New Delhi: A new sublineage of the SARS-CoV-2 Delta variant known as AY.12 has been detected in a number of states in India, and is most likely the cause of the latest surge of Covid cases in Israel.
According to the weekly bulletin by the Indian SARS-CoV-2 Genomics Consortium (INSACOG), the Delta variant continues to infect people around the world with Israel seeing new cases rising to near previous highs despite about 60 per cent of the population being fully vaccinated.
INSACOG is a multi-laboratory, pan-India network to monitor genomic variations in the SARS-CoV-2 by sequencing samples circulating in India.
In its statement, INSACOG said that many cases in India, which were earlier classified as Delta, are now reclassified as AY.12.
“However, since the AY.12 definition is inconsistent, final numbers will take some time,” the statement said.
Previously, INSACOG had described this new sublineage of Delta as AY.4. However, after a revaluation of the mutations that define this variant, it has been reclassified as AY.12.
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The difference between AY.12 and Delta
According to INSACOG, it is not known yet whether AY.12 is clinically different from Delta or B.1.617.2.
However, AY.12 has lost some of the mutations seen in Delta lineage, such as G142D in spike protein. No new mutations of concern are noted in the spike protein of this variant. However, its rapid growth in Israel means that it should be examined further.
AY.12 is, at present, the most dominant strain in Israel — 51 per cent of samples studied have shown the prevalence of this variant.
Based on the number of sequences that have so far been uploaded on the GISAID by Indian research groups, the prevalence of this variant over the last week has increased to over 20 per cent.
Outbreak.org which tracks new variants and their prevalence based on data uploaded in GISAID estimates that since the beginning of the pandemic, 1,504 samples of AY.12 have been uploaded from India — which is 4 per cent of the total variant samples.
The first sample of AY.12 in India dates back to 7 September 2020.
INSACOG has so far sequenced 67,699 samples of the virus from India, of which 50,869 have been analysed in detail. An additional 11,016 sequences of samples have been shared by state governments — taking the total number of samples sequenced so far to 78,865.
In contrast, more than 3.2 crore people have been infected in India so far which means just about 0.002 of samples in India have been sequenced.
(Edited by Paramita Ghosh)
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