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in collaboration with
Dr Gérald Kierzek (Medical Director of Doctissimo)
Medical validation:
January 05, 2023
The XBB.1.5 variant, resulting from a recombination of two Omicron variants, is about to become the majority in the United States. What do we know about virulence? And its contagiousness? Answers with Dr Gérald Kierzek, emergency doctor and medical director of Doctissimo.
The XBB.1.5 is progressing rapidly
XBB.1.5 is a mutated version of Omicron XBB (a combination of two existing variants) first detected last summer in India.
With additional mutations, such as F486P, this strain seems to more easily circumvent human immunity and therefore antibodies against Covid-19 (made naturally or in response to vaccination).
Result ? This sub-variant progresses faster than previous Omicron variations.
“This is the first time that a recombinant has taken up so much space in a Western country“, notes with the Parisian, Samuel Alizon, research director at the CNRS and specialist in evolutionary biology.
And for proof: in just a few weeks, the XBB.1.5 has invaded the United States. It would thus represent nearly 40.5% of Covid cases as of December 31, 2022, according to estimates by the Centers for Disease Control and Prevention.
This derivative of XBB, cousin of BF.7 and BQ.1.1, has also been spotted in the United Kingdom, Germany, the Netherlands, Spain, Ireland, Australia, Singapore, India… and in France – where it is in the minority.
Possibly increased contagiousness
Another particularity of XBB.1.5: its contagiousness.
If this mutated version ofOmicron seems to penetrate more easily into our cells, it is because it has an additional characteristic:
“XBB.1.5 has a particular mutation that allows it to bind more easily to ACE2 receptors. On the other hand, if it seems more contagious, it is not more virulent than the previous variations of Omicron. Omicron’s symptoms otherwise remain mild. Only fragile populations need to be more vigilant“, recalls Dr Gérald Kierzek.