Is Omicron 5 or Centaurus faster? Is the first or second variant more dangerous? In this late summer remnant, with autumn approaching and the variant with the bombastic name on the way, do we have to fear a new and amplified contagion effect? We immediately dispel the doubt, which is also the fear of many: the Sars-Cov-2 variant called Centaurus, is no more resistant to antibodies than the currently dominant omicron 5. To ascertain this is a study published in Lancet Infectious Diseaseswork that characterized the new sub-variant of Omicron BA.2.75, comparing its ability to evade antibodies against current and previous variants.
Covid, Centaurus ready to make thousands of infections: from September it will be dominant
by Donatella Zorzetto
The Swedish study
The tests were carried out using 40 blood samples collected at random in Stockholm, both before and after the first wave from Omicron. The assumption from which the initiative was born is that last May a new variant of Omicron, BA.2.75, was detected, which is leading a wave of infections in India and has spread internationally. And in recent weeks that mutation has also been detected in Sweden. “Identifying how vulnerable the population is right now to emerging variants is crucial,” he explained Daniel Sheward, researcher in the Department of Microbiology, Cancer and Cell Biology, Karolinska Institutet, and first author of the study -. By producing a pseudovirus for BA.2.75 we were able to test its sensitivity to antibodies present in blood donors. “
How long are the antibodies to the two variants?
The researchers also investigated whether antiviral monoclonal antibodies, which are used clinically to treat already infected patients, lose their effect against omicron BA.2.75, compared to BA.5. And the result of the research was comforting. “Our study shows that Omicron BA.2.75 has approximately the same level of resistance to antibodies as the dominant variant BA.5. It is reassuring news, should we experience a BA.2.75 surge,” by stressed Ben Murrellassistant professor in the Department of Microbiology, Karolinska Institutet, and senior author of the study.
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The research of Sassari
But there are those who have gone further. This is demonstrated by the study “On the SARS-CoV-2 BA.2.75 variant: a genetic and structural point of view”, carried out by researchers from the University of Sassari, in collaboration with the Campus Bio-Medico University of Rome and the Department of Biochemical Sciences of Sapienza University of Rome. To conduct the research, all genomes available in the public database Gsaid were analyzed, for the Centaurus variant and for the main lineage of the Omicron 5 variant, at the time of the analyzes. In particular, 700 viral genomes were used which required about 1,500 hours of computational computation to complete the genetic tests.
“Centaurus less dangerous than Omicron”
The analysis on Centaurus, published in the scientific journal Journal of Medical Virology, provides a genetic perspective by analyzing all available genomes and conducting the first evolutionary study of a philodynamic nature on this variant. What emerges in some ways is astonishing. Because Centaurus, hitherto feared for its alleged aggression, actually has a lower ability to evolve and expand than the Omicron 5 variant. Consequently, experts suggest, we shouldn’t worry. The study points out that, in light of current data, Centaurus “does not have characteristics compatible with one that has high expansion capabilities”. “These results have predictive value – he highlights Pier Luigi Fiori of the Department of Biomedical Sciences of the University of Sassari – because, in addition to allowing for the first time the identification of the moment in which Centaurus reached its maximum expansion peak, in the second half of June 2022, they currently indicate that in ‘immediate future will not be able to further expand its reach “.
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by Donatella Zorzetto
The map of variants in Italy
That the tug-of-war between Omicron and Centaurus cannot actually exist, or that in any case it has not yet begun, is testified by the percentage weight of the two variants in Italy today. Omicron appears to have an estimated prevalence of almost 100%, according to the extended weekly report of the Higher Institute of Health. Therefore, the sub-variant BA.5 is largely predominant, with a national prevalence of 90.8% (75.5% in the previous survey). The primacy of BA.5 is found in all regions, with a range between 76.5 and 100%. The ISS also notes “a significant increase in the number of BA.5 sub-lineages circulating in Italy.” And Centaurus remains under control, with few confirmed cases, although it has been circulating in Italy for about three months.
Three doses of vaccine also effective against Centaurus
Meanwhile, a third study also brings reassurances on another front: it attests that “vaccination with three doses offers a protective effect also against Centaurus, comparable to that obtained against the sub-variants BA.1 and BA.2 and greater than that against BA.5. The data emerges from the research of Duke University Medical Center in Durham and Moderna published in the New England Journal of Medicine. “BA.2.75 has recently emerged with a slow but alarming increase in prevalence,” explain the researchers. It is currently “monitored as one of the next potentially globally prevalent variants. The ability of BA.2.75 to escape vaccine-induced neutralizing antibodies is therefore of great interest ».
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The results from the serum of 20 volunteers
The team verified the ability of the antibodies developed after vaccination to recognize and neutralize the new variant using the serum of 20 volunteers who had received the booster dose of the Moderna vaccine for almost a month. It was found that vaccination has an efficacy against Centaurus that is completely comparable to that of BA.1 and BA.2 (slightly lower than B1.A, but higher than BA.2); the effectiveness is instead more than double compared to the sub-variant BA.5, currently dominant in the world. “Whether and to what extent – the researchers conclude – another vaccine booster, particularly one containing Omicron’s Spike protein, can elicit a more potent response against BA.2.75 and future SarsCoV2 variants remains at the center of our attention.”
