Delta Variant Sub-Lineage A.Y.12 Now Fast Spreading In India Could Be More Transmissible While Study Shows That A.Y.3 Is Able To Infect The Vaccinated!
INSACOG or the India SARS-CoV-2 Genome consortium reports prevalence of the Delta variant sub-lineage A.Y.12 in India that has been linked to a COVID-19 surge in Israel.
Interestingly the Delta variant (B.1.617.2) has ‘birthed’ several sub-lineages or second generation variants or sub-species that bear most of its characteristic mutations but are different in other ways. To date, a total of 27 such second generation Delta variants have been identified with 22 assigned the names A.Y.1 to 22 and another as A.Y.3.1 and the other 4 are being studied still.
One of these sub-lineages, called Delta AY.12,
has all the characteristic Delta mutations except one.
It was reported that the spike in cases in Israel is of concern because it’s a country with nearly 60% of its adults fully vaccinated and reports that the Pfizer vaccine’s effectiveness in that country is significantly less than what emerged over clinical trials.
The Delta variant, the most widely prevalent variant of concern in India, is being “reclassified” to another sub-lineage that has been associated with a large number of cases in Israel, the India SARS-CoV-2 Genome (INSACOG) consortium, which tracks emerging variants, said in a report on Monday.
The INSACOG report noted, “The reclassification is primarily to assist micro-epidemiology and is not based on acquisition of significant mutations. Thus, it is not currently known whether AY.12 is clinically different from Delta. 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.”
Dr Anurag Agrawal, Director, CSIR-Institute of Genomics and Integrative Biology told Thailand Medical News, “The Delta variant, because of its preponderance in coronavirus cases globally, has several sub-lineages, making it necessary to reclassify them as not doing so would make naming them unwieldy. A large number of cases in Israel have been linked to AY.12. In India, there are several micro-lineages and some of them are AY.12. We need to wait and watch to see how significant this micro-lineage is in driving infections in India. But as of now, it has exactly the same risk classification, no more and no less, than Delta.”
A detailed and complete reclassification and estimating the prevalence of AY.12 in India is expected to take some time, according to the INSACOG. “Since the AY.12 definition is inconsistent, final numbers will take some time. AY.12 analysis will be added to the portal (a public website), along with other new lineages, once there is greater consensus,” their report noted.
To date, according to INSACOG, about 70,000 coronavirus samples have been sequenced for their genomic structure, of which 50,000 have been allotted to various lineages. About 60% of them consist of international variants of concern or interest (VoC or VoI) that are globally tracked and linked to outbreaks as well as instances of vaccine breakthrough and reinfections.
Within these VoC, the Delta variant comprises 70% of samples. The Delta plus cases, in which AY.12 is include
d, only number 67, though this is expected to swell after the reclassification.
Although the overall trajectory of daily cases in India is downwards, Kerala has reported nearly 31,000 cases on Wednesday, which accounts for nearly all of India’s caseload.
Some Indian researchers are claiming that the AY.12 sub-lineage has gain the right configuration to become more transmissible but this claim however warrants further studies.
A.Y.3 More Potent In Terms Of Causing Breakthrough Infections?
In another development, a research team from VA Boston Healthcare System, Boston University School of Medicine and Harvard Medical School has expressed concerns about the Delta variant’s A.Y.3 sub-lineage after it was found that transmission of the Delta Variant AY.3 could occur among fully vaccinated people even in a controlled environment of an inpatient medical-surgical ward.
The study team said, “It remains to be determined whether the Delta variant AY.3 lineage is more transmissible than the Delta Variant B.1.617.2. Our findings do raise concern that without stricter risk mitigation, nosocomial (originating in a hospital) transmission of the Delta variant and Delta sub-lineages will occur more frequently than with prior, less transmissible variants, even in vaccinated persons.”
The study findings were published on a preprint server and are currently being peer reviewed. https://www.medrxiv.org/content/10.1101/2021.08.05.21261562v1
While so called ‘experts’ are claiming that the Delta sub-lineages were purely created for epidemiological purposes only and to monitor cluster spreads and there is no cause for alarm, the fact is that each of these sub-lineages possess unique mutations, deletions etc that are showing different characteristics in terms of viral fitness, transmissibility, virulence to even pathogenesis. Further detailed studies are currently underway and in a few weeks times we should have more concrete published data on the uniqueness of each of these sub-lineages.
As Thailand Medical News had predicted earlier, we are no longer facing a single pandemic but rather, we are facing a few pandemics simultaneously as there are different classes of the same pathogen at play now, each with its own uniqueness.
For more on the Delta variant sub-lineages
, keep on logging to Thailand Medical News.