NEW DELHI: A new sublineage AY.12, of the delta variant of SARS-CoV -2, that was recently classified in Israel is now being seen in many states in the country. Many cases earlier recorded as having been caused by the Delta variant are now being reclassified as AY.12 infections, the latest report of the genomic surveillance consortium says.
The weekly bulletin by the Indian SARS-CoV-2 Genomics Consortium (INSACOG) said that the AY.12 sublineage is responsible for a surge in breakthrough infections in Israel but the functional impact of the changes between Delta and AY.12 is not known yet, though the two appear to be very similar at a molecular level.
Since the definition of AY.12 is inconsistent, it will take some time for final numbers to emerge, the consortium said.
"In summary, Delta variant is the major variant of concern in India at this time. AY.12, a reassigned sub-lineage of Delta is being seen in many states, but the numbers need closer examination," it said.
Globally, the report says that Delta continues to expand around the world with Israel seeing new cases rising to near previous highs despite about 60 per cent of the population being fully vaccinated.
"AY.12 is the dominant lineage in Israel as per outbreak info and is one of the reclassified Delta sub-lineages. It is not currently known whether AY.4-AY.12 are clinically different from Delta. AY.12 has lost some of the mutations seen in Delta parent lineage, including G142D in spike protein. No new mutations of concern are noted in the spike protein (S). However, its rapid growth in Israel means that it should be examined further," it added.
Of the 31,124 samples sequenced by the INSACOG, 21,192 turned out to be of carriers of the Delta virus.
The Delta variant is currently driving the pandemic across several countries with China and Korea seeing new highs. It was responsible for a surge in cases during the second wave in India in April-May this year.