The Omicron variant of COVID-19 is in the community transmission stage in India and has become dominant in multiple metros where new cases have been rising exponentially, the INSACOG has said in its latest bulletin.

It also said BA.2 lineage, an infectious sub-variant of Omicron, has been found in a substantial fraction in the country.

The INSACOG, in its January 10 bulletin that was released on Sunday, said while most Omicron cases so far have been asymptomatic or mild, hospitalisations and ICU cases have increased in the current wave and the threat level remains unchanged.

"Omicron is now in community transmission in India and has become dominant in multiple metros, where new cases have been rising exponentially. BA.2 lineage is in a substantial fraction in India and S gene dropout based screening is thus likely to give high false negatives," it said.

S-gene drop-out is a genetic variation like that of Omicron.

"The recently reported B.1.640.2 lineage is being monitored. There is no evidence of rapid spread and while it has features of immune escape, it is currently not a variant of concern. So far, no case has been detected in India," the INSACOG said.

The INSACOG, in its bulletin of January 3 which was also released on Sunday, also said Omicron is now in community transmission in India and has become dominant in Delhi and Mumbai where new cases have been rising exponentially.

"Further spread of Omicron in India is now expected to be through internal transmission, not foreign travellers, and a revised sampling and sequencing strategy of INSACOG is being worked out to address genomic surveillance objectives in the wake of dynamic changing scenario of virus infection," the INSACOG said.

"COVID appropriate behaviour and vaccination are main shields against all form mutations of SARSCoV-2 virus," it said.

The INSACOG, under the Union Ministry of Health and Family Welfare, reports genomic surveillance of SARS CoV -2 across the country through sequencing of samples from sentinel sites and also detailed state-wise district analysis for some states.

A total of 1,50,710 samples have been sequenced and 1, 27,697 samples have been analysed so far by INSACOG.