The World Health Organization (WHO) has designated the new virus B.1.1.1.529 of the lineage SARS-Cov-2 with the name Omicron as a causative variant of the virus (VOC). This variant is believed to have originated in southern Africa. The decision has triggered a massive shift in priorities in pandemic management globally. The WHO has recommended, among other things, increased surveillance. In particular, virus genome sequencing, focused research to understand the dangers posed by this variant and measures to prevent it such as mandatory wearing of masks has been called for intensifying.
More restrictions on international travel are already in place in the UK and many other countries. Actually, Japan has closed its borders to all foreign tourists. The rapidity shown in declaring this version of the virus as a VOC is astonishing. A little more than two weeks have passed since the first known infections of the virus in Botswana and South Africa. Compare this with the Delta version which is currently active in Europe and many other parts of the world. The first case of this variant was reported in India in October 2020, but despite the huge jump in cases in the country (as well as in many other countries), it took at least six months to get the VOC status.
Why is WHO nervous about the new variant?
There was certainly a slowdown in recognizing the threat posed by Delta, and no doubt a lesson has been learned about the importance of telling the world about dangerous new forms of the virus as soon as possible, but this delay is a new one. It also reflects the difficulties faced in providing convincing evidence regarding the capabilities of the edition. There are three types of traits that determine the threat posed by a new variant. These are communicability (the rate at which it spreads from person to person), the ability to penetrate the virus (the severity of disease symptoms) and the immune system (the degree of protection a person has from a vaccine or natural infection).
The underlying genetics and evolutionary processes between these three phenotypes are complex, and their detection requires both detailed clinical and epidemiological data and careful experimentation in the laboratory. Now the question arises as to what is in the Omichrome version that has prompted the WHO and many experts around the world to move towards declaring it a VOC with so little data – and whether their warnings are justified. That this version is the ‘most worrying’ of all the editions that have come out so far? There is no evidence to suggest that Omicron causes more severe disease, but there is virtually no data available.
The Omicron version spreads more quickly than other types
It is yet to test the accuracy of the information coming from South Africa that mild symptoms develop when sick with this version of the virus. Yet its transmissibility and its ability to penetrate the immune system are clear cause for concern. The increased transmissibility of a new variant can be difficult to pin down, as its disastrous effects can lead to an alarming increase in case rates without the need for any underlying changes in viral genetics. The general consensus is that the Omicron variant probably spreads more quickly than the other types. In the South African province of Gauteng, the R number (the number of other people infected with the virus on average by one infected person) is believed to have increased from about 1.5 to about 2 since the arrival of Omicron, which if true. There is an important change.
Unsurprisingly, it is also being extended to many countries outside southern Africa, including the UK, Israel, Belgium, Canada, Australia, the Netherlands and Austria. Disturbing fact The most troubling feature of the Omicron variant is that it undergoes a very rapid morphological evolution, which is reflected by the unprecedented number of mutations in its genome. How this happened is a subject of constant speculation but, critically, 32 mutations have affected the spike protein, many of which are known to alter how the virus interacts with antibodies produced by vaccines or prior infection. Is. It is this ability to ward off increased immunity, along with the rapid spread rate, that is causing so much concern. But making predictions about the likely behavior of a virus from the genome sequence alone is not an exact science. And there is no direct correlation between the number of mutations in a variant of the virus and the threats it poses.
Surveillance and global research needed to contain the spread
There is definitely a need for closer monitoring and global research measures to stop the spread of the Omicron variant. So it is too early to say what kind of challenge we are facing. A clearer picture should emerge as the evidence comes in in the coming weeks. In the meantime, the world should be grateful to South African and Botswana scientists and public health officials for their alertness and openness, and to redouble our efforts for equitable and speedy distribution of vaccines around the world in the face of this new version of the virus. This should be seen as a new call to doubling.
Ed Feil, Professor of Microbial Evolution at The Milner Center for Evolution, University of Bath
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