First information on how Omicron SARS-CoV-2 infect human respiratory tract. Omicron infects and multiplies 70 times faster than the Delta in human bronchus, which may explain why Omicron may transmit faster Omicron infection in the lung is significantly lower than the original SARS-CoV-2, which may be an indicator of lower disease severity. This research is currently under peer review for publication. Pioneered the use of ex vivo cultures of the respiratory tract, for investigating many emerging virus infections since 2007
Lung tissue removed for treatment of the lung : Dr. Chan and his team successfully isolated the Omicron SARS-CoV-2,and used this experimental to compare infection with the original and Delta variants 24 hours after infection, Omicron variant replicated around 70 times higher than the Delta variant and the original SARS-CoV-2 virus.
In contrast, the Omicron variant replicated less efficiently (more than 10 times lower) in the human lung tissue than the original SARS-CoV-2 virus, which may suggest lower severity of disease.
Dr Chan: It is important to note that the severity of disease in humans is not determined only by virus replication but also by the host immune response to the infection, which may lead to dysregulation of the innate immune system, i.e. “cytokine storm”,
It is also noted that, by infecting many more people, a very infectious virus may cause more severe disease and death even though the virus itself may be less pathogenic. Therefore, taken together with our recent studies showing that the Omicron variant can partially escape immunity from vaccines and past infection, the overall threat from Omicron variant is likely to be very significant…