A new wave of Covid-19 is building as yet another variant - BA.5 - spreads around the country - it is expected to overtake the dominant BA.2 strain within weeks.
How contagious and how dangerous is BA.2.75?
Early evidence from overseas suggested the new 2.75 subvariant had some characteristics that may enhance its ability to evade immunity similar to the BA.4 and BA.4 subvariants and BA.2.75 may be more transmissible than BA.2, the Ministry of Health said.
"There is no current evidence that it leads to more severe disease, although assessing the evidence is at a very early stage," the ministry said.
The Seattle-based Bloom Lab which studies the molecular evolution of proteins and viruses said in a tweet that BA.2.75 was "worth tracking", as it had "appreciable antigenic change" compared to its parent variant BA.2.
It said there were two key mutations - G446S and R493Q.
Shahid Jameel, senior research fellow at Green Templeton College in Oxford University, told Business Standard that he believed G446S was one of the likely sites of escape from antibodies made by current vaccines that still neutralised BA.2. This would increase the chance of infection even in people who have so far been protected against Omicron, he said.
Indian microbiologist Dr Rajesh Karyakarte told Indian Express that "BA.2.75 has a distinct growth advantage over BA.4 or BA.5".
But there was no evidence to indicate that the variant caused a more severe form of infection, he said.
The Ministry of Health said it regularly assesses evidence on the latest variants and at this stage there was no evidence that BA.2.75 required a shift in public health settings already in place to manage Omicron.
How widespread is BA.2.75
The Times of India yesterday reported that BA.2.75 had been detected in about 10 states in India.
However it said the Indian Health Ministry and the genomic surveillance organisation, Indian SARS-CoV-2 Genomics Consortium, were yet to officially confirm the detection of the subvariant in India.
Outside of India, BA.2.75 cases have now been detected in New Zealand, Australia, Canada and Germany.
Melbourne-based data integration specialist Mike Honey said BA.2.75 was an "evolutionary jump" from BA.2.
It was prevalent in India where it had a very high growth advantage of 16 per cent per day above other Omicron BA.2 lineages, Honey tweeted.
