[Article updated December 21 at 10:30]
The Omicron variant, which is currently spreading rapidly around the world, “could be good news,” say some virological experts.
“I’ve been hearing colleagues say that [Omicron] is ‘devastating’. It is not devastating at all,” French doctor and medical columnist Gérald Kierzek told LCI. "It's not becuse there's an explosion of cases that there's an explosion of hospitalisations."
On December 6, Health Minister Olivier Véran said that the variant is “clearly more contagious and clearly not more dangerous” than the Delta variant.
This is because Omicron has so far appeared to cause milder symptoms in infected people, with Professor Tim Spector, chief scientist on the ZOE Covid symptom tracking platform, telling Sky News that it seems to be “a milder condition that looks just like a severe cold.”
He added that people no longer present the “classical triad” of symptoms: a cough, fever and loss or change in sense of smell and taste.
The top symptoms reported by people who have Omicron are now sneezing, headaches, a runny nose and a sore throat.
Of the 1,000 Omicron cases that Prof Spector’s team have studied so far, “nearly everyone has got better after about five days.”
In the UK, more than 80,000 people have been testing positive for Covid each day over the past week, and data from the UK Health and Security Agency suggest that more than half of new positive cases are now omicron.
However, as of yesterday, the UK government's website reports that Covid-related deaths are falling. Hospitalisations are up by 8% in a week, but this was only a fraction of the increase in daily case numbers, which rose by 52% in the past week.
Royaume-Uni intéressant. >40000 cas par jour depuis des semaines (70000 actuellement) et courbe des hospitalisations et décès « flat ». Décorrelation contaminations/hospitalisations continuent, omicron ou pas. pic.twitter.com/dxGZjEagcP— Dr Gérald KIERZEK⚡ ⚕️ (@gkierzek) December 20, 2021
Fabien Lacols, the founder of Covid tracking site Météo-Covid, has attempted to extrapolate the Omicron-related data which is currently available, and has suggested that Omicron would, in a wave with a comparable incidence rate, cause 40% fewer hospitalisations than Delta, 80% fewer intensive care admissions and 92% fewer deaths.
A vague Delta égale en incidence avec temps de décalage hospi— 〽Fabien_L - Météo Covid (@Fabien_L) December 18, 2021
Total hospitalisé: -40%
Total Rea: - 80% dont personne intubé -87%
Deces: -93% pic.twitter.com/nTTkWJTbqN
Virologist Yves Van Laetham told Belgian newspaper La DH that Omicron could be “a nice present from St. Nicholas,” adding that it is possible that a “less virulent variant is replacing Delta, allowing unvaccinated people to gain immunity in a benign way.
Yves Van Laethem à @ladh: #Omicron pourrait être "un très beau cadeau de Saint-Nicolas, dans le sens où un variant moins virulent remplacerait l'autre et permettrait aux non-vaccinés de s'immuniser. Si les malades ont un rhume et 37,7 de fièvre, cela est moins problématique."— michel henrion (@michelhenrion) November 29, 2021
However, although potentially less virulent, Omicron is definitely more transmissible than previous variants, and is thought to spread two to three times faster than Delta, which was in turn more contagious than Alpha, the New York Times reports.
So, even if it produces milder symptoms, the sheer number of people catching it will surely result in increased hospitalisations, which is why this variant is worrying governments and health authorities across the world.
Omicron currently accounts for 6.8% of all French Covid cases, estimates government-approved information service CovidTracker.
However, France sequences potential Omicron cases on a much smaller scale than the UK, and so the real number is likely to be much higher.
How do variants develop?
Variants appear as a virus replicates inside a cell. During this process, errors can occur and new viral particles can be produced.
Mathias Faure, immunologist at the Centre international de recherche en infectiologie in Lyon, told Le Figaro that “if these new particles manage to dodge [the immune system] they will slowly overtake the original strain” in terms of prevalence.
“The virus is not intelligent,” Dr Faure added. “It evolves according to the constraints which are imposed upon it” and not in order to survive. In theory, it is possible for it to become either more or less virulent, he said.
Early in the pandemic it was sometimes suggested that the virus would gradually lose virulence (likelihood of causing severe symptoms), with the theory that as it evolved to survive better, perhaps becoming more transmissible, it would weaken so as to avoid harming its hosts too quickly. However this has not so far proven to be the case prior to Omicron.
One of the authors of a study this summar on the evolution of the virus's virulence in the Journal of Evolutionary Biology, Mircea Sofonea, states that “infections by the Alpha variant [originally called the UK, or 'Kent' variant] resulted in death more often than those caused by previous strains,” and that “the latest available results also show that the Delta variant is more virulent than Alpha, because it caused a greater number of hospitalisations among unvaccinated people.”
Meanwhile many other viruses never became less dangerous through evolution. Often, when a virus mutates to become more transmissible, it also becomes more virulent, as it increases its production of viral particles. This serves both to make it more contagious and to worsen infected people’s symptoms, as the number of particles working on the body is greater.
If Omicron is indeed proven to be milder than Delta – as initial findings suggest – it will buck this trend.