After Omicron, Delta recombinants were detected in France in mid-February, two more Omicron-related recombinant strains have been tracked. Of the three known strains, two are combinations of Omicron and Delta (different versions), while the third emerged from the mixing of 2 different Omicron subvariants (BA.1 and BA.2). A new study pointed out that research is underway to understand what might be the impact of these new COVID hybrid variants.
What are the 3 newly identified recombinant strains?
Explaining the three different recombinant strains, an UK Health Security Agency (UKHSA) study revealed that two different combinations of Delta and BA.1 are XD and XF. The third is XE.
XD is the new name for the French Delta x BA.1 lineage. It contains the Spike protein of BA.1 and the rest of the genome from Delta. It currently comprises several 10s of sequences.
XF is a UK Delta x BA.1 lineage. It has the Spike and structural proteins from BA.1 but the 5′ part of its genome from Delta. It comprises several tens of sequences currently.
XE is a large UK BA.1 x BA.2 lineage. It has the Spike and structural proteins from BA.2 but the 5′ part of its genome from BA.1. It comprises several hundred sequences at present.
How worried you should be about the variants?
Eminent virologist Tom Peacock explained that recombinants that contain the spike and structural proteins from a single virus (like XE or XF) are fairly likely to act similarly to thier parental virus.
XD is maybe a little more concerning. It has been found in Germany, Netherlands and Denmark and it contains the structural proteins from Delta – if any of these recombinants were to act much differently than its parent it might be XD.
All these recombinants (including the smaller clusters that have not been assigned) should clearly be closely monitored for signs of growth and attempts should be made to isolate and characterise where possible, he said in a series of tweets.
COVID-19 could be a recombinant virus
Studies have showed that recombination could be the reason for the emergence of COVID-19 itself. Scientists at the University of Glasgow published a study last month that indicates an animal in the Wuhan seafood market could have been co-infected with two coronaviruses at the same time – and that these two viruses recombined, just like omicron and delta are doing right now, to generate the initial version.