Bhubaneswar: Are sub-lineages of the SARS-CoV-2 Delta variant — AY 12 and AY 4 — responsible for a significant rise in breakthrough cases in Odisha?
A senior scientist at one of the labs associated with the Indian SARS-CoV-2 Genomics Consortium (INSACOG) told a national daily that these two sub-lineages of Delta have been found in around 90 per cent of the current samples.
The AY.4 and AY.12 sub-lineages have been detected in 650 of 468 and 382 samples sequenced in July and August respectively. These were mostly drawn from Bhubaneswar, Khurda, Cuttack, Puri, Balasore, Kendrapada, Jagatsinghpur, Bhadrak and Ganjam, a TNIE report said.
Several cases classified as Delta in July are now being reclassified as AY.4 and AY.12 and this is possibly behind the recent surge in new cases among the vaccinated people in the state. Most of the AY.4 sub-lineage has been detected among those who have got the single shot.
Notably, AY.12 had been driving fresh cases in Israel, where around 60 per cent of the population have been fully vaccinated.
The INSACOG said the functional impact of the changes between Delta and AY.12 is not known but the two appear to be very similar at a molecular level. “Delta variant is the major VOC 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,” the INSACOG said in its recent bulletin.
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, it said.
Besides Odisha, the sub-lineages have reportedly been found in Karnataka, Telangana, Maharashtra, Mizoram, Assam and Bihar.
The scientist, however, claimed that the vaccines continue to protect a person and it is very rare for someone vaccinated to experience severe illness or die.