The new variant of Covid-19, ‘Ómicron’, has the world in anticipation of full Christmas and end-of-the-year celebrations. Know what science says.
The identification of a new variant of SARS-CoV-2 in South Africa, characterized by a large number of mutations (55 in the entire genome, 32 in protein S or spicule) and the vertiginous increase in its relative incidence in that population has skyrocketed once again the alerts on a global scale. Several countries have closed air traffic with South Africa and some experts indicate that it is ” the most worrying variant that we have seen to date “. The WHO has elevated it to the category of “worrying variant” and has designated it with the Greek letter “omicron”.
But, with the available data, can we accept the relevance of these statements? Are they based on demonstrations or are they conjecture? When can we define a new variant as of concern and what consequences does this have on our strategy in the face of the pandemic? I will try in the following paragraphs to shed some light on these issues.
This accumulation of mutations with known effects is already a matter of interest and concern, but adequate experiments have yet to be performed to demonstrate their effects when they are found simultaneously.
The effects of two mutations are not always additive and the interactions (epistasis in technical language) can be both positive (increasing the effect of each one) and negative (decreasing it).
The reason given by the WHO for declaring it as VOC is that it may be associated with an increased risk of infection, although there is still no public information to support this claim.
South African genomic surveillance
However, the red flags have been triggered due to the rapid increase in cases detected in South Africa with this variant. It is not surprising that a new variant is detected in this country, one of the countries with the best SARS-CoV-2 genomic surveillance system and in which, as in almost all countries on the African continent, vaccination has not progressed in the same way.
Thanks to their surveillance, the sequence of the virus responsible for a Covid-19 outbreak observed in Gauteng province was quickly obtained, at a time with a very low cumulative incidence of the infection (around 10 cases per 100,000 inhabitants). In these circumstances, any variant associated with an outbreak quickly reaches a high relative frequency, which may indicate greater transmissibility but also that it grows where there was hardly any.
If the main cause for alarm is transmissibility, other properties associated with mutations in the spicule do not leave much room for reassurance, as we have previously indicated. Again we ask ourselves the question of how a virus with so many mutations arises. The answer is not definitive, but the main suspicion is that it has evolved in a patient with a weakened immune system infected over a prolonged time, after which it has been transmitted to other people in a chain that is unknown to us for now.
What can we do in the face of a new worrying variant?
At the moment, we have the same tools as against the others: vaccinate, wear masks, maintain distances, ventilate closed rooms, that is, reduce exposure and circulation of the virus to the maximum, increase the immunized population in all countries on the planet, limiting the opportunities for new mutations to appear in the virus.
Although we thought that after the delta variant it would be difficult for variants of concern to appear, the omicron variant has surprised us again. Regardless of whether or not it has the serious consequences that justify its declaration as a VOC, it is clear that the evolution of SARS-CoV-2 may continue to bring surprises. The sooner we reduce those possibilities, the better for everyone.