(ORDO NEWS) — The XBB.1.5 coronavirus subvariant currently accounts for about 28% of COVID-19 cases in the US. The U.S. Centers for Disease Control and Prevention (CDC) predicts that the prevalence of the subvariant will increase worldwide.
Whether the new option will cause a new wave of hospitalizations or humanity is already sufficiently protected is not yet clear.
It seems that we have already forgotten about the pandemic, but it has not gone anywhere yet. Although it seems to have become less lethal
The XBB.1.5 subvariant currently accounts for about 28% of U.S. COVID-19 cases, and the U.S. Centers for Disease Control and Prevention (CDC) predicts that XBB 1.5 prevalence is increasing worldwide.
In the northeastern United States, the sub-variant quickly supplanted numerous other variants that were expected to circulate this winter.
“XBB.1.5 will almost certainly dominate the world. I can’t find any competitor now. Everything else is incomparable,” Yunlong Cao, an immunologist at Peking University in Beijing, whose team is studying the properties of XBB.1.5 in the lab, tells Nature.
Scientists warn that the impact of XBB.1.5 in the US and the world is still far from clear. This option may not cause a large spike in infections or hospitalizations in many countries due to the high immunity created by exposure to earlier waves of COVID-19 and vaccinations, especially recent boosters for those most at risk of severe illness.
However, even if XBB.1.5 does not cause large waves of COVID-19, it will be important to closely monitor its development, the researchers say.
The subvariant carries a rare mutation that can increase its infectivity and create the possibility for further changes that will be extremely dangerous.
Great-grandson of Omicron
As the name suggests, XBB.1.5 is an offshoot of a variant of SARS-CoV-2 called XBB. This line is a recombinant of two descendants of the BA.2 line, which peaked in early 2022. Variant BA.2, in turn, is an offshoot of Omicron.
The XBB spike protein has a set of mutations that increase the variant’s ability to evade antibodies. This has helped XBB spread over the past few months, especially in Asia, where it has caused a spike in cases in Singapore.
Variant watchers spotted XBB.1.5 in late 2022 thanks to a rare amino acid substitution called F486P in the spike protein.
Experiments in Cao’s lab show that the mutation improves the variant’s ability to attach to the human ACE2 receptor, which SARS-CoV-2 uses to enter cells. Importantly, the mutation does not appear to impair the ability of XBB to elude antibodies.
“XBB is really bad at binding to ACE2,” Cao says, and the F486P change introduced in XBB.1.5 helps overcome this shortcoming.
The CDC estimates that XBB.1.5 is the second most common variant in the United States, accounting for 28% of cases nationally and over 70% in the Northeast.
The number of cases of this variant is doubling roughly every week in the United States, and slightly slower in other countries where the variant has appeared.
This is comparable to the rate at which BQ.1 and BQ.1.1 options rose in September 2022, but slower than earlier Omicron waves.
Although it looked like the BQ.1 and BQ.1.1 would make big waves, they quickly fizzled out, only appearing in Europe and North America.
If the same happens to XBB.1.5, other variants will gradually replace it without causing a large increase in infections.
But all researchers agree that XBB.1.5, like its predecessor XBB, is a master of immunity evasion. It carries numerous spike mutations that blunt the activity of antibodies resulting from vaccination and infection.
Throughout 2022, researchers have observed how different Omicron lines “learn” to overcome the immunity gained from vaccines and previous waves.
And as global immunity to XBB.1.5 builds up, the evolution of the coronavirus will not stop, says Yunlong Cao: “We will still see many new mutations that have never been seen before.”
Contact us: [email protected]