Bengaluru Apr 24 :With reports of one case each of two Omicron sub-variants Ba.2.10 and Ba.2.12 being found in Bengaluru, experts said there was no evidence to suggest they are more transmissible than Ba.2 Omicron variant.
However, as per data shared by a member of the state genomic surveillance committee, there have been 112 cases of Ba.2.10 and 77 cases of Ba.2.12 in Karnataka since March 1, 2022.
The member said the positivity rate in Bengaluru touched 3% on Saturday while it was 1% in Karnataka.
People want to blame it on Ba.2.12 and the XE variant. But there have been no XE cases in the city or in Karnataka. At this juncture, there is no data to substantiate that the R0 for the sub-variants is more than Ba.2 itself,’ the member told DH on the condition of anonymity.
R0, pronounced ‘R naught’, is a mathematical term that indicates how contagious an infectious disease is. It is also referred to as the reproduction number. It is the average number of infected contacts per infected individual.
‘That these two sub-variants are more transmissible is a wrong statement. Cases are increasing and there is a tendency to assume it is because of this. Since XE which is the sister concern has caused a surge in other countries, we are assuming that Ba.2.12 and Ba.2.10 are causing the surge here. Ba.2.12 has spike protein mutations,’ he said.
Another member of the committee said studies the world over weren’t indicating increased virulence.
As per data shared by the Karnataka Health Commissioner D Randeep, out of the 714 genome sequencing results since March 1 this year, 574 (82.70%) had the Ba.2 Omicron variant. Karnataka has not found the Ba.2.12.1 that was reported in Delhi.
A researcher from Genotypic Technologies, a Bengaluru lab that’s part of INSACOG (Indian SARS-CoV-2 Genomics Consortium) told DH, ‘These two sub variants are just Indian variations of the old Ba.2 Omicron variant. This is a variation of the existing variant. If this variant spreads, we will know in another one week.’
‘Even in Delhi which reports 1,000 cases, only 300 samples have viral load high enough that can be sequenced, which are done by government labs. No samples are sent to private labs for sequencing. In South India, the samples that can be sequenced are in double digit,’ he said.
A TAC member told DH , ‘This is yet to be officially confirmed by INSACOG, Delhi. Till then it is best to strictly comply with Covid Appropriate Behaviour and wait for official communication.’