As subvariant BA.5 of the Omicron coronavirus rages across the United States — accounting for an estimated 54 percent of cases in the country — experts have kept their eye on another subvariant threatening to follow closely on its heels.
The subvariant is designated BA.2.75 and was first spotted in India in late May. Against the backdrop of the BA.2 and BA.5 circulating in India, newcomer BA.2.75 began gaining ground quickly in June. It arrived this week
23 percent of recent virus samples
there. Meanwhile, BA.2.75 spread beyond India’s borders. It is now available in
about 10 other countries
including the US, according to the World Health Organization.
are experts affected about the new subvariant, not only because of its rapid rise. It has several mutations in its spike protein– the critical protein that allows the virus to attach itself to human cells and the protein that acts as the primary target for immune responses. BA.2.75 in particular has key mutations that suggest it could be good at it evade antibody responses in individuals vaccinated and/or previously infected with previous omicron subvariants.
“This subvariant seems to have some mutations in the receptor-binding domain of the spike protein, so obviously that’s a key part of the virus that binds to the human receptor, so we need to monitor that,” Dr. Soumya Swaminathan, the World Health Organization’s chief scientist said in an explainer video this week.
Swaminathan notes that for now, the number of samples and sequences is still small and our understanding of this version of the virus is limited. “It is too early to know if this subvariant has additional immune evasion properties or is actually more clinically serious.” We do not know that. So we’ll have to wait and see,” she said, adding that it’s monitoring the subvariant closely.
US situation
So far, three cases of BA.2.75 have been detected in the US, identified in California and Washington state. Helix — a California-based virus surveillance company that works with the Centers for Disease Control and Prevention to track emerging coronavirus variants — confirmed Ars’ third case in the United States in an email on Friday. Samples for the three US cases were collected on June 14, June 15 and June 27.
According to Helix, it’s still too early to predict how BA.2.75 will play out in the US, but it’s worth keeping an eye on the subvariant – reflecting warnings from outside experts.
Meanwhile, BA.5 conquers the USA. The prevalence of the previously reigning omicron subvariant BA.2.12.1 has fallen to an estimated 27 percent. BA.4 — a subvariant that shares the same spike mutations as BA.5 and has spread elsewhere alongside BA.5 — appears to have stalled, accounting for just 16.5 percent of US cases.
Amid the rise of BA.5, cases have maintained a high plateau, although many cases detected by rapid at-home testing go unreported. Corresponding Tracking by the New York Times, the country is recording an average of around 108,000 new cases per day. Some pundits are anxiously waiting to see if there will be a bump after the Independence Day celebrations. Just before the holiday, the positivity rate of the reported tests reached a worrying 17.5 percent.
Elsewhere, daily hospitalizations have risen 15 percent over the past two weeks to an average of 35,651. Admissions to intensive care units have also increased by 16 percent. The number of deaths remains at around 320 a day.
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