Omicron Spreads 70 Times Faster Than Delta In Human Bronchus, New Study Says

The Omicron variant infects and multiplies faster than the Delta variant and the original SARS-CoV-2 virus in the human bronchus. Omicron infection in lungs is significantly lower than the wild strain

Representational image comparing different variants of the SARS-CoV-2 Virus (Photo: Getty)

New Delhi: The Omicron variant of SARS-CoV-2 infects and multiplies faster than the Delta variant and the wild strain in human bronchus, a new study has found. The study, led by researchers from the LKS Faculty of Medicine at the University of Hong Kong (HKUMed), is yet to be peer reviewed.

This is the first study to provide information on how the Omicron variant, designated as a Variant of Concern (VOC) by the World Health Organization (WHO), infects the human respiratory tract, according to a statement by the University of Hong Kong.

The fact that the Omicron variant infects and multiplies faster than the Delta variant and the original SARS-CoV-2 virus in the human bronchus may explain why Omicron has the potential for faster transmission in humans, compared to previous strains. The researchers also found that Omicron infection in lungs is significantly lower than the wild strain, which may be an indicator of lower disease severity.

Since 2007, the researchers have been using ex vivo (outside of the living body) cultures of the respiratory tract to investigate emerging virus infections Ex vivo cultures are part of a medical procedure in which an organ, cell, or tissue is taken from a living body for an experiment, and then returned to the living body. They used the technique to understand why the Omicron variant may differ in transmission and disease severity from other SARS-CoV-2 variants. Using the experimental model, they made comparisons of the infection caused by the wild strain of the Covid-19 virus, and the Delta and Omicron variants, in the human bronchus.

Omicron Replicates 70 Times Faster Than Delta & Wild Strain

The Omicron variant was observed to replicate at a rate around 70 times higher than that of the Delta variant and the original strain, 24 hours after the experiment was commenced. However, in the human lung tissue, the Omicron variant was found to replicate less efficiently than the original SARS-CoV-2 virus. The replication rate of Omicron in the lung tissue was more than 10 times lower compared to the replication rate of the wild strain, and this may suggest lower severity of disease, the statement said.

Quoting Dr Michael Chan Chi-wai, the lead author of the study, the statement said it is important to note that the severity of disease in humans is determined not only by virus replication but also by the host immune response to the infection. He explained that this may lead to dysregulation of the innate immune system, and cause a cytokine storm.

He added that a very infectious virus may cause more severe disease and death by infecting more people, even though the virus itself may be less pathogenic.

Taking into consideration the recent studies showing that the Omicron variant can partially escape immunity from vaccines, the overall threat from Omicron is likely to very significant, he noted.