The recombinant Omicron XBB.1.5 variant is the most transmissible sub-variant of Covid-19 to date and threatens to become the dominant strain in Europe “within one to two months”.
XBB.1.5 reminds us again that the Covid-19 pandemic is far from running out of steam. This recombinant variant of Omicron, which is currently surging in the United States, is to date the most transmissible sub-variant.
It threatens to become the dominant strain in European countries, including France, “within one to two months”, according to the European Union health agency (ECDC).
• What is its origin?
Subvariant XBB.1.5 is descended from XBB.1, itself descended from XBB which is a recombination of BJ.1 and BA.2.75. To put it simply, it is the result of two sub-variants of Omicron, the majority variant in many countries around the world.
“XBB.1.5 is very similar to its predecessor, XBB.1, but has an additional mutation of its spike protein, the famous key to entering the virus,” Grace Roberts, a virologist at the British University of Leeds.
• Is it more contagious and more dangerous?
It is the most transmissible sub-variant to date, said this week Maria Van Kerkhove, WHO technical manager on Covid. It clearly has a “growth advantage”.
The most likely explanation for this advantage is the spike protein mutation, which comes on top of a recombination of an already highly transmissible strain, the European Union health agency (ECDC) said. In the United States, XBB.1.5 is currently spreading 12% faster than other variants in circulation.
However, “there is no data to suggest that XBB.1.5 is more harmful – in terms of serious illness and death – than the previous variants,” said Grace Roberts. However, the WHO continues to assess the data.
ECDC said the overall risk level of the subvariant remains low for the general population. However, the risk is “moderate to high” for vulnerable people, such as the elderly or unvaccinated.
• Where does it circulate the most?
This subvariant was first detected in the United States in October and now accounts for more than 27% of infections in the country, according to the Centers for Disease Control and Prevention’s (CDC) variant tracker.
A total of 38 countries have reported cases of XBB.1.5, including 82% in the United States, 8% in the United Kingdom and 2% in Denmark, the World Health Organization (WHO) said in an assessment on Wednesday. rapid risk.
The ECDC said this week that XBB.1.5 currently represents only 2.5% of cases in Europe. But the agency’s mathematical models, based on the growth rate of this subvariant, show that it could become the dominant strain in Europe “within one to two months”, she said. friday.
• Is it progressing in France?
According to Public Health France, in his last point“XBB.1.5 seems to be circulating quietly in mainland France. It was initially detected during Flash S48-2022 (early December) and has since remained at low levels (less than 1%)”.
The majority sub-variant in France is still BQ.1.1, also from the Omicron family (and even sub-lineage of BA.5), but it could therefore run out of steam in favor of XBB.1.5 in the weeks coming.
