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Just the word pneumonia is enough to incite fear in the hearts of even the most healthy adults. An infection of the lungs that leads to inflammation of the air sacs, it is caused by microbes and can be fairly lethal if it’s not treated in time.
Turns out, as damaging as typical pneumonia can be—covid-19 caused pneumonia is much worse. Researchers from Northwestern University claim that covid-19 pneumonia spreads like multiple wildfires, leaving destroyed lung tissue in its wake.
According to the researchers, covid pneumonia is significantly different from pneumonia caused by other causes.
Bacteria or viruses like influenza that cause pneumonia can spread across large regions of the lung over the course of hours. In the modern intensive care unit, these bacteria or viruses are usually controlled either by antibiotics or by the body’s immune system within the first few days of the illness.
The findings of the researchers, which was published in the journal Nature, show covid-19 pneumonia is different. Instead of rapidly infecting large regions of the lung, the virus causing covid-19 sets up shop in multiple small areas of the lung. It then hijacks the lungs’ own immune cells and uses them to spread across the lung over a period of many days or even weeks, like multiple wildfires spreading across a forest.
As the infection slowly moves across the lung, it leaves damage in its wake and continuously fuels the fever, low blood pressure and damage to the kidneys, brain, heart and other organs in patients with covid-19.
The severe complications of covid-19 compared with other pneumonias might be related to the long course of the disease rather than a more severe disease, the study authors said.
This is the first study in which scientists analyzed immune cells from the lungs of covid-19 pneumonia patients in a systematic manner and compared them to cells from patients with pneumonia from other viruses or bacteria.
As a result of the detailed analysis, researchers identified critical targets to treat severe SARS-CoV-2 pneumonia and lessen its damage. The targets are the immune cells: macrophages and T cells. The study suggests macrophages cells typically charged with protecting the lung can be infected by SARS-CoV-2 and can contribute to spreading the infection through the lung.
Northwestern Medicine will test an experimental drug to treat these targets in covid-19 pneumonia patients in a clinical trial early in 2021. The drug to be tested quiets the inflammatory response of these immune cells, thus enabling initiation of the repair process in the injured lung.
“Our goal is to make covid-19 mild instead of severe, making it comparable to a bad cold,” said study co-senior author Dr Scott Budinger, chief of pulmonary and critical care medicine at Northwestern University Feinberg School of Medicine and Northwestern Medicine.
Covid-19, like influenza, is unlikely to ever go away, even if much of the population is vaccinated, said senior co-author Dr Ben Singer, assistant professor of pulmonary and critical care medicine at Feinberg and a Northwestern Medicine physician.
“Already, researchers at Northwestern and elsewhere are anticipating mechanisms by which this RNA virus, which mutates quickly, will evade current vaccines,” Singer said.