1.617.1), also related to the Delta variant, has two mutations (L452R and E484Q), of which L452R is an escape mutation that provides immune protection to the virus. Two cases of Kappa have recently been reported in Uttar Pradesh.
Lambda, the seventh VoI, which contains the L452Q and F490S mutations, originated in Peru, the country with the highest mortality. Both Kappa and Lambda are currently labeled Variants of Interest (VoI) by the WHO.
Which is more lethal or dangerous?
Delta is the deadliest, as it was responsible for the large number of cases and an increase in deaths during the second wave in India. Delta Plus, being a derivative of Delta, also has attributes of higher transmissibility, the ability to bind more strongly to receptors on lung cells, and the potential to evade an antibody response, although there is no concrete data on lethality. However, some scientists believe that K417N can actually weaken the Delta Plus strain and may not be as lethal as the Delta strain. Not much is known about the lethality of Kappa and Lambda, which is currently not found in India.
Why is Delta Plus called ad VoC while Lambda is called VoI?
If a variant is found to be more transmissible, more resistant to antibodies, or to cause more serious disease, it is called a VOC. Delta and possibly Delta Plus have exhibited these traits and are therefore called VoC. However, so far there are no cases of Lambda in India and its lethality is unknown, so it is only a VoI at present.
Are these new variants resistant to vaccines?
Existing vaccines work against the original Delta variant, but are less effective in those who do not develop a robust immune response. The Delta Plus variant due to its K417N escape mutation, can dodge vaccines and antibodies better than Delta. However, the major vaccines are believed to offer protection against serious illness and hospitalization against most strains.
What vaccines are most effective?
The AstraZeneca and n Pfizer vaccines remain highly effective against the Delta and Kappa variants. There is no evidence of widespread release to suggest that the current generation of vaccines will provide protection against the B.1.617 lineage. However, the level of neutralizing antibodies in the blood can be lowered, which can lead to some breakthrough infections. Recent data shows that a third booster dose of Pfizer would be more effective against the Delta strain, as the antibodies against this variant decrease more rapidly.