The apparent reduced virulence of omicron could be explained by a lower capacity of this variant to attack cells in the lungs. Several preliminary studies suggest this and need to be confirmed.
The characteristics of the omicron variant responsible for the new wave of Covid-19 in the world remain to be precisely defined, but the scenario of a more transmissible but less virulent virus is growing thicker. Very early on, doctors in South Africa, the country where omicron was first detected, reported a lower hospitalization rate for this variant. Preliminary data, which seem to be confirmed over time that this new version of Sars-Cov-2 spreads around the world.
However, it remains to be understood whether this apparent drop in the hospitalization rate is due to a lower virulence of the variant or to the fact that omicron attacks populations that are partially immune (by vaccination or a previous infection) and therefore less likely to develop severe forms.
Initial research results give depth to the first scenario. “We have a few studies which show that this variant multiplies a lot on the nasal cells rather than in the back of the bronchi, which explains why it could be less virulent”, says Sylvie Briand, director of the epidemic risk management department at the World Health Organization (WHO) to Franceinfo.
Preliminary results
Thus, a study carried out on mice in Liverpool suggests that omicron would infect the lungs less than the previous variants, therefore generating fewer severe forms of Covid-19. This study has not yet been formally published but it is in addition to other work carried out in vitro or on other animal models and which also points to a weaker capacity of omicron to infect lung cells than those sinuses. The American doctor Eric Topol gathered the main results of these studies in a tweet.
Hospitals already under pressure
If it were to be confirmed, this news would undoubtedly be excellent. But it will not necessarily be enough to avoid saturation of the hospital system. Indeed, even if it is less virulent, omicron could cause more hospitalizations because of its greater transmissibility and its ability to infect even vaccinated people.
The deprogramming of operations is linked to make room for patients with Covid-19. In Ile-de-France, the leaders of the AP-HP have warned their teams that, next week, the activity will be limited to only “Treatments for which a vital prognosis is at stake“. According to the very latest models from the Institut Pasteur, the future peak of daily hospitalizations linked to the new variant could, depending on its virulence, peak at a manageable level or, on the contrary, reach a new record.