In the United Kingdom, Brazil, South Africa, California… The coronavirus has mutated in different places around the world. So far, nothing surprising: mutations are usual events in the history of a virus. Concretely, the variants are different versions of the initial virus, which appear as the virus multiplies and errors creep into its genetic material.
More or less remarkable changes
SARS-CoV-2 had moreover mutated several times in 2020. But these mutations had gone unnoticed because they had not had a significant effect on the transmission of the virus, its severity or on the dynamics of the epidemic of covid.
Other mutations stand out more because they give the virus an advantage over other strains, such as better transmissibility. To date, five notable variants have thus been identified.
The British variant
His name is B.1.1.7 or VOC202012 / 01. The British variant of the coronavirus, identified in December 2020, is now spreading at high speed. In France, according to a Inserm report, it could be dominant by March and to date concerns 1.4% of contaminations.
As of January 20, it is already present in 60 countries and territories, already 10 more than on January 12, according to the World Health Organization (WHO). Its particularity: it is more contagious than the old variant. Its transmission rate would thus be between 50 and 70% higher.
The South African variant
The South African variant, called B.1.351 or 501Y.V2, was also identified in December. Like the British variant, it is more contagious than the old variant and therefore spreads faster than the latter.
As of January 20, the WHO has identified its presence in 23 countries and territories, or 3 more than on January 12, including Canada, China, Australia, France (metropolitan France, Réunion, Guyana and Mayotte), Germany, United Kingdom, Ghana, Botswana, Zambia and even Israel.
Two other variants appeared in Brazil: the P1 and the B.1.1.28. The latter would have emerged in the state of Amazonas and was detected in Japan on January 11, 2021, in four people returning from Brazil.
The transmissibility or the severity of these two variants are not yet known, but the first analyzes suggest that B.1.1.28 could also be more contagious than the old variant.
The Californian variant
According to New York Times, a new variant called CAL.20C would have emerged in the United States, California. As of January 20, it would affect 25% of covid cases treated in this state.
It would also be more contagious than the old variant.
These variants appear to be much more contagious than the old variant, but they are not a priori no more dangerous. However, by spreading more, they increase the pressure on already overburdened health systems.
In December, the European Center for Disease Prevention and Control warned that new variants of the coronavirus could increase mortality. Because even if they are not more virulent, they infect more people.
The British, South African and Brazilian variants all share the same mutation called N501Y. It acts on the S protein (for Spike or spicule), the surface protein of the virus which allows it to attach itself to a host cell and to enter it. It is this mutation which would explain that the variants are more contagious.
The California variant also carries a mutation that affects protein S, called L452R.
The South African and Brazilian variants also share two mutations in common: K417T / N and E484K. The latter is of particular concern to scientists because it could make the virus less sensitive to vaccines. According to initial results, it seems in fact to decrease the recognition of the virus by antibodies. As such, it could help the virus to bypass the immune protection conferred by a previous contamination or by a vaccination. In other words, these variants would pose a risk of ineffective vaccines and reinfection.
The effectiveness of vaccines against the new variants is to date the main unknown which worries scientists. The laboratories have so far assured that the vaccines remain effective at least against the British variant and have promised that they will know “adapt“their vaccines quickly enough if necessary. But that means that we will have to start again the production of these vaccines, their distribution and their mass administration.
Finally, another unknown factor worries the experts: the emergence of new variants, more contagious or even more deadly, which could take the advantage over older variants. For the WHO, we must prepare for it because “the more covid-19 spreads, the more likely it is to evolve “.
Faced with this eventuality, only barrier gestures can break the chains of transmission and prevent new epidemic outbreaks.