Delta sub-lineages unlikely to be more transmissible than parent variant: Government panel

NEW DELHI: Sub-lineages of Delta variant — AY.1, which is commonly known as the Delta Plus, and AY.2 — are unlikely to be more transmissible than the parent, said INSACOG, a consortium of government panel involved in genome sequencing of coronavirus.

These two sub-lineages are also below 1 per cent in the genome samples sequenced in the country in June, it said in a recent bulletin.

INSACOG also said AY.3 has been identified as a new Delta sub-lineage and it is defined by ORF1a: I3731V common AY.1 mutations except for S: K417.

This is primarily seen in the US with single reclassified cases in the UK and India.

However, there is “no known significant property” of this mutation.

But since it is a Delta variant of concern (VOC) sub-lineage, INSACOG will continue to monitor it, the bulletin stated.

“Delta sub-lineages AY.1 and AY.2 are declining globally with near-zero cases in the last week of June in either the UK or US, where they were most frequently seen.

They also continue to be below 1 per cent in available sequences from June in India.

“It is likely that neither AY.1 nor AY.2 is more transmissible than Delta,” the INSACOG said, adding there is no indication of a rising trend in the four clusters of Ratnagiri and Jalgaon in Maharashtra, Bhopal in Madhya Pradesh and Chennai in Tamil Nadu.

INSACOG said the Delta variant (B.1.617.2) is the dominant lineage for new cases across all parts of India in recent samples and remains the most rapidly rising lineage globally.

Delta variant and its sub-lineages are the only VOC in India at this time, it added.

It was a prime variant driving the second wave of the coronavirus that swept India between March to May this year, killing thousands and infecting lakhs.