Omicron slow to infect lungs, says Hong Kong study

What is the News?

Researchers from Hong Kong have released a study on why the Omicron coronavirus variant is spreading so fast.

About the study

The researchers used the lung tissue for investigating viral diseases of the respiratory tract. After isolating the Omicron variant, they used it to compare the infection with the original SARS-CoV-2 from 2020, the Delta variant and the Omicron variant. 

What are the key findings of the study?

Omicron multiplies 70 times faster than either the Delta variant or the original SARS-CoV-2 virus within the human bronchi — the two large tubes that carry air from the windpipe to the lungs.

This could explain why Omicron seems to transmit faster between humans than previous variants.

However, the study also found that the Omicron does not easily infect the lower lungs, and this could potentially explain why instances of severe disease are proportionally lower in cases involving Omicron.

Note: It is the lungs, not the bronchi, that are linked to potentially life-threatening COVID-19 complications such as pneumonia and, in severe cases, acute respiratory distress syndrome or ARDS.

But the study also cautioned that the severity of the disease is not determined only by virus replication but also by the host immune response, which may lead to cytokine storm.

Source: This post is based on the article “Omicron slow to infect lungs, says Hong Kong study” published in The Hindu on 17th Dec 2021.