The new variants of Omicron pierce vaccines more and more easily. If for more than a year the anti Covid drugs have resisted extraordinarily well to all the new strains of the virus (Alpha, Beta, Gamma, Delta), now the trend has diverged. Since the beginning of 2022, the initial version of Omicron, known as BA.1, has given birth to new sublines – BA.2, BA.2.12.1, BA.4, BA.5 – which have sprung up at an alarming rate. . Previous variants did this too. But it never mattered, because their ramifications “had no functional consequence,” according to Eric Topol, founder of the Scripps Research Translational Institute. “They did not increase transmissibility or pathogenicity.”
Omicron, «another 5 years with the virus»: vaccines and war influence the three scenarios “seen” by experts
New more contagious Omicron variants, the role of vaccines
The new variants of Omicron all have one troubling trait in common: are becoming increasingly effective in evading immunity and making people sick who were previously protected by vaccination or a previous infection. The virus, in other words, is evolving faster. Experts therefore warn that the time has come to double the number of next-generation vaccines. “As difficult as it is to deal with mentally, we have to foresee something worse than Omicron in the coming months,” Topol wrote on May 15. “We absolutely need an aggressive attitude to anticipate the virus – for the first time since the start of the pandemic – instead of giving up.”
Hepatitis children, originally “a previous Omicron infection”. The Lancet study
Because vaccines “pierce”
The almost simultaneous – and almost immediate – appearance of BA.2.12.1, BA.4 and BA.5 has shattered these expectations. All three strains share several mutations with BA.2, but also boast additional alterations in a key amino acid called L452, which could help explain why all three evade immunity so well. As Gretchen Vogel of the journal Science explained in a recent article titled “New versions of Omicron are masters of immune evasion”, “L452 is part of the receptor binding domain, the part of the spike protein that attaches to cells, allowing infection. The domain is also a key target for protective antibodies. ‘
Several countries affected
The disturbing aspect of these L452 mutations is that they did not occur in just one strain and one place. They occurred in at least four different sublines in four different countries, all at the same time: Belgium, France, South Africa and the United States (especially New York). This strongly suggests that the mutations were not random, but rather a Darwinian adaptation aimed at helping the virus evade just what seemed to keep cases low in the first place: the huge amounts of Omicron immunity generated over the winter. «We can be sure that [le varianti future] they will continue to be increasingly able to escape the immune system, ”explained Kristian Andersen, who studies viral evolution at Scripps Research.