With fewer and fewer restrictions on movement around the world and as countries try to get back to the pace of life before the COVID-19 pandemic, SARS-CoV-2 and its evolution – and expectations – viral dynamics still surprise with a new variant that triggers alarms.
Detected in late March in the UK, the new variant is already present in other countries in Europe, India and Brazil yesterday announced the first infection attributed to the new mutation.
The World Health Organization (WHO) in its epidemiological update report of 29 March rated it as a result of combining the original variant of Ómicron (BA.1) and the BA.2 sub-lineagealso known as silent Ómicron. And he called it XE.
Questions about how long or how often SARS-CoV-2 might continue to replicate had already been raised with the emergence of the BA.2 sub-variant, which, although it generated mild cases of the disease, its transmission rate caused outbreaks in nearly all. the world.
And although early reports currently describe it as silent, highly contagious and with still unclear symptoms, the truth is that XE would transmit 10% faster than its predecessors and its propagation speed is still being studied.
Viruses, as in any organism, occur random mutations, that is, alterations of the genetic material. Most of these mutations will have no effect, but others can change the characteristics of the virus, even give it advantages. For example, some of the coronavirus mutations have made it easier to enter human cells, making it more contagious.
“So far in human history there have been at least six or seven coronavirus species leaps from animal to human and SARS-CoV-2 is only the latest. In all other cases, what has happened is that after an acute phase the virus has become much milder. “the teacher explained Mario Clerici, Professor of Immunology at the State University of Milan and scientific director of the Don Gnocchi Foundation, on the occasion of the outbreak that BA.2 caused in Europe. And he expanded: “And all these coronaviruses, except MERS, which is another story, have always lived with us and give us symptoms that are very mild, very mild colds. So based on what happened with all the other coronaviruses, it is quite logical to assume, to expect, that the same thing will happen with this one too. “
1. Is it a more contagious variant?
WHO has classified variant XE as “high concern” as it arises from the combination of two highly contagious strains, such as Omicron (BA.1) and silent Omicron (BA.2). The study states that XE is 10% more transmissible than the BA.2 variant, which already had 75% infection power over the original Omicron. However, investigations are still ongoing to determine if this is the most contagious variant. At the moment, it remains in the range of what is already known about the Omicron variant.
Likewise, the body recognized it the study of the spread of COVID has become complicated in recent weeks due to the fact that fewer diagnostic tests are performed. This means that the data are “less significant” and “less solid” and, therefore, more difficult to trace “where the virus is, how it spreads and how it evolves”, research is essential to estimate the possibility of entering a new phase of the pandemic.
2. Does it cause the same symptoms?
The first estimates of the WHO study do not indicate that the new variant has symptoms other than those generated by the already known strains of SARS-CoV-2nor that the images it causes are more serious.
That is why specialists agree that the way the infection manifests itself in the body will continue to be with fever, fatigue, runny nose, sore throat and headache.
However, in its latest report, the agency noted that it “continues to closely monitor and assess the public health risk associated with recombinant variants, along with other SARS-CoV-2s, and will provide updates as more becomes available. evidence “.
3. Do Existing Vaccines Protect?
Experts in virology and genomics they do not believe that recombinant XE is more severe or resistant to vaccines than other types of Omicron. The teacher François Balloux, geneticist at University College London, said the variant is likely to follow a similar path to the “long forgotten” Delta AY.4.2 lineage, which sparked fears in Britain but failed to take off elsewhere. In his social networks, Professor Balloux stated: “The XE is not a disturbing variant.”
The vaccines have provided good protection against serious illness and death due to the previous variants, but experts note that a third dose of the vaccine is known to provide the same level of protection against Omicron.
4. What is the difference between a variant and a sub-variant?
The doctor Angela Rasmussen, a virologist at the University of Saskatchewan, Canada, said that “there is no reason to be nervous”. She observed him XE is one of the many recombinants of Ómicron BA.1 and BA.2. “As such, no matter how successful it is, it will remain a sub-lineage of Omicron.” Delta had over 200 of these sub-lineages before being replaced by Omicron.
He also pointed this out “XE is not a Greek letter designating a new variant of interest. It is just a recombination of Omicron, the fifth identified, after XA, XB, XC and XD“. He advised taking the same precautions for COVID-19 in general.
Meanwhile, the teacher Susan Hopkins, Chief Medical Advisor to UKHSA, said: “Recombinant variants are not an unusual occurrence, especially when there are several variants in circulation and many have been identified in the course of the pandemic to date. As with other types of variants, most die out relatively quickly. This particular recombinant, XE, has shown a variable growth rate and we cannot yet confirm whether it has a real growth advantage. “
5. “Mixed” variants are common
As viruses mutate over time, recombinant variants are likely to be produced.
“It has happened a few times before, and usually happens when two variants are circulating and someone is infected with both at the same time, then the virus recombines with the characteristics of both variants.” Carlos Malvestutto is a physician, an infectious disease specialist at Ohio State University Wexner Medical Center, and confirmed in a recent interview that, so far, there is no indication that variant XE is better for escaping immunity acquired from previous infections or vaccinations.
“We don’t really see in these few cases that have been seen in the UK, China and India that it’s causing serious illness,” he said.
What the experts say
“This is the viral dynamics and the result of its replication capacity, which does it billions of times and helps the virus change its genetic characteristics and find ways to survive in a hostile environment.” So he began to explain Infobae the infectious disease doctor and member of the Vaccine Commission of the Argentine Society of Infectious Diseases (Sadi) Francisco Nacinovich (75,823), the reason for the emergence of the new sub-variant.
He continued: “Sometimes those changes make (the virus) more efficient to keep multiplying, spreading and causing damage, and other times those changes, which are made randomly, only allow for one of those characteristics. Perhaps they make it very efficient to disseminate but with less impact on health, or vice versa ”.
As specified by the infectious doctor Roberto Debbag (MN 60253), “The known data on circulation in some European countries is that it is a variant of recombination, ie when the incidence of infection increases due to increased circulation, it also affects immunocompromised hosts and recombinations occur.”
And after ensuring that “today The degree of contagiousness and the impact it will have is not known, nor is it known if it escapes the immune system “, underlined the specialist that” it is expected that it will probably be very similar to Ómicron “.
When asked if XE could cause a new wave of global infections, Nacinovich assured that “obviously it can produce outbreaks and here it is important to underline how science works ”. “It is exemplary that by overcoming any geographical, political or ideological boundary, science works in a collaborative and supportive way and it is a very positive reality that invites us to think about how important it is to invest in science and education, which allows growth in all aspects and it has implications in all scenarios of human life ”, he reflected.
“We are attentive to this type of scenario which puts us with all the alarms ready to see what happens in the country, and how this variant arrives in Argentina”, Nacinovich argued, while for Debbag, “whether this sub-variant produces an impact will depend on each country because it is known that there are four variables that cause what is called the ping pong effect, or outbreaks of COVID in different parts of the world”.
And in this sense he listed: “the rate of the vaccinated population, the types of vaccines used, the vaccination strategies in childhood and whether the impact of Omicron in recent months has generated immunity in the community.”
On this, Nacinovich concluded: “This new context posed by sub-variant XE is also a stimulus for people to agree to complete vaccination programs, which is very important, especially now that the flu is circulating and symptoms can be confusing.”