It seems like every few weeks we hear about a new COVID version, and it’s hard to know how concerned we should be with them.
Now another new combination variant has emerged, called Omicron XE, which results from mixing two Omicron strains in the same patient and then further infecting others.
So what do we know about this new version, and should we need to worry?
Omicron and its types-
Omicron is a variant of the SARS-CoV-2 virus that was first discovered in Botswana on 11 November 2021 and designated a variant of concern by WHO on 26 November. It has since spread around the world and has become the most prominent type of Covid, replacing Delta.
Omicron has since continued to evolve into several distinct lineages, or genetically related subtypes. It also includes the original Omicron BA.1 (b.1.1.529) and BA.2 and BA.3.
BA.2 is more contagious than BA.1 and has now overtaken BA.1 in terms of infection or it can also be said that it has become the new dominant form of SARS-CoV-2 virus worldwide WHO officially announced this on 22 March 2022.
The difference we observed with Omicron compared to previous variants is explained by the relatively large number of mutations, with 60 mutations not found in the original virus that originated from Wuhan, China.
Among these mutations are 32 genetic changes in the spike protein. The spike protein is the part of the virus that it uses to attach to human cells, as well as the target of immunity against the virus from both vaccines and prior infection.
BA.2 shares many of these mutations as the original Omicron variant, but also has 28 unique genetic mutations of its own. Four of these genetic changes are in the spike protein, which explains why some of its features differ from the original Omicron variant (ba.1), including the fact that it appears to be about 30 to 50% more infectious than ba.1. it happens.
What is recombinant?
Just as we have seen new forms of the virus emerge, followed by the evolution of subvariants or different lineages, the SARS-CoV-2 virus continues to mutate in other ways as well. In recent times we have seen not only spontaneous changes in the genetic code responsible for the changes described above, but also so-called recombinants.
A recombinant is one where related viruses exchange genetic material so that both can form new variants with genetic material from the original virus. It can arise when viruses from two different strains (or variants or subvariants) co-infect the same cell.
The genetic material of the virus can mix to form a new recombinant virus, which has the properties of one or both of them of the original virus. So the properties of the recombinant virus depend on which parts of the genetic material from the original virus make up the new version – just as you might have a nose like your mother’s and eyes like your father’s.
When delta and omicron recombine, the resulting progeny is referred to as a deltachron (though more officially these are referred to as xd and xf). This type of recombinant was first identified in France in mid-February and appears to have the genetic sequence mostly identical to that of delta, but with aspects of the spike protein from Omicron ba.1.
So what is XE and where is it spreading?
XE is a recombination of BA.1 and BA.2. There are many other ba.1 and ba.2 recombinants including XQ in the UK, XG from Denmark, XJ from Finland and XK from Belgium.
XE although still comprises a small proportion of sequenced cases, has shown evidence of community transmission, at least within England, where it was first detected in mid-January. Only over 1,100 cases have been registered.
It has also been identified in India, China and Thailand. Initially the pace of growth of XE did not appear to differ much from that of Ba.2, but recent data from the UK suggests that its growth rate is about 10 to 20% higher than that of Ba.2.