The Cyprus ‘deltracron’ variant and Omicron’s sister in Denmark. What’s going on

From Cyprus the health authorities report 25 cases of a new Covid variant who have provisionally called “Deltacron”. It would be a sort of mix between some mutations of Omicron and others of Delta (in the country, as in Italy, both lineages are present).

Monitoring

Professor Leondios Kostrikis, professor of biology at the University of Cyprus and director of the Laboratory of Biotechnology and Molecular Virology, argues that cases of “deltacron” are more frequent among patients hospitalized for Covid. The sequences were sent (on 7 January) to the international database Gisaid of the Pasteur Institute in Paris. Nothing is known about the characteristics that the compound could have, whether it will be more contagious, more lethal or, simply, if it will succeed in undermining Omicron, which seems quite unlikely given Omicron’s ability to quickly infect people and therefore to impose itself on all other variants.
It is normal for the virus to change continuously and there are many reports that are sent to the databases that collect the genomes: however, in almost three years of pandemic there are only 5 variants reported as “worrying” by the World Health Organization (WHO) and some of these have disappeared, substantially supplanted by Delta and Omicron. However, the monitoring continues.

Omicron’s “sister”

It turns out to be of greater interest a “sister” variant of Omicron that it may have developed on its own at almost the same time and that researchers are keeping in check. To define it, the researchers created 2 sub-lineages of B.1.1.529: BA.1 ie Omicron and the new “anomalous” lineage called BA.2.
From the Denmark raises the alarm: BA.2 may have become dominant over BA.1. The country is one of the best in the world in terms of number of sequences and local data reported on the international sequencing portal Gisaid shows a massive growth of the “new” lineage. In recent days, numerous BA.2 genomes have also been uploaded from South Africa, Australia and Canada. Currently the largest number of sequences related to the variant in question come 82% from Denmark, 7% from Sweden, 3% from India. Both sub-lineages have nearly all of the Spike mutations initially noted for Omicron, but the BA.2 lineage retains some of Delta. In particular, it is difficult to identify with respect to Omicron because it does not have the deletion of the S gene which allows us to suspect belonging to the Omicron variant directly from the swab. To identify BA.2 it is therefore necessary sequence all samples and as we know this implies a laboratory capacity that not all countries have. This is why the data from Denmark are important. Also in this case it is necessary to wait and continue to monitor: many variants were born and remained confined in some areas without spreading or causing concern.

The variant Ihu

Recently also in the south of France another variant called B.1.640.2 had been identified by the experts of theIhu Méditerranée Infection of Marseille and renamed “IHU”. The mutations it presents would be 46, 37 deletions, more than Omicron then. In any case, in fact, it seems a variant limited to the 12 patients reported: the WHO expert Maria Van Kerkhove recalled that the “mother” of this sub-variant, B.1.640, had already been classified as “Variant under monitoring” (VUM ) from the WHO in November, which would suggest it lacks the ability to supplant the prevailing variants.