because it might worry more than Omicron 2

There is increasing talk of recombinant variants and their potential contagiousness. The United Kingdom’s Health Safety Agency (UKHSCA) has stirred the waters in recent days, the body that first announced that it was carefully monitoring a new recombinant variant of Omicron 1 and 2 (B.1.1.529) and to have assigned it the identifier XE.

The confirmed existence of this new form of SARS-CoV-2, the pathogen responsible for the COVID-19 pandemic, is quite relevant scientific news also and above all to explain the surge in infections in the UK and trace possible implications of a possible future across the Channel.

With 637 cases already identified on British territory, the room for maneuver for the spread of the coronavirus therefore remains considerable. The rate of contagiousness of this form of the virus is therefore being studied. Estimates would see XE as potentially more infectious of the lineage from which it comes, but there is still a long way to go before giving this data for sure.

So let’s take a step back, let’s understand what is meant by recombinant variant and why this is hardly a surprise to scientists.

XE, daughter of Omicron 1 and Omicron 2

The subvariant XE is a recombinant variant daughter of the two main strains from the Omicron: BA.1, the “original” Omicron, and BA.2, the so-called “invisible” Omicron 2 spread from Denmark and today considered the main cause of infections in many European countries.

The UKHSCA to clarify the nature of this specific variant reported as the phenomenon “Occurs when an individual is infected with two or more variants at the same time, resulting in the mixing of their genetic material within the patient’s body”. In other words XE originated in a Covid patient affected by both BA.1 and BA.2.

The product of the meeting of these two branches was sequenced in the United Kingdom and the procedures applied in the English laboratories were also verified by the World Health Organization (WHO). According to the health agency, XE was first detected on January 19 and have been reported and confirmed in the country since then. more than 600 sequences related to it.

Just three days after the official identification, the number exceeded the initial quota of two dozen units. Nonetheless, as stated in the documents of the competent organizations on the subject, XE still represents less than 1% of the total number of cases sequenced in the State.

What is meant by recombinant variant

In early 2021, experts from the Covid-19 Genomics UK Consortium (COG-UK) discovered the first eight SARS-CoV-2 hybrids. In that case the sequences were derived from various lineages that we have now come to know: the variants Alpha, Beta, Gamma, Delta and Omicron. At the time, for example, B.1.36.17 was highlighted, a form that soon spread to south-east UK.

It is therefore not the first time that we are facing a recombinant variant of the Coronavirus. But what is theorigin these mutations? We speak of a recombinant variant whenever a cell is simultaneously infected with two different strains of SARS-CoV-2. British scientists from claimed that:

“Generating a recombinant SARS-Cov-2 genome requires that an individual (and the same cell within that individual) be co-infected from two genetically distinct lineages.”

There simultaneity of an infection and the consequent process is therefore a completely natural phenomenon in pathogenic viruses and is informally likened to a “copy error” in viral replication within a cell.

Given the vast diffusion of these events, starting from the end of 2019, the World Health Organization (WHO) carries out an intense classification activity and, specifically, it aims to catalog the variants of interest (VOI) or variants of concern (VOC).

In fact, in the vast majority of cases these mutations are absolutely irrelevant and therefore do not offer any benefit to the virus itself. But in case they make it more aggressive, monitoring is crucial.

Contagiousness: the direction of the investigation

As normally happens with any new lineage that presents characteristics defined as problematic, the attention is maximum and one wonders if XE will be more or less contagious than other forms of SARS-CoV-2.

The current suspicion of the UK Health Security Agency, as highlighted in the bulletin “SARS-CoV-2 variants of concern and variants under investigation in England – Technical briefing 39”is that this variant has a 9.8% higher growth rate compared to that of BA.2 (Omicron 2), but these are still initial estimates that need not necessarily alarm us.

Professor Susan Hopkins, Chief Medical Advisor at the UKHSCA pointed out how “Recombinant variants are not an unusual occurrence, and as with other types of variants, most will die relatively quickly”.

Prof. Hopkins herself has also drawn up a specific clarification statement which reads:

“This particular recombinant, XE, has shown a variable growth rate and we cannot yet confirm whether it has a true growth advantage.”

To ascertain all this, a substantial amount of data is needed and the expert has also repeatedly recalled how little we know about XE. In short, it is not possible to draw conclusions on the effective transmissibility and virulence of the recombinant variant e there is still no definitive answer not even on the keeping of vaccines. At the moment it is a simple virological detection.

In short, the only certain thing is that the UKHSCA will continue to monitor the situation and carry out strict surveillance on the progress of the coronavirus variants.

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