Even as BA.4 and BA.5 continue to climb the charts, crowding out earlier Omicron subvariants, scientists are warning about an even newer strain: BA.2.75.
Tom Peacock, PhD, a virologist at Imperial College London, tweeted on June 30, “worth keeping a close eye on BA.2.75 — lots of spike mutations, probable second generation variant, apparent rapid growth and wide geographical spread.”
It’s a quickly spreading variant with a host of spike mutations appearing together, but scientists say it’s still too soon to know for certain exactly how much better — if at all — BA.2.75 is at escaping natural and vaccine-induced immunity.
Here’s what we know so far about the newly mutated descendent of BA.2:
Where Is It Spreading?
So far, the subvariant has made its way to at least 10 countries in Asia, Europe, North America, and Australia.
BA.2.75 was first detected in India in early May and has been spreading quickly since. It made up almost 25% of samples there as of June 2 and is competing with BA.5 and BA.2, according to Katelyn Jetelina, PhD, MPH, an epidemiologist at the University of Texas School of Public Health in Dallas.
A more recent analysis of coronavirus sequencing, posted by a scientist in Australia, suggested the proportion of cases has jumped much higher as of July 8 — growing to nearly half of COVID cases sequenced in India.
A CDC spokesperson confirmed in an email to MedPage Today that there have been two cases of BA.2.75 detected in the U.S., with the first specimen collected on June 14. This is still not enough to get on the CDC’s variant tracker, where it is still unlisted.
Is It More Transmissible?
The BA.2.75 lineage has “9 unique changes in the spike protein,” according to a Twitter thread from Vinod Scaria, MBBS, PhD, principal scientist at the CSIR Institute of Genomics & Integrative Biology in New Delhi.
One mutation, G446S, is in the part of the spike protein that binds to receptors in our human cells, and is “associated with major immune (Ab) escape.”
Scaria also noted that while the number of genomes available to examine in India are still very small, “the rapid increase in recent weeks … suggest it might have a growth advantage.”
However, Marc Johnson, PhD, a professor of molecular microbiology and immunology at the University of Missouri’s school of medicine, said in an email to MedPage Today that “we don’t really know if BA.2.75 is more transmissible or more severe at this point.”
“What we do know is that it has amino acid changes that allow it to evade particular neutralizing antibodies,” he added.
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