COVID-19 vs Flu: Coronavirus causes much more severe damage to lungs

The novel coronavirus has been found to damage lungs much more severely than the seasonal flu virus, attacking the inner lining of blood vessels, according to new research.

A team of researchers compared the lungs of patients killed by COVID-19 with lungs of people who died from flu. Both viruses belong to the same category and infect the respiratory system, causing multiple blood clots.

But the new coronavirus causes intensive damage to the inner linings of the blood vessels in the lungs, said the findings published in the journal, The New England Journal of Medicine.

As a result of the damage in the capillaries' inner lining, the movement of carbon dioxide transported by the blood from which oxygen is extracted inside the lungs is blocked, causing shortness of breath, a distinctive symptom of COVID-19.

Surprisingly, researchers also found the growth of new blood vessels in the lungs of coronavirus victims.  "Patients with COVID-19 showed widespread blood clotting as well as new vessel growth – the latter likely a result of the body's response to the virus," said the researchers. 

The damaged blood vessels lead to other conditions caused by the virus, including COVID toe, Kawasaki disease in children, stroke, and other conditions like loss of smell.

During the initial days of the outbreak, many linked the new virus to the seasonal flu, which kills 290,000–650,000 every year. As the coronavirus outbreak severity turned into a pandemic, many studies debunked its comparison with the flu. 

Within five months of the outbreak, which was first reported on December 31, the new virus has killed more than 347,944 people as of May 26.

While the lungs of both coronavirus and flu victims shared some common features, there were distinctive features related to blood vessels seen in the lungs of patients who had died of COVID-19, researchers added.

(Cover: A patient suffering from the coronavirus is treated at the Cernusco sul Naviglio hospital in Milan, Italy. /Reuters)