She was nicknamed Centaurus and it worries virologists as it could become the cause of new waves. Omicron’s new sub-variant BA 2.75, first detected in India in early May, has now also been found in the UK and Europe, the US, Australia, Germany and Canada and is a “special observation” for the WHO. Centaurus appears to spread faster than the variant Omicron BA.5 and is rapidly replacing BA.2 (Omicron 2) formerly dominant in many countries.
Il 7 July the European Center for Disease Prevention and Control (ECDC) he called it a “monitored variant,” which means there is a suspicion that it may be more transmissible or associated with more serious diseases. However studies are still ongoing and there are no certainties about its greater contagiousness or danger.
Centaurus, why worry?
The variant Ba 2.75 presents 8 mutations of the Spike protein that distinguish it from Omicron 2 and 11 compared to Omicron 5 (the current most widespread variant in Italy, responsible for over 60% of infections). According to experts, this high number of mutations would increase the “immune escape“ie the possibility of the virus Covid to escape the immunity achieved with a previous contagion. In practice, it is possible to “reinfect” with the new variant even after a short time and this could trigger a new pandemic wave.
In India, then, this new sub-variant appears in competition with Omicron 5 and, according to some experts, the advantage over BA.5 could make this version of Covid even more contagious, at levels perhaps higher than those of measles.
«It is difficult to predict the effect of so many mutations that appear together: they give the virus a ‘wild card’ property in which the sum of the parts could be worse than the parts individually, ”explains Tom Peacock, a virologist at Imperial College London, who was the first to identify Omicron.
What will happen after Omicron
According to Peacock the subvariant Centaurus could “undermine BA 5 and become dominant ». Otherwise it could be a “taste” of what will happen in the coming months: the great ability of the virus to mutate could lead to the spread of “variants of a variant“generating new waves.
It wouldn’t be the first time the virus has surprised us. As Stephen Griffin, a virologist at the University of Leeds, observes: ‘Last year we were very convinced that Delta represented an evolutionary pinnacle for the virus, but the emergence of Omicron and the vast increase in the variability and evasiveness of antibodies is a a sign that we cannot, as a population, follow a flu-like plan to keep pace with viral evolution ”.
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