Lots of fears and very few certainties. The new Omicron variant, reported at the end of November by South Africa, mobilizes virologists and researchers from around the world to try to understand how it works and its potential impact on the Covid-19 pandemic. Cases of this variant have been reported in 38 countries around the world, according to the WHO. In Europe, it has been identified in 17 countries, according to the latest figures, released Sunday, December 5, by the European Center for Disease Prevention and Control. (in English). Several countries, including France, have already taken measures to try to limit its spread on their territory.
Origin, contagiousness, dangerousness … Franceinfo takes stock of what we know and especially what we still don’t know about this variant.
What we know
It was first reported from South Africa. The variant has “first reported to WHO in South Africa on November 24”, explains the UN body. The first laboratory-confirmed case in the country was identified in a sample taken on November 9. “He’s probably been touring South Africa (…) for longer than we thought, since early October”, for his part explained Wednesday the President of the Scientific Council, Jean-François Delfraissy, in front of the deputies.
In Europe, cases have been identified in 17 countries. In Europe, it has been identified in 17 different countries, according to the latest figures, released Sunday, December 5, by the European Center for Disease Prevention and Control. (in English). The organization then reported 182 cases, but Denmark announced a few hours later, a “worrying” jump to 183 confirmed cases of the Omicron variant in the country. In France, sixteen cases of infection with the Omicron variant have been confirmed, according to the latest report updated on Saturday by Public Health France.
It has more mutations than the Delta variant. A first “picture” three-dimensional study of this new variant was carried out and published on November 27 by the Bambino Gesù hospital in Rome. It allows to show “that the Omicron variant has many more mutations than the Delta variant “, explained the research team. It comprises in particular about thirty mutations in the “spike” protein, the key to entry of the virus into the body. Some were present in known variants, others were not. “This does not automatically mean that these variations are more dangerous, just that the virus has adapted further to the human species by generating another variant”, specify the researchers.
Prima foto al mondo della variant #Omicron realizzata nell’area di ricerca di Medicina Multimodale del Bambino Gesù. Mostra la struttura della proteina spike della variant Omicron a destra e Delta a sinistra rispetto alla spike original SARS CoV-2 #ANSA https://t.co/PtV3nk137S
– Agenzia ANSA (@Agenzia_Ansa) November 27, 2021
It has been classified as “of concern” by the WHO. This new variant is followed “from close” by the WHO which classified it as “worrying” on November 26, in particular because of its large number of mutations. Four other variants belong to this category: Delta, which represents almost all of the cases sequenced in the world, Alpha, Beta and Gamma. It is also the WHO which named this variant “Omicron”, initially baptized B.1.1.529.
What we do not yet know
Its level of transmission. Even if the Omicron variant has a large number of mutations, it is currently difficult to know whether or not these will give it an advantage in terms of contagiousness. Epidemiological studies are underway to understand whether the increase in the number of people tested positive observed in South Africa is linked to the variant, underlines the WHO on its site *. Preliminary South African data, which has not yet been scientifically reviewed, suggests that Omicron may be twice as contagious as Delta, reports the New York Times* (subscribers article). Asked about these elements, the virologist Bruno Lina believes, however, that it is “impossible to generate robust data so quickly”.
In the columns of Sunday newspaper (subscribers article), the scientist adds that he does not “not enough” to examine the situation in South Africa to determine the transmissibility of Omicron. “We have for only elements what happened in South Africa, but at the bottom of a wave and not in a context of strong presence of the Delta variant as in France”, adds epidemiologist Renaud Piarroux to the Parisien (subscribers article). “An important element will be to observe how it will behave in relation to Delta, especially in Europe where this virus is flaring”, continues Bruno Lina.
Whether or not he’s going to supplant Delta. The ability of the Omicron variant to supplant Delta or not will therefore depend in particular on its contagiousness. For the time being, in the great competition between variants, Delta is almost hegemonic in the world. The variants that have appeared in recent months, such as Mu or Lambda, have failed to snatch the top spot. The European Center for Disease Prevention and Control said on Thursday that Omicron could become majority in Europe “in the next few months”. But these forecasts are based on very preliminary data, which may change.
Its virulence. One of the big unknowns remains the dangerousness of Omicron, its ability to generate or not more severe forms of Covid-19. However, Omicron has been detected too recently to give experts time to clinically determine the severity of the cases. The first cases in South Africa were observed in a young population, therefore less likely to develop severe forms, points out the WHO.
The UN body adds that preliminary data suggests “An increase in hospitalization rates in South Africa, but this could be linked to an increase in the overall number of people infected, rather than a specific infection with Omicron”. To date, no Omicron-related deaths have been reported to the WHO. “Even though it is too early to draw any conclusions”, Anthony Fauci, American adviser on the health crisis, ruled on Sunday that “signals concerning gravity [étaient] a little encouraging “.
The efficacy of vaccines on this variant. Again, it is too early to say whether Omicron will be more resistant to existing vaccines. Initial elements of a response are expected “from the end of next week”, explains Anne-Claude Crémieux to Parisian. “A dozen excellent teams around the world are in the laboratory testing whether serum from people who have been doubly, triply vaccinated or recovered is able to neutralize the new variant”, specialist in infectious diseases at Saint-Louis hospital in Paris. But it will take several more weeks to collect real-life data.
For their part, the Pfizer, Johnson & Johnson and Moderna laboratories ensure that they have started to work on new versions of their vaccines targeting more specifically Omicron.
* These links refer to content in English