The Omicron variant of the coronavirus is in the community transmission stage in the country and has become dominant in several metros where new cases have been spiking exponentially, INSACOG said in its latest bulletin.
Short for Indian SARS-CoV-2 Genomics Consortium, INSACOG checks variations in coronavirus across the nation to help understand how it spreads and evolves, and to suggest the best possible public health response.
The centre's Covid research body also said BA.2 lineage, an infectious sub-variant of Omicron, has been detected in a considerable fraction in India.
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, INSACOG said in its January 10 bulletin that was released on Sunday.
"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.
India's daily Covid curve showed marginal improvement today as the country reported 3.33 lakh cases, which is marginally lower than yesterday. With a tally of 3.92 crore cases, India is the second worst-hit country after the US.
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 rapidly.
"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.
A total of 1,50,710 samples have been sequenced and 1, 27,697 samples have been analysed so far by INSACOG.