Yesterday, on October 25, a new ‘lineage’ of the Delta variant of COVID19 was identified from the positive samples collected across six states in India. Named as AY.4.2 , the mutated Delta variant has been found to be spreading fast in the United Kingdom (UK).

According to data uploaded on Global Initiative on Sharing Avian Influenza Data (GISAID) — an open access genomic database of influenza viruses, seven samples of AY.4.2 were found in Andhra Pradesh, four in Kerala, two each in Karnataka and Telangana, and one each in Jammu and Kashmir and Maharashtra.

Reportedly, it was first recognised towards the end of September, though it appears it surfaced in the UK around June.

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“The new delta variant seems to be highly transmissible but not fatal, as such. It can be more transmissible (or infectious) considering that the virus does that for its own survival as it needs more hosts (body of human being). However, it is difficult to say that it will be more virulent,” Samiran Panda Panda, head of Indian Council of Medical Research’s (ICMR) epidemiology department was quoted.

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Apart from India, which countries have reported AY.4.2?

As of now, of the total 18,207 cases of  AY.4.2 added to the GISAID database from across the world, 16,891 have been reported in the UK alone.

On October 20, AY.4.2 was designated a ‘Variant Under Investigation’ (VUI) by the UK Health Security Agency (UKHSA).

“The designation was made on the basis that this sub-lineage has become increasingly common in the UK in recent months, and there is some early evidence that it may have an increased growth rate in the UK compared to Delta. More evidence is needed to know whether this is due to changes in the virus’ behaviour or to epidemiological conditions,” UKHSA stated in its official news release.

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Although the UK is the top contributor of the AY.4.2 lineage of the Delta variant, it has also been found in Denmark and Germany in considerable numbers.

Apart from these three countries, it has also been found in isolated cases in the United States, Israel, Russia and now India.

Is AY.4.2 riskier or more transmissible than other Delta variants?

Available data from the UK suggests that other, pre-existing lineages of the Delta variant are far more infectious and deadlier than the newly found AY.4.2. 

However, the new lineage is in the spotlight because its number has been found to be on the rise. 

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“The AY.4.2 lineage has attracted attention because it has risen in frequency in the UK over recent weeks, now representing ~7% of all sequenced strains. It remains exceptionally rare anywhere else (only 2 strains found in the US so far),” Francois Balloux, Director of the London-based UCL Genetics Institute stated on Twitter on October 16. 

There are almost 55 sub-lineages of the Delta variant as of now.

“Delta had significant advantage over other lineages, in almost all regions, practically eliminating all other lineages as they spread widely. The continued evolution of delta provided a number of sublineages There are now ~55 sublineages (AY.1 – AY.41) of Delta,” Vinod Scaria, Scientist at the Institute of Genomics & Integrative Biology (IGIB) stated on Twitter on October 20.