Researchers have carried out analyzes allowing them to identify no less than 12,000 mutations of the SARS-Cov-2 coronavirus! In their conclusions, the scientists estimate that for the moment, none of these mutations was synonymous with a stronger contagiousness of the virus.
Since the start of the Covid-19 epidemic, the SARS-Cov-2 coronavirus has mutated. This therefore raised questions about a potential stronger or weaker virulence depending on the mutations . Concern has also surfaced, particularly in Denmark and France where farms of contaminated whole mink have been sacrificed. The precautionary principle has reduced fears about a potential mutation of the coronavirus in these animals making the vaccines being developed less effective. Later, however, initial data showed that this misadventure had little risk of occurring.
Let it be said, coronavirus mutations are normal although they generally have a low mutation rate. Indeed, all viruses mutate and there is nothing rare or surprising in this. Most of the time, these changes have no consequences. On the other hand, it can sometimes change the genetic material of the virus, thus affecting its transmissibility and virulence.
A publication in the journal Nature on September 8, 2020 gave the floor to Norwegian molecular epidemiologist Emma Hodcroft. She recalled that SARS-CoV-2 accumulates only two mutations per month of a single letter in its genome. According to the expert, this rate of change is about half that of the flu and a quarter that of HIV.
While coronaviruses have a low mutation rate, some of these mutations may still be significant. Let us cite, for example, the D614G mutation, which has been firmly established in Europe for several months. Various studies on the subject were the subject of prepublications, but were not strong enough to allow firm conclusions. Did the mutation in question generate greater virulence? Since the beginning of the epidemic, has there ever been a mutation increasing contagiousness?
In order to answer these questions, researchers from University College London (UK) conducted a study published in Nature on November 20, 2020. Biologists and geneticists analyzed approximately 46,000 genomes of the SARS-CoV-2 coronavirus present worldwide and have identified 12,706 mutations . Modeling made it possible to understand whether one of these mutations increased the transmission of the virus. This phylogenetic analysis aimed to trace the evolution of mutations.
In conclusion, British researchers claimed that the most widespread mutations are neutral. None of them (even D614G) is accompanied by a higher transmission of the virus. However, the scientists felt that their model could in the future quickly identify a potentially dangerous mutation.
