2023 already has its new variant to take into account. Three years after its appearance, Covid-19 continues to give rise to talk, in particular the end of the “Covid zero” strategy in China, which increases the risk of a strong resumption of the epidemic in a population less exposed to the virus and insufficiently vaccinated. . But it is not only in Asia where the coronavirus is worrying.
The US Centers for Disease Control and Prevention (CDC), which tracks the progression of variants, reported last week that a new subvariant was increasingly circulating in the United States: XBB.1.5.
XBB.1.5 is a descendant of XBB.1, itself a descendant of XBB, which is a recombination of BJ.1 and BA.2.75. In short, it is the result of two sub-variants of Omicron, the majority variant in many countries around the world.
A meteoric rise in the United States
During the last week of 2022 (December 25-31), it was present in more than 40% of the sequencing data of positive tests for Covid-19. By comparison, it was only present in 3.7% of positive tests in the first week of December. Also according to the CDC, XBB.1.5 is the cause of 75% of Covid-19 cases in the northeast of the country.
“We haven’t seen a variant progress this quickly for several months,” said Pavitra Roychoudhury, director of Covid-19 variant sequencing in the virology laboratory at the Washington University School of Medicine.
“This is the first time that a recombinant occupies so much space in a Western country”, highlights the CNRS research director, Samuel Alizon, to our colleagues from Parisian.
A priori no more virulent than the other subvariants
Dr. David Ho, a professor of microbiology and immunology at Columbia University, found with his teams that XBB.1.5 was less likely to be neutralized by antibodies from people who had been infected or vaccinated, CNN reports. “Alarming” levels of immune escape that could compromise the efficacy of anti-Covid vaccines, concludes the professor whose work has been published in the scientific journal Cell.
Added to this ability is the ability to easily bind to the ACE2 receptor present in human cells and that the virus uses as a gateway to the body. “It has a better ability to penetrate cells,” confirmed Pavitra Roychoudhury. However, Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, is reassuring about the virulence of the subvariant.
“It does not appear to cause more serious disease and […] it has so much more immunity in the population that I don’t think it’s going to take off,” the researcher said on CNN.
The CDC, if they suggest that XBB.1.5 “may be more transmissible than the other variants” are not capable of affirming that it would cause more severe forms: “we are closely monitoring this variant to see to what extent our vaccines and treatments work.” Against.”
Still very little present in France
Although the CDC has not reported any numbers on the number of sequencings of the XBB.1.5 subvariant, its dominance over other coronavirus mutations is nonetheless established.
A situation that France does not know. Furthermore, there is no mention of XBB.1.5 in the latest epidemiological bulletins of Public Health France dedicated to Covid-19. According to the Institut Pasteur contacted by our colleagues from Parisianonly about fifteen cases have been reported by sequencing in France.
Source: BFM TV
