Deltacron, a hybrid of Delta and Omicron, is the new coronavirus variant that was discovered in mid-February. There are now over 60 protocols, covering Cyprus, France, the Netherlands, Denmark, the USA and the UK. Will deltacron displace Omicron? Will the variant be better for avoiding immunity? and will it cause a more serious illness?
By Luke O’Neill
In many countries, when restrictions are lifted and freedoms are restored, there is a general feeling that the pandemic is over. However, there is still significant concern that a dangerous new variant could emerge.
This happened when omicron arrived, but we were lucky with it. Omicron has proven to be more transmissible, but at the same time, it has not caused any increase in serious illness in most countries where it is dominant.
But this was not guaranteed. Variants appear randomly, and new ones have the potential to be more dangerous than the previous ones. Another has just arrived, and is currently going by the name deltacron. It’s – as you can probably imagine – a hybrid of Delta and Omicron, the two variants dominating recently.
Deltacron’s story begins in mid-February, when scientists at the Pasteur Institute in Paris uploaded a genetic sequence of the coronavirus, which looked very different from previous sequences.
The virus sample came from an elderly man in the north of France and looked strange. Most of its genetic sequence was the same as Delta’s, which was globally dominant until the end of last year, but that part of the sequence that encodes the spike protein of the virus – a key part of its external structure that it uses for in Cells to come. the body – came from omicron.
By March, three more hybrid genetic sequences had been reported, this time in the United States. There are now over 60 protocols, in France, the Netherlands, Denmark, the USA and the UK.
However, there may be different delta crowns. Scientists at the Pasteur Institute have said that the deltacron sequences reported in the United Kingdom and the United States have different differences from those found in other countries. They said it was necessary to add a number to these different forms of Deltacron to indicate what is what.
Coherence: Coronavirus: New Deltacron variant discovered in Cyprus
How these coronavirus hybrids formed
It is not uncommon for viruses to mix and match parts of themselves when two different viruses infect a cell. This is called “recombination” because a virus combines parts of its genetic sequence with parts of another related virus as it compiles copies of itself. It seems to happen by chance during viral replication.
However, when there is a power transfer from one viral variant to the other – with one variant becoming less common and another more, meaning that both circulate in the population and there is a chance of infecting people at the same time – the chance that the recombination happens is up. . This would have been the situation when Omicron emerged to displace Delta as the most dominant form worldwide.
Recombination usually creates a new virus that is not viable, because mixing different genes can interfere with the virus’ ability to make the proteins it needs to survive. But sometimes one survives, and that seems to be what happened to Deltacron.
In fact, because the Deltacron hybrids found in the US / UK appear to be different from those found in mainland Europe, it is possible that this happened several times separately.
A chip from the old block?
At the moment, it’s hard to say in what way Deltacron’s parents look. Delta and Omicron are very different viruses. They differ in how they infect cells and how they prevent immunity. We still do not know enough about Deltacron to say how different it will be.
Since it has been found in many neighboring countries, it is possible that Deltacron is spreading. However, the Omicron itself continues to spread far and wide in Europe, so it is still the variant that we now need to look closely at.
Time will tell whether Deltacron displaces Omicron, and whether Deltacron is better for avoiding immunity and whether it will cause more serious illness. There are currently too few Deltacron cases to draw conclusions on these issues. What we need are experiments to determine the properties of Deltacron – the scientists started this process and were able to infect cells with it, so hopefully we have answers in time.
In the meantime, we need to keep that in mind. The fact that Deltacron may have spread across borders underscores the need for continuous genomic surveillance to keep track of how the virus is changing and moving. As the coronavirus continues to spread and infects large numbers of people, it is possible that more variants will emerge – also through recombination.
We can, however, be somewhat confident that the previous infection with other variants, as well as vaccination, will offer protection from serious diseases when the deltacron begins to dominate. We know that vaccines based on the original Wuhan strain of the virus also protect against serious illness with the more recent variants. Time will tell if Delta and Omicron produced a wild child to worry us.
Luke O’Neill is Professor of Biochemistry, Trinity College Dublin
The article was published in The Conversation and republished under a Creative Commons license.
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