The Delta variant of Covid-19, first found in India, rapidly spread across the world this summer, emerging as the dominant variant globally...
The Delta variant of Covid-19, first found in India, rapidly spread across the world this summer, emerging as the dominant variant globally. But as it mutates further, it has now branched out into the AY sub-lineages, which have gradually started replacing the parent variant.
In the United Kingdom, where Covid-19 cases are on the rise, most samples sequenced recently have shown the presence of AY.4.2. What has caused some alarm is that this sub-lineage is 10-15% more transmissible than Delta and has mutations that help the virus evade an immune response in a previously infected or vaccinated person.
Genome sequencing in India, too, has shown a growing presence of Delta’s sub-lineages. Cumulative sequencing data till October 25 shows 5.7% of 1.07 lakh samples sequenced in India belong to AY sub-lineages. Until September end, AY lineage accounted for 3.4% of total sequenced samples.
In Maharashtra, where over 19,000 samples have been sequenced till October 25, available monthly data of variants shows the percentage of samples with the Delta variant shrunk from 73% in May to 68% in September. In the same period, the presence of AY sub-lineages rose from 13% to nearly 20% amongst all the variants.
The most common sub-lineages of Delta found in India are AY.33...
