BHUBANESWAR: Even as no new variant of SARS-CoV2 has been detected in the State after the Delta Plus (AY.1) mutant in April, two new sub-lineages of Delta (B.1.617.2) could be driving fresh Covid cases in Bhubaneswar, claimed to be the first fully vaccinated city in the country. The State Capital has been recording on an average of 250 cases for around two months now and around 80 per cent (pc) of them are fully vaccinated or inoculated with a single dose.
Sources said Delta variant’s new sub-lineages, AY.4 and AY.12, now the main variants of concern (VOC) in the country, are responsible for significant rise in breakthrough infections in the State, especially the Capital city. Of the 468 and 382 samples sequenced in the State in July and August respectively, the AY.4 and AY.12 sub-lineages have been detected in 650 samples, which were mostly drawn from Bhubaneswar, Khurda, Cuttack and coastal districts of Puri, Balasore, Kendrapara, Jagatsinghpur, Bhadrak and Ganjam.
According to the statistics provided by the Indian SARS-CoV-2 Genomics Consortium (INSACOG), a total 4,215 samples have been sequenced in the State since January and Delta variant was detected in 2,466 samples. A senior scientist at one of the labs associated with INSACOG said although the Delta variant was found in most of the samples collected for sequencing after April, in current samples in Odisha, the two sub-lineages of Delta are predominant with around 90 pc of the samples.
“The AY series are included in Delta, which is possibly behind the recent surge in new cases among the vaccinated people. Though the functional impact of the changes between Delta, AY.4 and AY.12 is yet to be ascertained and the clinical correlation has not been done, those appear to be very similar at molecular level. The sub-lineages have also been found in Karnataka, Telangana, Maharashtra, Mizoram, Assam and Bihar,” said the scientist.
After the detection of the new sub-lineages, several cases classified as Delta in July are now being reclassified as AY.4 and AY.12. The AY.4 is a major evolutionary branch of Delta though it presently has no other known clinical significance. The AY.12 was first classified in Israel and led the surge in new cases. The INSACOG scientists, however, claimed that the vaccines continue to protect against severe disease and remain a cornerstone of public health strategy.
Most of the AY.4 sub-lineage has been detected among the single dose vaccinated. Meanwhile, the labs conducting genome sequencing on Thursday moved the Union Health Ministry to obtain ethical permission for sequencing of samples of children.
4,215 samples sequenced in the State since January
Delta variant detected in 2,466 samples
Several cases classified as Delta in July now being reclassified as AY.4 and AY.12
Sub-lineages have been found in Karnataka, Telangana, Maharashtra, Mizoram, Assam and Bihar