Omicron’s BA.2 lineage found in 82% COVID-19 samples in India

The BA.2 lineage of the Omicron variant has been found in nearly 82 percent of the samples examined from COVID-19 patients across the country over the last month, top sources in the government’s COVID genome sequencing network have told Moneycontrol.

Officials attached with INSACOG said that the proportion of BA.2 was 5 percent in samples subjected to genome sequencing in December 2021 as compared to BA.1 lineage, which was 8 percent.

This proportion, however, grew sharply over the next few weeks, and collectively BA.1 and BA.2 were found in over 95 percent samples subjected to whole-genome sequencing in most cities.

The information assumes significance in the wake of the World Health Organisation issuing a fresh statement on February 22 which said that based on the available data of transmission, severity, reinfection, diagnostics, therapeutics, and impacts of vaccines, BA.2 sublineage should continue to be considered a variant of concern.

The statement was based on the recommendation of the WHO's Technical Advisory Group on SARS-CoV-2 Virus Evolution which had discussed the latest evidence on the Omicron variant of concern, including its sub-lineages BA.1 and BA.2.

When the Omicron variant started sweeping the countries including India in late 2021, outcompeting other COVID-19 virus variants such as Delta, it was BA.1 lineage that was the most dominant, however, it is now being taken over by the BA.2 lineages in most places.

But the scientists attached with INSACOG now stress that as BA.2 is already the most dominant COVID-19 virus variant in India, there may not be any immediate threat of a fresh surge in infections, unless a new variant surfaces.

In the country, the daily COVID-19 infections during the Omicron wave, have been falling after reaching a peak of nearly 3.7 lakh on January 21 this year and have now come down under 20,000 every day. Similarly, there has also been a dramatic fall inactive cases since the last week of January and it is currently below 2 lakhs.

This wave in India, however, has remained distinct from the last two waves with far lower rates of hospitalization and deaths.

Researchers say that Omicron is made up of several sub-lineages, of them, the most common ones are BA.1, BA.1.1, and BA.2. At a global level, the proportion of reported sequences designated BA.2 has been increasing relative to BA.1 in recent weeks, however, the global circulation of all Omicron variants is reportedly declining.