Corona mutations, where to and how do virus experts see them?
Viruses may not have the ability to think, but they can adapt to their surroundings to maintain their survival, and this ability to adapt explains the disturbing emergence of several mutated copies that are more capable of transmitting infection, of the virus that causes the Covid-19 epidemic.
Like all other viruses, SARS-Cove-2 can mutate, because when it reproduces, it produces some errors in its formation.
Most of these mutated copies have no effect, but some may give them additional survivability.
This is the case for the three most transmissible versions of the infection that were recently discovered in the United Kingdom, southern Africa and Brazil, and appeared during the fall and months away between them, while no other mutated version of significance appeared during the first months of the outbreak.
Could this be considered a coincidence?
Scientists and experts believe that part of the issue is random, but coincidence is not the only reason behind these shifts.
Emma Hodcroft, an epidemiologist at the University of Bern, explains that "when we reduce the number of infections, we restrict the range of movement of the virus" and thus the possibilities of problematic transformations in it.
On the other hand, when the virus is transmitted at a high level, "the chances are high that the virus will meet a scenario or a certain individual that can accidentally lead to something we do not want to happen," likening that to a game of "roulette".
Wendy Barclay, a virologist at Imperial College London, explains that the conditions of the mutation are a combination of the amount of the virus that moves on the one hand, and the number of times we throw the dice on the other hand, as well as the environment of the virus. ”What is meant is a world in which the virus spreads. Significantly.
She added in a press conference: "This is the moment when we should expect the emergence of mutated copies affected by the immune response, because the level of immunity against the virus in the world is rising through infections and vaccinations."
She pointed out that "in two places where the disturbing mutations appeared, namely in South Africa and Brazil, there was already a high level of immune response in people who had previously been infected with the virus and recovered from it."
However, some scientists question a relationship between the high seroprevalence and the emergence of new copies of the virus.
Bjorn Meyer, a virologist at the Pasteur Institute in Paris, considers that "it is more likely that the transformation takes place within the patient," especially a patient suffering from immunodeficiency, as a number of researchers in the British mutant believe.
"When a patient is immunocompromised, the virus can stay in his body for a longer time," Meyer explains to AFP.
While the virus that causes "Covid-19" lives an average of 10 days in an individual's body, studies have shown that some patients carried the virus alive for weeks, or even several months after infection.
Even in immunocompromised patients, the body also continues to fight the virus without being able to completely expel it.
Faced with this "immune stress", "the virus is forced to mutate."
Either he transforms and teaches himself how to escape from this partial immune response, or he dies, ”according to Meyer.
And why then did a more contagious mutated version appear earlier during the first months of the epidemic?
And expert Meyer points out, "Here chance plays its game ... Not many people have an immune deficiency."
With the onset of the epidemic, the number of infections was lower, and people who knew they were immunocompromised were protected and isolated.
It may differ in regions where there are a large number of people with immunodeficiency or who are not aware that they suffer from it.
The Academy of Medicine in France explains that “the emergence of a SARS-Cove-2 mutant in August in South Africa, one of the countries where HIV infection is most common in the world, may have produced a more intense and prolonged viral replication in the bodies of individuals living with a virus. "Human immunodeficiency, which promoted the accumulation of mutations."
Meyer considers this hypothesis "valid," although it is difficult to pinpoint the exact source of the mutation.
In any case, and whatever the circumstances that allowed for the emergence of a new mutation, the process of natural selection plays its role.
The Belgian infectious disease expert, Yves Van Leitem, summarized the matter in a press conference, saying: “What happens is a natural competition in which the win is for the best, for the strongest, for those who can transmit better, and who are most able to perpetuate the viral type.
It is a typical Darwinian process that directs the evolution of the living world. ”
Proceeding from this, scientists speculate that other dangerous mutations are likely to emerge, unless they have appeared.
“Because the total number of infections continues to rise steadily, it is not difficult to say that problematic mutations appeared during the winter without being able to detect them, more than those that appeared in the fall and are now under,” University of Washington biology professor Karl Bergstrom said in a tweet. We looked », calling for improved monitoring and monitoring.
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