A new variant of Sars-Cov-2 makes its appearance on the international scene. It was discovered in South Africa by the same group of scientists who first detected Omicron, and has already been identified with the acronym Ba.2.87.1. It is a hypermutated variant: in fact it presents over 100 mutations, of which more than 30 in the Spike protein, the experts on X highlight.
The new lineage
“8 genomes of a new Sars-CoV-2 lineage, with more than 100 mutations, have been deposited from South Africa. This is probably the most divergent lineage identified this year,” he explains Tulio de Oliveira, director of the Center for Epidemic Response and Innovation at Stellenbosch University, who identified it. The researcher illustrates some main characteristics of the new lineage, originally labeled Ba.2.X. The variant was detected between mid-September and mid-November 2023: “it is genetically distinct from the currently circulating Omicron lineages (in particular BA.2.86 and JN.1) – writes de Oliveira – and initial analysis suggests that it probably emerged from Ba .2 or from the basal node of Omicron”.
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How was it born? “The most plausible hypothesis, as in the case of Ba.2.86, would be a chronic infection followed by transmission in the population, in which it circulated undetected. However, we cannot also exclude the hypothesis of an animal reservoir,” explains the ‘expert.
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In South Africa infections remain low
“The degree of transmissibility and pathogenicity are still unknown – continues de Oliveira – To determine how widespread this new lineage is, South Africa has increased genomic surveillance, and at the moment there are very few signs that it is spreading widely and can replace the current dominant variant JN.1”. Ba.2.87.1 is not a concern for now. In South Africa, where it was discovered and has been circulating for some time now, infections remain low. Furthermore, “preliminary analyzes indicate that Ba.2.87.1 is less immunoevasive than Jn.1. It must produce additional mutations to remain competitive”, notes Raj RajnarayananNyitcom researcher and associate professor at the University of Arkansas.
A variant to keep under control
But it’s always good to keep your guard up. The new variant “is still part of the Omicron family and seems to derive from Ba.2, it absolutely needs to be monitored and kept under control. We hope it does not become prevalent”, explains the epidemiologist Massimo Ciccozzi. The De Oliveira center, the same one that took over Omicron, is “a very important genomic surveillance center in South Africa, perhaps the most important in the world”, adds Ciccozzi.
According to the expert, Ba.2.87.1 “is an interesting variant because it has many mutations, more than 100, but what is striking is that of these hundred at least 32 appear to be on the Spike protein”, the key that allows the entry of the viruses in cells. “Not only that. These are non-synonymous mutations – explains Ciccozzi – that is, there is the replacement of one amino acid with another which is totally different. This indicates an important evolution of the virus. Furthermore, the variant has 7 deletions, so precisely the pieces of the virus: 3 are on the Spike protein and 2 of these 3 have at least a deletion of 10 important amino acids on the segment that serves for antibody recognition. This is also part of the evolution of the virus, which sacrifices part of itself in order to evade the immune system. Deletions are, therefore, extremely more important than even non-synonymous mutations. In short, the new lineage of Sars-Cov-2 must be monitored and kept under control.”
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