As per experts, the BA.2.75, a new Covid-19 sublineage found in India, may fuel new infections. They claim it has unique mutations that increase the risk of infection in people who have previously been immune, and that broader genomic surveillance is required to better understand its epidemiology.
Shay Fleishon, from the Central Virology Laboratory at Sheba Medical Centre in Tel Hashomer, said in a series of tweets on Sunday that 85 sequences from eight countries had so far been uploaded on Nextstrain, an open-source platform of genomic data. The government has not yet confirmed the existence of the new sublineage. There were 69 of them from India, including – Delhi (1), Haryana (6), Himachal Pradesh (3), Jammu (1), Karnataka (10), Madhya Pradesh (5), Maharashtra (27), Telangana (2), Uttar Pradesh (1), and West Bengal (13).
It is still unclear, said experts, whether the new sublineage is more contagious. “We don’t know enough. As far as I’m aware, there are only a few sequences without any associated epidemiology,” University of Oxford virologist Shahid Jameel said.
According to Jameel, BA.2.75 has several spike protein mutations, two of which make it different from its parent strain BA.2.
“These are G446S and R493Q. G446S is one of the most potent sites of antibody escape from current vaccines that still neutralize BA.2. As a result, it increases the chances of infection in people who have previously been protected,” he stated.
While the numbers are still low, he believes the rapid increase indicates a “growth advantage” and that this may fuel fresh reinfections and keep the pandemic going.
According to Gautam Menon, professor of physics and biology at Ashoka University, it is too early to tell whether BA.2.75 has increased transmissibility and immune escape compared to BA.4 and BA.5, both of which appear to be dominant in much of the world. That said, it is certainly worth keeping a track of the spread of this variant in India.
The latest data from SARS-CoV-2 genome sequencing in the country has, however, shown that the BA.2 sublineage of the Omicron variant continues to be dominant.
On Friday, experts from the Indian SARS-CoV-2 Consortium on Genomics (INSACOG) will meet to review the data. So far, they have discovered that BA.2 is present in 85% of the sequenced samples. Other sublineages, such as BA.4 and BA.5, were found in less than 10% of the samples, whereas BA2.38 was found in 30% of the samples.