Covid-19: robot portrait of the Omicron variant, one month after its appearance

It sows discord during this holiday season and gives the impression of an endless epidemic.

With its exceptional contagiousness, Omicron is causing the return of many health restrictions around the world and once again casting a shadow over the recovery of the global economy.

One month after its discovery, France 24 paints a composite portrait of this public enemy number 1 in the light of the latest scientific studies and feedback from the countries hardest hit by this fifth wave of Covid-19.

• A variant "as contagious as measles"

This is arguably the most striking feature of Omicron.

As early as mid-December, the World Health Organization (WHO) had warned of the astounding contagiousness of Omicron, which is spreading "at a rate that we have never seen with any other variant".

In an interview with CNN on December 19, Dr. Jonathan Reiner, professor of medicine at George Washington University in the United States, assures us that “Omicron is the most contagious virus ever known (...). is perhaps the most contagious virus our civilization has faced ".

According to him, Omicron is "as contagious as measles".

In countries around the world, even those with the broadest vaccine coverage, the number of infections is skyrocketing.

In the United Kingdom, 106,000 cases were identified in 24 hours Wednesday, a record since the start of the epidemic.

In France, "we will very likely exceed 100,000 contaminations per day by the end of the month," explained the Minister of Health, Olivier Véran.

The country could even know "hundreds of thousands" of cases of infection per day in January, warned Thursday Arnaud Fontanet, member of the scientific council, during a videoconference.

More broadly, Omicron could be dominant in Europe by mid-January, according to European Commission President Ursula von der Leyen.

However, the news from South Africa, the first country in which this variant was detected, seems encouraging.

In Gauteng province, the epicenter of the pandemic, where Johannesburg and the capital Pretoria are located, there were only 3,300 cases on December 21 against 16,000 ten days earlier.

If caution remains in order, the hypothesis of a fifth wave shorter than the previous ones arouses a glimmer of hope within the scientific community.

• Omicron a priori less dangerous than Delta

Several studies published in recent weeks seem to join the observations of South African hospitals: the Omicron variant would be less likely to cause severe forms of the disease. 

For example, in England, Imperial College London compared cases of Omicron with cases of Delta detected between December 1 and December 14. Result: Individuals positive for the Omicron variant have a 40-45% reduced risk of being hospitalized resulting in a stay of one night or more compared to those infected with the Delta variant.

The South African National Institute of Communicable Diseases (NICD) also suggested Wednesday that Omicron is less dangerous, in the order of 80% for those infected. Spectacular results to be put into perspective according to scientists because the South African population is much younger than in Europe or the United States. In addition, 60 to 70% of South Africans have already been infected once with the virus, probably leading to a better immune response.

Another downside: even if the risk of developing a severe form seems less important with Omicron, hospitals are not immune to an influx of patients in the coming weeks.

The number of contaminations is indeed so high that mechanically the number of hospitalizations could in turn be exponential during this winter period. 

• A variant more resistant to vaccines

According to the available data, two-dose vaccination schedules are not sufficient to significantly reduce the risk of hospitalization after infection with Omicron.

According to virologists, the many mutations that affect the structure of its "spike" protein, the key that allows SARS-CoV-2 to enter our cells.

Several results presented in recent days show Omicron's extraordinary ability to bypass our immune defenses, even when vaccinated.

According to the British National Health Safety Agency, a two-dose regimen of AstraZeneca of more than 15 weeks would be ineffective.

Another study published on December 16 by the Institut Pasteur confirms this drop in the resistance of monoclonal antibodies, even in people who have been vaccinated twice.

On the other hand, this shows that the virus is neutralized up to 75% by the booster dose of a messenger RNA vaccine.

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After Pfizer / BioNTech and Moderna, AstraZeneca assured Thursday that a vaccine booster significantly increased protection against the virus.

The first laboratory results for the Novavax vaccine seem to point in the same direction.

However, data is lacking to know how long this protection lasts.

In contrast, Janssen has yet to release its data, but ongoing studies tend to show that the vast majority of people who have received this single-dose vaccine do not develop neutralizing antibodies against Omicron.

But faced with inequalities in access to vaccination in the world, the boss of the WHO warned on Wednesday against the illusion that it would be enough to administer booster doses to get out of the Covid-19 pandemic .

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