With the resumption of Covid-19 contaminations, three elements worry scientists: an influenza epidemic which could be stronger, with the risk of a “double epidemic”, an insufficiently followed Covid booster vaccination campaign and the arrival of new variants, more virulent.
On this last point, the variant XBB is closely monitored. If it does not concern France for the moment, it could be about to spread to Europe. “In Australia, it now accounts for 5% of sequenced samples, with very rapid and very recent growthcomments epidemiologist Antoine Flahault to The Midi Dispatch and the first cases have been observed in Europe, in particular in Denmark, and in the United States, where it could be likely to impose itself and potentially replace BA.5, which is for the moment mostly.
New XBB variant could bypass the immune system
Discovered in Singapore in September 2022, the XBB virus is “descended from a combination of two sub-lineages of Omicron”, says Antoine Flahault. This new strain has mutated, and is now endowed with five characteristic mutations Who “allow the sub-variants that have it to further circumvent acquired immunity to counter the attachment of the virus to our cells”, he continues. In other words, it means that XBB could infect our organism more easily and would be “one of the known variants of SARS-CoV-2 that best manages to escape acquired or vaccine immunity”adds the epidemiologist.
Could this new variant be resistant to vaccination? Despite their concern, the researchers remain confident about vaccine immunity to reduce the risk of a severe form and there is currently no evidence indicating the severity of this new variant. “Cell-mediated immunity – the one that allows our body to fight against severe forms of Covid – is not, to our knowledge, circumvented by these new variantsreassures Professor Flahault. Vaccines, mono and bivalent, should therefore continue to protect us effectively against the risks of hospitalization and death linked to Covid..
And in France, where are the variants?
In France, whether in metropolitan France or in the overseas territories, the variant Omicron is still dominant, with 100% interpretable sequences to September 19, 2022.”Within the Omicron variant, the BA.5 sub-lineage is now the majority: it represented 91% of the interpretable sequences of the Flash survey of 09/19/2022“, indicates Public Health France in an analysis published on October 5. BA.5 also remains in the majority internationally.
Two other Omicron sub-variants continue to circulate:
- THE BA.4 sublineage which represents 5% of interpretable sequences in France as of September 19;
- THE BA.2.75 sublineage which represents 0.7% of the interpretable sequences. Very little widespread in the country, it circulates mainly in India and is now the majority there.
According to Public Health France, the new bivalent vaccines – approved in September by the High Authority for Health – “may improve protection against Omicron infection”.
Sources:
- New XBB variant of Covid-19: contagiousness, resistance to vaccines… should we be worried about this new strain?, The Midi DispatchOctober 8, 2022
- Risk analysis on emerging variants of SARS-CoV-2 carried out jointly by Public Health France and the CNR Respiratory infection virus, Public Health France, October 5, 2022
