Omicron sibling BA.1 dominating, replacing Delta in India: Scientists

PUNE: Scientists working on genome sequencing of positive clinical samples have said that along with the original Omicron (B.1.1.529) variant, its sibling (sub-lineage) BA.1, is dominantly co-circulating and rapidly replacing the Delta variant in Maharashtra and some other states.

BA.1 with its growing prevalence and with some defining mutations of the original Omicron strain is highly transmissible and is the main force in the current surge across the country. So far, most patients have shown very mild illness and comparatively less need for hospitalisation.

The Omicron variant has three sub-lineages, BA.1, BA.2 and BA.3, along with the original Omicron strain. Sub-lineages BA.1 and BA.3 have a deletion at the amino acid position 69-70. “In some sequencing run of clinical samples, we get to see the presence of more BA.1 sub-lineage now than the original Omicron strain. Since the sub-lineage belongs to the same family, these samples are considered Omicron positive,” a senior scientist at the department of biotechnology told TOI.

The department’s Indian SARS-CoV-2 Genomics Consortium (INSACOG) reports genomic surveillance of SARS CoV-2 through sequencing of samples from sentinel sites and puts out a detailed district analysis for some states, including Maharashtra and Kerala.