Omicron is spreading rapidly in all the countries where it is present, sometimes surpassing the Delta variant installed for many months. Scientists at the Hong Kong School of Medicine studied its behavior in several tissues. Omicron seems to develop particularly quickly in the bronchi.
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There are still many unknowns around the variant Omicron, which appeared in South Africa in early November. Now it is circulating all over the world and is starting to take precedence over the Delta variant in some countries, such as UK. According to the latest modeling made across the Channel, Omicron could contaminate 200,000 to 400,000 people a day by Christmas.
How can Omicron spread so fast? Suspicion turns to her protein S hyper-mutated, but information on its behavior in the human body is still limited. Scientists from Hong Kong Medical School carried out experiments ex vivo on normally destroyed lung tissue. A technique perfected by scientists since 2007 and already used to study other respiratory viruses such as influenzas where the MERS-CoV. These results have yet to be reviewed and published in a peer-reviewed scientific journal and may therefore be subject to change.
Omicron spreads quickly in the bronchi
Samples of bronchi and lungs were infected with the Omicron and Delta variants, and the original strain of SARS-CoV-2. Preliminary results presented by Hong Kong scientists indicate thatOmicron infects and multiplies 70 times faster than other variants in the bronchi. This could explain, in part, why it spreads so quickly between humans.
On the other hand, they observed that Omicron is much less active in infecting the lungs, 10 times less than the original strain. Again, this could be the beginning of an explanation concerning the severity of the symptoms caused by Omicron which seem, a priori, lighter. But the viral load in a specific organ is not the only factor that determines the gravity of infection. It also depends on the immune system of each and the appearance of a storm devastating cytokine. Further studies will be needed to confirm the observations made here.
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