Two years ago, France experienced its first confinement following the Covid-19 pandemic. Two more followed and new variants appeared. And today, “ where is the evolution of the SARS-CoV-2 virus »? Samuel Alizon, specialist in the modeling and evolution of infectious diseases at the CNRS, takes stock of the issue.
It begins with an important reminder: Our perception of the epidemic is too easily influenced by its trends in France: the picture becomes very dark when it grows, then everything seems rosy when it decreases. This reaction exists even among researchers, but beware. Internationally, we can clearly see that the situation is not synchronized, with in particular a wave of the Omicron variant which is causing a lot of deaths in Southeast Asia. ».
« Omicron marks a break, to the point that one wonders if we are not experiencing an evolutionary branching, that is to say a transition from one species to two different species.adds the researcher.
He ends with a point on mutations:
« Each time someone is infected, billions of new viral particles are produced and increase, following copying errors, the risks of the emergence of random mutants.
This effect is reinforced when a person is infected by several different lines due to recombination: if two viruses are present in the same cell, exchanges of entire portions of genomes can take place.
Again, mutations and recombinations are very likely to be deleterious to the virus, but some may be problematic for us. And with gigantic population sizes, the improbable can become frequent.. »
To learn more regarding the subject, we can only advise you to read this in-house CNRS interview.
