As per the genome sequencing data for Pune city, 100% of the samples sequenced by the Indian Institute of Science Education and Research (IISER) have tested positive for the Omicron variant of the SARS-CoV-2 virus which causes Covid-19. A month ago, most of the samples tested positive for the Delta sub-lineage which was fast replaced by Omicron, the primary variant driving the third wave numbers. Experts now believe that since the second half of January, the BA.2 variant has become completely dominant and whether or not and how these mutations affect the severity of symptoms and the transmission rate is yet to be studied.\
In plotting the number of samples sequenced at the institute and the sub-lineage reported by the institute, while the sub-lineage of Delta, AY lineage, was the most dominant strain in the samples up until mid-December 2021, Omicron fast started catching up and within a month, became the dominant strain. December 2021 and January 2022 saw a surge in the third wave when more new Covid-19 cases were reported, and Omicron was reported to be the primary variant. Within a few weeks, it was reported that Omicron, too, was mutating and reporting multiple sub-lineages such as BA 1 and BA 2. According to experts at IISER, Omicron has completely taken over since mid-January and 100% of the samples sequenced in the week between January 16 and 22 were Omicron and experts have now said that the BA.2 sub-lineage of the variant is the most dominant one currently.
Dr Krishanpal Karmodiya, lead scientist involved with the genome sequencing, said, “Currently, Omicron’s BA.2 is completely dominant. It is everywhere including in the hospitalised cases and also at our homes. However with the numbers going down, we do not think it is more transmissible or requires any specific change in treatment as there appears to be no specific change in the symptoms. There has been a drop in the number of cases currently and so, it would be too early to comment on the picture in February however we can say that in January, BA. 2 was the dominant strain.”
Although Omicron did drive the numbers, the data also showed that Delta and its sub-lineages continued to remain significant in the city’s samples up until the end of December 2021 for samples sequenced at the IISER laboratory.
