The lungs, along with the heart, are the two most important organs systems for mammalian life. In combo, they provide O2 for cellular energy and get rid of CO2, the waste product of cellular metabolism.

The lungs, from the point of view of histology, the microscopic study of anatomy, be divided into two components:

Shutterstock — the airway is the central structure
  1. The airways which are lined with epithelial, often mucus-secreting cells
  2. The alveoli, which are airspace for O2/CO2 exchange. They are lined by very thin alveolar cells:

Covid, hitherto fore, has made us sick by attacking the alveolar lining cells which are replete with the ACER2 receptor which Covid attaches to, causing potentially lethal Covid lung disease: The S or Spike protein is the biochemical mechanism through which Covid attaches to the alveoli. The result, sadly, is often lethal lung disease where the alveoli necessary for life, fill up with fluid — so O2/CO2 exchange is difficult and all too often lethal:

The above is a photo (from Diagnostic Histopathology) of a lethal case of Covid. The alveolar spaces are full of inflammatory fluid blocking O2/CO2 exchange.

So why is Covid-omicron good news — after all it is way more infectious, a poor respecter of prior immune status and replacing delta. The secret, wonderful readers, is in the mutations of the S Spike of the virus

Forbes, in German and English no less

It is the spike that gives Covid its ability to infect. In all the previous Covid variants, the spike leads to infection of the ACE2 receptor on the alveolar cells, leading often to death or severe morbidity.

The secret (not really a secret) to Omicron’s relative mildness of infection lies in one simple fact — it is much better at infecting the cells of the glandular airway than the flat alveolar cells. Infection of the airways at worst gives us bronchitis. Infection of the alveolar cells can give us death. Quite a difference. As in real estate, it is just location, location, location.

So breathe easier. I am very wary of Omicron because of its high rate of infection. I have masked up. So the good news is not an excuse to forget our Omicron hygiene.

I wish you all a Happy Year of the Tiger,

Peter H. Dohan, MD Portland, Maine




Ex-surgical pathologist, now a photographer; partnered with a unique Chinese surgeon. Well travelled and full of simple love.

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peter dohan

peter dohan

Ex-surgical pathologist, now a photographer; partnered with a unique Chinese surgeon. Well travelled and full of simple love.

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