COVID FAQ: ‘Closely Watching’ BA.2.75 Variant Detected in India Says WHO
Omicron subvariant BA.2.75 detected in India, has now been found in 10 other countries.
Scientists at the World Health Organisation have now confirmed that they are tracking a new potential subvariant, dubbed BA.2.75, closely.
Although the Omicron subvariants have proved to be more infectious but not more virulent than the previous strains of the virus, experts have maintained that a new variant with significant mutations could change the course of the pandemic for the worse.
If early evidence is anything to go by, Omicron's latest subvariant to be identified might just be it.
As cases of COVID once again see an upward trend in India (and the world over), experts have taken to the internet to flag BA.2.75, a subvariant of Omicron that was recently detected in India.
What has the WHO said about BA.2.75?
The WHO, on 6 July released a short video acknowledging the new subvariant. Speaking for the WHO, Chief Scientist, said that the variant has not been officially named, but is being called BA.2.75.
She went on to say, "there is still limited sequences available to analyse, but this variant seems to have some mutations on the receptor binding domain of the spike protein...we have to watch that."
How many countries have detected the subvariant so far?
In a series of tweets, Dr Shay Fleishon, with the Central Virology Laboratory at Sheba Medical Center in Tel Hashomer, said that so far 85 sequences of the variant have been uploaded to Nextstrain, an open source platform of genomic sequencing data.
The subvariant has so far been detected in 11 countries.
Apart from India, these include, UK, US, Germany, Japan, Canada, Australia, and New Zealand so far.
Where in India has BA.2.75 been detected?
69 of the 85 sequences of BA.2.75 uploaded to Nextstrain, were from 10 states in India. These are - Delhi, Haryana, Himachal Pradesh, Jammu, Karnataka, Madhya Pradesh, Maharashtra, Telangana, Uttar Pradesh, and West Bengal.
BA.2.75 is also hard to spot, which means the actual numbers are likely much higher than the sequencing data we have.
How is this subvariant different?
According to Dr Fleishon, "this is a 2nd generation for BA.2, saltation of 16 mutations, 8 are in S (4 in NTD, 4 in RBD including a reversion)."
According to researchers at Bloom Lab, a lab studying molecular evolution of proteins and viruses in the US, the subvariant has two major mutations of G446S and R493Q.
"G446S is at one of most potent sites of escape from antibodies elicited by current vaccines that still neutralises BA.2."Bloom Lab, US, on Twitter
They go on to add that although R493Q is not a major antigenic mutation, it does enable G446S, and increases BA.2.75's affinity to ACE2- the protein that hooks onto and infects human cells.
The WHO, in their official statement has also acknowledged that the mutations on this subvariant is one to be watched.
Can BA.2.75 evade vaccine protection?
Based on early evidence, experts believe so.
Omicron and its subvariants are known to circumvent vaccine protection as well as immunity from a previous infection.
According to Bloom Lab, a lab studying molecular evolution of proteins and viruses in the US, "BA.2.75 will have antibody escape that is similar to that for BA.4/5 with respect to the current vaccine.
Will BA.2.75 be the next dominant COVID variant?
In his Twitter thread, Dr Shay Fleishon says it's too soon to tell. "But," he also adds that BA.2.75 is to be watched, "because it may imply for a trend to come."
Is it a variant of concern?
While experts from around the world flagged this new subvariant last week, the world health organisation only acknowledged it officially on 6 July.
WHO's chief scientist Soumya Swaminathan said it was 'too early to say whether it can cause severe infections.’
She also, however added that the WHO is watching the data from around the world closely.
"At any time, if there is an emergance of a virus that looks very different from a previous one, enough to be called a seperate variant of concern, then the committee will do that."Soumya Swaminathan, WHO Chief Scientist
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