Covid-19: Contagious like Omicron, virulent like Delta… These data on the XD variant that are not reassuring

Bad news on the Covid front with the recombinant variant of Omicron and Delta which would have taken on the worst characteristics of its “parents”.

A study by the Institut Pasteur published on April 4 in prepublication without peer review which evokes the characteristics of the XD variant, this recombinant of Omicron and Delta long called Deltacron.

For the institute, “the recent extensive circulation of Delta in the world and its subsequent replacement by viruses of the Omicron lineage have created the conditions for genetic exchanges between viruses presenting both genetic diversity and phenotypic specificities” (together observable traits of an organism). In the study, the French researchers indicate that “the recombinant exhibits immune evasion properties similar to Omicron, while its behavior in mice (…) is more similar “.

Devastating in mice

Scientists at the Institut Pasteur infected mice with several variants including XD. The results are stunning. First observation, the virus circulates as fast as Omicron but it is just as virulent as Delta with very worrying consequences as L’Indépendant already revealed in recent days.

The mice infected with Delta were struck by a loss of weight from the 3rd day after infection, 6 mice out of 7 having died between the 7th and 9th day. None of the 6 mice infected with Omicron suffered such a fate.

With Deltacron, no weight loss was observed the first 5 days after infection. On the other hand, their state of health worsened between days 5 and 8. All (8) died or had to be euthanized on the 9th day.

Not applicable in humans?

In the end, the analysis of these data suggests that the XD variant would be as contagious as Omicron and as virulent as Delta. However, it is possible that these teachings are not applicable to humans, says Science and Future this Thursday.

Discovered three months ago, XD has grown little while at the same time, Omicron had experienced exponential and meteoric growth and had reached the whole world in just a few weeks.

No more cases detected in France

Spotted in the North of France on January 3, the XD variant is indeed progressing slowly for the moment. As of April 13, a total of 84 contaminations with this variant had been listed in five countries (France, Germany, Belgium, the Netherlands and Denmark) including 65 in France. The latest report from Public Health France, published this Thursday, April 14, however, revealed that the variant had not been detected in the country for two weeks.

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