The Omicron variant replicates much better than Delta in the bronchi, but not in the lungs – breaking latest news

The whole world struggles with monitoring the growth of Omicron variant cases. The variant of the coronavirus is estimated to have a greater contagion capacity than Delta (or due to its intrinsic value, or its ability to escape immune) which would lead it to be one of the most airborne viruses ever on the planet.

It multiplies best in the bronchi

A significant problem, given that the greater contagiousness causes the threshold of vaccinated people to increase dramatically, which are used to slow the advance of the virus and that, even if it were a variant of lesser severity, having a doubling rate of cases so fast (currently in the UK of about 2 days) Omicron would be able to bring the hospitals beyond the collapse threshold in a short time (given that some hospitalizations as a percentage always to be calculated on the totality of new positive cases).
Ma why so contagious? An interesting answer could come from the new study carried out by scientists at the University of Hong Kong: preliminary data, published online Wednesday, give us an idea of ​​how Omicron behaves within the first respiratory tract. The variant multiplies about 70 times faster within the bronchi than the Delta variant and reaches high levels of concentration in this area quickly: 48 hours after infection. The many mutations of Omicron (32 only in Spike, the entry protein) seem to have favored the process of entry and replication in the upper airways. These findings from the University of Hong Kong have not been peer-reviewed and the experiments took place entirely within cell tissue in a laboratory.

It replicates less in the lungs

There is also some good news coming from research conducted by virologist Michael Chan Chi-wai and his colleagues. The same experiments were done by infecting with Omicron lung tissue: here the variant proved itself about 10 times less efficient than Delta or the original version of the virus. This finding could suggest that Omicron could cause a less severe disease compared to Delta, but cautions are required: other data is needed, especially from the real world. The tissue isolated in the laboratory does not generate immune responses to fight the virus. And in the study, the researchers only tracked infection with the virus for a 48-hour period. Scientists need to test viral loads within people’s airways (with Delta they averaged 1,000 times higher than the original variants).

Need the third dose

Meanwhile, the alarm caused by the high rates of infection balanced by numerous tests (for now in the laboratory) that a third dose also raises the protection against Omicron: the two doses are no longer enough (there are drops in antibody levels of 30-40 times in vaccinated), but the third dose is well protective towards infections (about over 70%) and even more so towards hospitalizations and severe cases. The antibody responses to the new variant rise with the booster up to 200 times. So far, the results from laboratories.
The first real-world study comes from South Africa and says two doses of Pfizer have reduced hospitalizations by 70% compared to unvaccinated, reinfections are greater, but even then being vaccinated protects. The observations from South Africa, however, are not immediately applicable in contexts such as Italy or other European countries (we have talked about them WHO, ed): it is necessary to wait for data from a country that is more homogeneous to ours, at least in terms of average age and percentage of vaccinated people, for example Great Britain.