Post by Admin on Dec 17, 2021 4:06:12 GMT
A study led by researchers from the LKS Faculty of Medicine at The University of Hong Kong (HKUMed) provides the first information on how the novel Variant of Concern (VOC) of SARS-CoV-2, the Omicron SARS-CoV-2 infect human respiratory tract. The researchers found that Omicron SARS-CoV-2 infects and multiplies 70 times faster than the Delta variant and original SARS-CoV-2 in human bronchus, which may explain why Omicron may transmit faster between humans than previous variants. Their study also showed that the 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.
Research findings
Dr Michael Chan Chi-wai, Associate Professor of School of Public Health and Principal Investigator, Centre for Immunology and Infection (C2i), Hong Kong Science and Technology Park (HKSTP) and Professor John Nicholls, Professor of Department of Pathology, HKUMed have pioneered the use of ex vivo cultures of the respiratory tract for investigating many emerging virus infections since 2007, such as avian influenza, coronavirus of the Middle East Respiratory Syndrome (MERS). Now this technique has been applied to understand why the Omicron variant may differ in transmission and disease severity from other SARS-CoV-2 variants.
This method uses lung tissue removed for treatment of the lung, which is normally discarded, for investigating virus diseases of the respiratory tract. Dr Chan and his team successfully isolated the Omicron SARS-CoV-2 variant and used this experimental model to compare infection with the original SARS-CoV-2 from 2020, the Delta variant and the recent Omicron variant. They found that the novel Omicron variant replicates faster than the original SARS-CoV-2 virus and Delta variant in the human bronchus. At 24 hours after infection, the 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.
‘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”,’ said Dr Chan. ‘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.’
Researchers from the University of Hong Kong’s LKS Faculty of Medicine found that after 24 hours of infection, the omicron variant multiplied in the human bronchus 70 times faster than the delta variant and original coronavirus strain.
They also discovered that omicron infection in the lungs was “significantly lower” than the initial COVID-19 strain, “which may be an indicator of lower disease severity,” according to a statement from the university.
The strain replicated in human lung tissue at a rate that was more than 10 times lower than the original COVID-19 strain, which suggests that it may cause less-severe illness.
The research, however, is still under peer review for publication. The researchers examined lung tissue removed for treatment that was infected with the omicron variant.
Michael Chan Chi-wai, the lead researcher on the study, noted that virus replication is not the only factor that determines disease transmissibility.
“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,’” Chan said in a statement.
He also said that even if a virus proves to be less pathogenic, its highly infectious nature could cause more severe disease and death, which is why he said the threat from the omicron strain is “likely to be very significant.”
“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,” Chan said.
Research findings
Dr Michael Chan Chi-wai, Associate Professor of School of Public Health and Principal Investigator, Centre for Immunology and Infection (C2i), Hong Kong Science and Technology Park (HKSTP) and Professor John Nicholls, Professor of Department of Pathology, HKUMed have pioneered the use of ex vivo cultures of the respiratory tract for investigating many emerging virus infections since 2007, such as avian influenza, coronavirus of the Middle East Respiratory Syndrome (MERS). Now this technique has been applied to understand why the Omicron variant may differ in transmission and disease severity from other SARS-CoV-2 variants.
This method uses lung tissue removed for treatment of the lung, which is normally discarded, for investigating virus diseases of the respiratory tract. Dr Chan and his team successfully isolated the Omicron SARS-CoV-2 variant and used this experimental model to compare infection with the original SARS-CoV-2 from 2020, the Delta variant and the recent Omicron variant. They found that the novel Omicron variant replicates faster than the original SARS-CoV-2 virus and Delta variant in the human bronchus. At 24 hours after infection, the 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.
‘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”,’ said Dr Chan. ‘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.’
Researchers from the University of Hong Kong’s LKS Faculty of Medicine found that after 24 hours of infection, the omicron variant multiplied in the human bronchus 70 times faster than the delta variant and original coronavirus strain.
They also discovered that omicron infection in the lungs was “significantly lower” than the initial COVID-19 strain, “which may be an indicator of lower disease severity,” according to a statement from the university.
The strain replicated in human lung tissue at a rate that was more than 10 times lower than the original COVID-19 strain, which suggests that it may cause less-severe illness.
The research, however, is still under peer review for publication. The researchers examined lung tissue removed for treatment that was infected with the omicron variant.
Michael Chan Chi-wai, the lead researcher on the study, noted that virus replication is not the only factor that determines disease transmissibility.
“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,’” Chan said in a statement.
He also said that even if a virus proves to be less pathogenic, its highly infectious nature could cause more severe disease and death, which is why he said the threat from the omicron strain is “likely to be very significant.”
“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,” Chan said.