A new Delta ‘Plus’ variant of the coronavirus, which is said to be driving a surge in Covid-19 cases in the UK and parts of Eastern Europe, has shown up in India and a group engaged in the genome sequencing of the virus is already monitoring it.
So far only 20-30 cases – or less than 0.1% of the cases sequenced in India – have been identified with the AY.4.2 sublineage of the Delta variant, according to scientists at INSACOG, a consortium of leading Indian institutes engaged in SARS-COV 2 genome sequencing.
They don’t see this as a cause for concern yet.
This number is “too low to be a current problem”, said the lead scientist at INSACOG, Anurag Agarwal of the Institute of Genomics & Integrative Biology. It is also too early to conclude whether the sub variant does have a real growth advantage or is a “better” version of the Delta, he said.
First spotted in July this year in the UK, more than 15,000 cases of the AY.4.2 have been reported in that country so far. Last week, the UK termed it “variant under investigation”. UK reports have indicated a “growth rate of 17% for AY.4.2 compared to other circulating variants” and a “secondary attack rate” of 12.4% for household contacts compared with 11.1% for Delta.
It has been spotted in 33 other countries as well, but mostly in lower numbers. The US government’s Centre for Disease Control has counted fewer than a dozen cases of AY.4.2 so far.
The Delta variant continues to be the dominant variant of concern in India and the world over, but a close watch is being kept on all new variants and sub lineages.
Agarwal said the sub variant was under close watch at INSACOG labs even with its low numbers, but also pointed to poor identification of it so far.”Its definition is not fixed yet … there is not very much to identify it yet,” he said.
Agarwal also pointed out that as would be the usual trajectory, Delta cases with the old/original version were now falling and modified versions were coming in. More than 30 sublineages of the Delta are already being counted.
However, he said none of the new ones was consistently faster in transmission or fitter than the Delta variant, as per data available so far.On reports of more children being affected by the sub variant in the UK, Agarwal pointed to their vaccination status.
“Children are the least vaccinated and so likely to be infected, but there is no clear evidence as such vis-a-vis this sub variant yet,” Agarwal told ET.
A technical briefing of the UK Health Security Agency issued on October 22 said AY.4.2 accounted for a “slowly increasing proportion of cases in the UK”. It is present in several countries, but its origin is not yet known, it said.
The UK agency further said that the AY.4.2 had a “modestly increased growth rate” in comparison to Delta and this could be due to a biological change in the virus (transmissibility or immune escape) or to epidemiological context, such as being introduced into an area or population subgroup with high existing levels of transmission.
The AY.4.2 is distinguished by two key spike mutations – A222V which is seen across most Delta lineages but also Y145H. It is Y145H which is closely being assessed for any additional impact on the characteristics of the variant.Internet Explorer Channel Network