Assessment of the further spread and potential impact of the SARS-Cov-2 Omicron variant of concern in the EU/ EEA, 19th update
In light of the recent emergence of the Omicron SARS-CoV-2 variant, this month's behind the headlines will focus on the impacts this variant has on all of the current progress we have made in dealing with the pandemic. Beyond epidemiological measures, by far the largest global success that we have seen is the development of a vaccine. Various vaccines work in different ways. For example, the Oxford vaccine uses a Chimpanzee adenovirus as a vector to carry the CoV-2 spike protein, whereas the Pfizer vaccine uses mRNA that encodes for the spike protein (it induces your own bodies ribosomes to make the spike protein!)
The spike protein, in particular, is significant as it is located on the extracellular surface of the virus, meaning that it is what our immune system comes into contact with first and is therefore what it uses to detect the virus. As you may have learnt, DNA transcription and translation in humans occurs via the help of various enzymes like DNA polymerases, which are subject to various mechanisms that proofread the sequences and make sure that no mistakes or errors occur. The mistakes that get through this system are termed ‘mutations’ and are often silent, but, at times, can also prove fatal to the cell. When viruses replicate and transcribe their genetic information, a large proportion of the enzymes they use lack this proof-reading machinery, meaning that they are more prone to mutations. This is a good thing for viruses because the more they can vary, the more they can evade our immune response!
Now that you have the background, you may be wondering how this is all relevant to COVID-19. Well, despite how ill-prepared the world was for such a viral outbreak, we can almost consider ourselves lucky that the outbreak was as a result of an adenovirus. This is because these viruses do have their own proof-reading mechanisms to make sure that they don't encode for the wrong proteins and kill themselves! As such, this should theoretically mean that the virus is less prone to mutations and therefore fewer variants arise. This, therefore, means that the spike protein is less likely to change, and thus vaccines should prove to be effective over a longer period (compare this to the flu, for which there is a new jab annually!) Of course, this is only theoretical and, as we have seen, there have been a large number of mutations in SARS-CoV-2 which have varied in transmissibility and severity of the disease. The above articles explain this in terms of the latest variant, Omicron, and show how the spike protein still remains mostly unchanged, meaning that the vaccine is able to elicit both cellular (T-cell) and humoral (antibody) immunity in recipients
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