Omicron now accounts for over 90% of cases in Indian metros

Omicron Genome sequencing data by the Indian SARS-CoV-2 Genomics Consortium (Insacog) has shown that Omicron has become the predominant variant of the coronavirus in metropolitan cities accounting for more than 90% of cases in the country, people in the know told ET.

Data shows that Omicron has been spreading. According to the genomic surveillance data by Insacog network, in the fourth week of December, Omicron was found in 50% of the sequenced samples. In the second and third week of January, it has crossed over 90-95% in all isolated samples.

The Insacog genomic surveillance data showed that Omicron has been found in 100% cases in Rajasthan, followed by 90% cases in Delhi, 80% in Maharashtra, 70% in both West Bengal and Karnataka.

"India is a big country and while Omicron is dominant in India as a whole, we cannot say Omicron has completely replaced in all regions of India. However, by early January 2022, in big metros like Mumbai and Delhi, we can see such replacement," said Anurag Agrawal, director, CSIR-IGIB, who is a part of the Insacog.

Agrawal says replacement from Delta to Omicron is likely to spread in the country in the next few weeks.

"The replacement is expected to spread to smaller cities, which seems to have happened by mid-January in many tier-2 cities, and subsequently to tier 3-cities, rural and less connected parts of India. I expect that to happen over the next few weeks," he said.

However, according to him it is unlikely though that Delta will completely get replaced, since Omicron does not have much transmission advantage over Delta in unvaccinated and previously uninfected people.

In some places though Delta still accounts for 20-30% of all cases. "Such populations, where Delta can theoretically successfully compete with Omicron, are small in India, but very much there," he said.