C.1.2, a new variant identified in South Africa under surveillance – LCI

The more the virus circulates, the more likely it is to mutate, alert the scientific community for months. And this is widely proven with the appearance of variants more resistant than each other and more contagious. It sounds like a never-ending story: after the Delta, other mutations worry epidemiologists. Starting with C.1.2, currently classified as a potential variant of interest. Observed in May in South Africa, it has since been found in China, the Democratic Republic of Congo, Mauritius, New Zealand, but also in Europe, such as England, Portugal and Switzerland.

At the time of its discovery in South Africa, the variant was formally descended from the C.1 mutation, itself discovered in January. However, according to the study by the National Institute of Communicable Diseases of South Africa, in the pre-printing stage and not yet peer-reviewed, the variant has “considerably changed” compared to its original mutation. Today, it is further removed from the original SARS Cov-2 strain than any other variant observed so far in the world.

Another major concern found in this variant: its mutation rate, which amounts to 41.8 mutations per year and which is almost twice as fast as that of the other variants. A mutation rate equivalent to this has already been observed over a short period in particularly virulent strains, such as Alpha, Beta or Gamma, explain the authors.

Concretely, the study reported “Steady increases in C12 genomes in South Africa on a monthly basis, from 0.2% of genomes sequenced in May to 1.6% in June and then to 2% in July”. All these elements suggest that the C.1.2 strain would risk escaping the Covid vaccines. Moreover, among the mutations sequenced in this variant, N440K and Y449H have already been associated with a risk of immune escape.

In other words, the variant could be more resistant to vaccination but also to a previous infection caused by the Alpha or Beta variants due to the presence of these two mutations, stress the authors. However, the variant having been observed mainly in a country with little vaccination (9.3% of the South African population has a complete vaccination schedule), it still seems early to draw conclusions on possible vaccine resistance. For this, it would be necessary to closely monitor the diffusion of the C.1.2 mutation within a widely vaccinated population.

At this stage, several major properties of this mutation are still unknown, such as its rate of contagion or its dangerousness. But experts at the World Health Organization (WHO) take the variant seriously enough to look into it. According to epidemiologist Eric Feigl-Ding, the institution has started investigating and monitoring variant C.1.2, not yet classified as of concern.