BA.2.75.2 Variant: What We Know About ‘Centaurus,’ Vaccines
SHealth officials warned since the COVID-19 outbreak that the main obstacle to controlling this virus was its potential to evolve into more deadly and infective forms.
A new subvariant of Omicron, BA.2.75.2 is the latest to alarm. It’s already gained the ability to evade the immunity provided by current vaccines and can’t be neutralized by many of the antiviral drug treatments available. The strain has already been identified in 47 countries, and 39 states in the United States, which still account for less than 1 percent of all COVID-19 cases.
Here’s what we know so far about BA.2.75.2.
From where did BA.2.75.2 originate?
BA.2.75.2 is a subvariant of BA.2.75 and its name suggests that it was created. It’s growing quickly, particularly in India—although BA.2.75.2 accounts for only 0.5% of cases so far around the world. Because it shares many similarities with the existing subvariant, the World Health Organization has not designated BA.2.75.2 as a new variant but singled it out as an “Omicron subvariant under monitoring,” which means that health officials should prioritize tracking cases in order to hopefully prevent surges in infections. After a Twitter user suggested the name Centaurus to it, some experts call it Centaurus.
Public Health Officials are concerned about the BA.2.75.2
BA.2.75.2 is now carrying three more mutations of BA.2.75, wherein the virus attaches to cells to cause infection.
According to one study by Swedish researchers published Sept. 16 as preprint—meaning the research has not yet been peer-reviewed—these aberrations are helping BA.2.75.2 evade all of the currently available antibody treatments authorized by the U.S. Food and Drug Administration except for one: bebtelovimab. This monoclonal antibody treatment, made by Lilly is administered as an intravenous infusion to patients with moderate-to-severe COVID-19 symptoms and at risk for developing more serious disease. But because the drug targets only a specific portion of the virus’ spike protein, there’s no guarantee that the virus won’t develop mutations to evade it, too.
September 7, 2009 in New England Journal of MedicineJapanese scientists had slightly better results with BA.2.75 than other available treatments. They too found that bebtelovimab could neutralize the variant, and also reported that some of the first antiviral treatments developed—remdesivir and molnupiravir—as well as the latest one, Paxlovid, also remain effective.
Health officials worry that resistance to BA.2.75.2 is an inherent feature. According to the Swedish researchers, virus-fighting antibodies from blood donors who had recently been infected or vaccinated against SARS-CoV-2 were found five times lower than those of Omicron, which is currently the dominant Omicron variant. The scientists also discovered that BA.2.75.2 was not resistant to Evusheld, an antiviral combination treatment. Taken together, the scientists concluded, this variant “effectively evades the current [antibody] immunity in the population” and “represent[s] the most resistant variant characterized to date.”
Is it possible to get vaccines that work against BA.2.75.2
The picture at the moment is not complete. Human studies of the latest COVID-19 booster shot—which targets two other Omicron subvariants, BA.4 and BA.5—have not been finished yet, and it’s not clear how effective they will be against BA.2.75.2, either. However, there is some evidence from the original vaccine that suggests what level of protection one might get if this variant spreads.
David Montefiori, a viral immunologist at Duke University Medical Center who oversees testing of Moderna’s mRNA vaccine’s effectiveness against new variants, is now studying how blood samples from people immunized with Moderna’s vaccine stand up against BA.2.75.2. These results are similar to those obtained in previous studies against BA.2.75. A correspondence was published in New England Journal of Medicine on Sept. 9, he and his team reported that while levels of virus-fighting antibodies against BA.2.75 were more than four times lower than levels against the original virus among people vaccinated with Moderna’s shot, they remained effective. However, BA.2.75.2’s three additional mutations “could potentially make the virus less sensitive to neutralization,” he says, “but we have to test it and find out.” Results from those ongoing studies, funded by both Moderna and the National Institutes of Health, are expected in October.
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