Covid-19: the less dangerous Omicron variant according to animal tests

Several American laboratories and also Japanese have participated in a study on rodents and the effects of the coronavirus: they inoculated different variants of the Covid in mice and hamsters, in order to observe the consequences on their organism.

Adam gault

Text by: RFI Follow

2 min

Covid-19 continues to spread around the world.

The symbolic milestone of one million daily cases has been crossed in recent hours, after the emergence of the Omicron variant, which is particularly contagious.

On the other hand, new studies carried out on animals tend to explain why Omicron would be less dangerous than other variants. 


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It is a scientific report published this week and which the American daily

New York Times


It comes from the SARS-Covid program of the National Institute of Allergy and Infectious Diseases in the United States.

Several American and Japanese and European laboratories have taken part in a study on rodents.

They inoculated different variants of the Covid in mice and hamsters, in order to observe the consequences on their organism.

The idea of ​​a disease that manifests itself primarily in the upper respiratory system is emerging.

My last comment for 2021 in The New York Times 👇on severity of #omicron # covid19

- Roland Eils (@CaptainSysBio) January 1, 2022

It appears that with Omicron, the symptoms would be milder than with other variants such as Delta.

Rodents had a lower viral load and lost little weight.

The explanation of the scientists is that the Omicron would affect more the upper respiratory tracts like the nose, the throat and the trachea, and much less the lungs, which would explain less serious forms of the disease and in particular these famous cytokine storms, these sudden and large-scale inflammatory reactions of the body to viral infection.

See also:

 in the United States, increase in the number of Covid-19 cases and an epidemic peak expected for the end of January

An encouraging study but one which remains to be confirmed by others, and it has only been carried out on laboratory animals.

Scientists, however, have not determined, and this was not the purpose of the study in question, why the Omicron variant is so contagious.

So far, the explosion of the pandemic has not translated into an overall increase in the death toll, which has been declining for three weeks worldwide.

Read also: 

Covid-19 in Japan: the government introduces free PCR and antigen tests


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  • Coronavirus

  • Health and medicine