A new variant of SARS-CoV-2, which was first identified by scientists in South Africa on November 24th, has been designated a “variant of concern” (VOC) by the World Health Organization (WHO).
Cases have been discovered in a growing list of countries, including Belgium, Hong Kong, Israel, the UK, Germany and Australia. There is evidence that the new Omicron variant (or B.529) may be more transmissible than the already highly transmissible Delta variant, with reference to the European Center for Disease Prevention and Control.
The “immune escape potential and the potentially increased transfer advantage of the variant compared to Delta”.
Variants of the SARS-CoV-2 virus are not uncommon. The further the virus spreads, the more likely it is that it will mutate.
Mutations occur when the virus reproduces after infecting a human host. Once inside a person, the job of a virus is to educate its human host cells to make copies of the virus that infect other cells and eventually other people.
Because the virus reproduces its genetic material quickly, random errors can occur in your DNA during the copying process. these are called mutations. Most of the mutations are not viable for the virus, which means that they can actually harm the virus; some are viable but not beneficial to the virus;
But now and then mutations can appear that give the new virus, now known as a variant, an advantage over existing variants.
Mutations are much more common in people with compromised immune systems, as they are likely to take longer to clear the virus, which gives them more time to multiply and mutate, and in unvaccinated people, because their immune systems are unprepared for vaccinations to quickly destroy the virus before it can mutate.
South Africa has a relatively low vaccination rate, only about 35 percent of the population is fully vaccinated, and Botswana, where vaccination is suspended, has an even lower vaccination rate – mainly due to global vaccine inequality. If Omicron originated in southern Africa, this may be one of the reasons.
When scientists test new variants before they consider them to be “variants of concern,” they’re trying to see if the new mutations can do three things:
- make the virus resistant to the effects of vaccines;
- make the virus more transmissible than existing variants;
- make people sick if they get the new variant.
It is still too early to know for sure whether Omicron can do some or all of these things, but the fact that the WHO has classified it as a variant of concern means, through an evaluation comparison, that it has been shown to be associated with one or more of the above.
The Omicron variant is characterized by 30 mutations, three small deletions, and a small insertion in the spike protein – the spikes that lie on the outside of the virus and help it enter cells; of these, 15 are in the receptor binding domain, the part of the peaks which allows them to bind to a host receptor.
The most widely used vaccines – Pfizer, Moderna and Oxford AstraZeneca – rely solely on our immune system recognizing the maximum protein part of the SARS-CoV-2 virus as foreign and building an army of immune cells directed against that part of the virus.
But if mutations in Omicron alter the spike protein enough to prevent our immune system from fully recognizing it, it could mean that there is some degree of immune evasion for this variant. It may also mean that those relying on natural immunity, immunity against a previous COVID19 infection – which I don’t recommend – may have reason to be concerned.
There are concerns that Omicron carrier mutations may leave people who have previously been infected at risk for reinfection. According to the WHO, preliminary evidence has suggested an increased risk of reinfection with this variant, compared to other VOCs. However, it is too early to know for sure all of this.
Further virology studies are needed to understand the efficacy of vaccines against the new variant and its effect on re-infections.
WHO said many studies are underway as consultants continue to monitor the Omicron variant may be able to evade existing immunity given by previous vaccines and infections, but the chances of making protection previous unnecessary are extremely weak, and vaccines are much more likely to continue to provide a good level of protection against this variant as well.