At the beginning of January, a Cypriot laboratory claims to have detected a hybrid variant of Delta and Omicron. This Deltacron is making a big noise… but is a false alarm. Since then, several serious suspicions have been reported from England, the United Kingdom, Australia, France too.
Variant recombinations, which can occur in people infected with multiple virus strains simultaneously, are not exceptional for SARS-CoV2. When the strains are close, they have few potential consequences.
An impact difficult to predict
“Before the emergence of Omicron, very few recombination events were reported due to the genetic proximity of the viruses,” notes the latest risk analysis on emerging variants, published Monday by Public Health France. But Delta and Omicron, belonging to very different lineages, circulated intensely between December 2021 and January 2022. “It is difficult to predict what the characteristics of the recombinants will be in relation to the variants from which they are derived, and therefore their impact in the event of circulation in the population. »
Four sequences identified
These phenomena are subject to increased monitoring. In France, samples in which a mutation of each of the two variants is detected by screening are subject to complete sequencing. These are mainly co-infections (59 cases as of February 21), but four sequences corresponding to the same recombinant virus have been identified. About ten suspicious sequences, coming from different regions, might “suggesting that this variant has been circulating at a very low level since mid-January”.