Covid-19: the XBB.1.5 variant is “the most transmissible detected to date”, should we be worried?

It’s been a year since Omicron burst onto the scene. Since then, many sub-variants have been identified. The latest, XBB.1.5, dominant in the United States and identified in 29 countries. What are the scientists saying so far?

Four weeks ago, the XBB.1.5 variant caused less than 10% of Covid-19 cases in the United States. Today, it is responsible for more than 25% of cases… and even more than 70% in the northeast of the country.

Although it has been detected in certain nations of the European Union (including France), its presence there remains a minority (less than 2% of cases). Moreover, the latest epidemiological bulletins from Public Health France do not even mention it.

Should we be worried about it?

According to virologists at Johns Hopkins University in Baltimore, “The XBB.1.5 variant has a mutation that helps the virus bind better to cells and therefore be more transmissible.” Element shared by the World Health Organization. In a recent intervention, Dr Maria Van Kerkhove, WHO technical manager for Covid-19, thus indicated that “this sub-variant is the most transmissible that has been detected to date.”

However, for Dr. Van Kerkhove, “there is no indication that the variant would cause a more serious disease”. So far, although it’s still too early to say definitively, “the symptoms of XBB.1.5 appear to be more like the common cold than the flu, especially in people who have been vaccinated or who have already had the Covid-19”, explains the Gavi Alliance.

What about contagiousness?

As Johns Hopkins University points out, “We don’t have hard numbers yet, but based on what we know about XBB variants, someone who was infected with a pre-Omicron variant is likely to be reinfected. by XBB.1.5.” And this for two reasons: “the XBB.1.5 variant is more immunoevasive (that is to say, it escapes the immune system more easily, editor’s note) and a person’s immune response naturally decreases over time after the ‘infection.”

The vaccine, still effective?

Finally, laboratory studies suggest that bivalent vaccines are still effective in protecting against severe forms of the disease…

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