The first sample from the Omicron or B.1.1.529 line was taken on Nov. 9 according to WHO. It was noticed due to a spate of cases in South Africa.
“This new variant, B.1.1.529 seems to be spreading very quickly!” Tulio de Oliveira, Director of South Africa’s Center for Epidemic Response & Innovation, and a genetics researcher at Stellenbosch University, on Twitter.
Also, genetic sequencing showed it carried a host of troubling mutations on the spike protein — the knobby structure on the surface of the virus that it uses to grab onto the cells it infects.
Some of those mutations were already recognized by other variants and were known to make them more dangerous, including one called E484A — a slightly modified version of a mutation called E484K that may make the virus less recognizable to some antibodies — proteins of the immune system that a first-line defense against infection and which form the basis of monoclonal antibody treatments.
It also carries a mutation called N501Y, which gave both Alpha and Gamma their increased transmissibility. Last week, Scott Weaver of the University of Texas Medical Branch and colleagues reported in the journal Nature that this particular mutation made the virus more likely to replicate in the upper respiratory tract — think in the nose and throat — and more likely spreads when people breathe, sneeze and cough.
Like Delta, Omicron also carries a mutation called D614G, which appears to help the virus adhere better to the cells it infects.
“The number of mutations by itself does not mean that the new variant will cause problems, although it is more likely to look different from the immune system,” Dr. Peter English, former chairman of the British Medical Association’s Public Health Medicine, the committee said in a statement.
What worries scientists is the number of mutations that affect the spike protein. That’s because most of the leading vaccines target the spike protein. Vaccines made by Pfizer/BioNTech, Moderna, Johnson & Johnson, AstraZeneca and other companies all use only small pieces or genetic sequences of the virus and not the entire virus, and they all use pieces of the spike protein to elicit immunity. So a change in the spike protein making it less recognizable to proteins and cells of the immune system stimulated by a vaccine would be a problem.
So far there is no evidence that this has happened, but there is no way to know just by looking at the mutations. Researchers will have to wait and see if more breakthrough infections are caused by Omicron than by other variants.
The other fear is that the mutations could help make the virus less susceptible to monoclonal antibody treatments. However, the WHO says these mutations are unlikely to affect other Covid-19 treatments, including antiviral drugs under development and the steroid dexamethasone.
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