As cases spread in India, the sub-lineage of B.1.617, B.1.617.2, is beginning to eclipse other variants including the Kent variant, B.1.1.7 that originated in the UK. Kerala, Andhra Pradesh, Telangana and Karnataka has seen cases of B.1.617.2 spread wide. Uttar Pradesh, Delhi, Gujarat, Maharashtra, Puducherry and Bihar have also shown more cases of the new sub-lineage, B.1.617.2.
A genome sequencing expert in Hyderabad said that out of 100 samples, around 25-30 samples are of the B.1.617.2 variant. Dr Vinod Scaria, Scientist at CSIR-Institute of Genomics and Integrative Biology (IGIB) told India Today, "B.1.617.2 is the predominant lineage in the recent months. At least in Kerala from the recent analysis done, B.1.617.2 is the predominant sub-lineage in many districts in Kerala. In fact, the present wave during April and May months seems to be because of this variant."
Experts have said that the variant is 40-50 per cent more transmissible than the original parent variant of B.1.1.7.
The B.1.617.2 variant has been found in 48 countries. UK Prime Minister said he was 'anxious' about the variant, while experts recommended against lifting restrictions in Britain stating that B.1.617.2 is likely to become the dominant strain in the country.
As of May 7, India sequenced 1,124 samples of this variant with a cumulative prevalence of 15 per cent. As of May 16, the UK showed the highest sequences detected at 4,314 cases but the cumulative prevalence rate was lesser than in India, at 6 per cent. The US sequenced 821 cases with a cumulative prevalence of 0.5 per cent. Cumulative prevalence is the ratio of the sequences containing B.1.617.2 to all other sequences collected since identification of B.1.617.2 in that location.
Addressing fears that B.1.617.2 evades the vaccine effect, experts said that it is not complete evasion but lower protection if large populations have received only first dose. Two doses of AstraZeneca vaccine are 60 per cent effective against symptomatic disease from the B.1.617.2 variant compared to 66 per cent effectiveness against the B.1.1.7 variant.
"Only 1.1 per cent of B.1.617.2 cases required hospitalisation, compared to 1.5 per cent of B.1.1.7. Non-variant cases were also 1.1 per cent. This shows that the clinical picture of B.1.617.2 is perhaps no more severe than the old virus. Soon the older virus will be overtaken by the newer variant, which is natural," said Dr Rajeev Jayadevan, scientific advisor and former president IMA, Kochi, Kerala to the news site.
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