What do we know about the new variants called “XD” and “XE”?

The Covid-19 epidemic is at a standstill: contaminations are stagnant but the number of hospitalizations continues to rise in France. In this context, should we worry about the appearance of new variants?

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The figures prove it: the Covid-19 is far from having disappeared from the daily life of the French. And the new “XD” and “XE” variants are there to remind you of the concern. These correspond to either omicron combinations and Delta, this is the case of the “XD” variants, that is, combinations of two forms ofomicron (BA1 and BA2) for “XE”.

Such recombinant forms can appear when two viruses infect the same cell in the same patient at the same time. At this stage, around 60 cases of “XD” have been detected in France, while “XE” is more likely to be found in Britain. According to Étienne Simon-Lorière, head of the RNA virus evolutionary genomics unit at the Institut Pasteur, there are no worrying signs regarding these two variants: “XE” could be slightly more contagious than the BA2but this remains to be confirmed, as its distribution remains very limited at the moment, and there is no particular severity associated with these two variants.

We also hear about the BA4 and BA5 sub-variants. These are subvariants of the Omicron strain, “sisters” of BA1 and BA2. BA2 is still largely dominant in France today, being implicated in over 99% of contaminations.

>> Covid-19 figures: deaths, hospitalizations, vaccinations… Follow the evolution of the epidemic in France and in the world

But since Monday, the WHO has been following a few dozen cases of BA4 and Bac5 in the world, to accurately verify their dangerousness and their possible ability to escape the immunity provided by vaccination or previous infection. At this stage, these very rare variants detected in South Africa, Botswana, Denmark and Great Britain do not inspire concern. They can infect young and vaccinated people like BA1 and BA2 but the symptoms remain without special severity.

These variants do not pose a particular threat for the coming summer or fall, but their existence shows that the epidemic is far from over and that we are not immune from the spread of a variant that would behave differently from the previous ones. Nobody can write a script in advance. For this reason, epidemiologists recommend continuation, surveillance, sequencing, isolation of positive people and search for treatments. Even if more than 80% of the population is vaccinated.

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