Hello Abay Sisay Misganaw

Omicron VOC produces fewer damaging infections, often limited largely to the upper airway (the nose, throat, and windpipe). This variant causes less harm to the lungs, while previous variants would cause scarring and serious breathing difficulty.

The reason that Omicron is milder may be because of the anatomy. Studies have found that Omicron levels in the lungs were one-tenth or less of the level of other variants. In the lung samples, the researchers found that Omicron grew more slowly than Delta and other variants did.

A molecular explanation for why Omicron doesn’t fare so well in the lungs has been provided by researchers who state that many cells in the lung that carry a protein called trans-membrane protease serine 2 (TMPRSS2) on their surface doesn’t grab on to Omicron very well. As a result, Omicron does a worse job of infecting cells in this manner than Delta does.

Studies have found that through an alternative route, coronaviruses can also slip into cells that don’t make TMPRSS2. Higher in the airway, cells tend not to carry this protein, which might explain the evidence that Omicron is found there more often than the lungs.

Omicron has switched its route of entry into human cells. This is likely to influence Omicron spread and the types of cells it can hijack. You may get more details in the link provided below.

https://www.gla.ac.uk/research/az/cvr/engage/news/headline_829358_en.html

Also, you may want to refer to the articles attached below for more information on this subject.

https://www.nytimes.com/2021/12/31/health/covid-omicron-lung-cells.html

Article Contributions of human ACE2 and TMPRSS2 in determining host–...

Best.