Researchers explain why Covid-19 pneumonia is more damaging than typical pneumonia

A new study carried out by researchers at Northwestern Medicine showed that pneumonia-related to Covid-19 is different and more damaging than common pneumonia caused by bacteria or viruses like influenza.

The study, published in the journal Nature, revealed that instead of rapidly infecting large regions of the lungs, the virus causing Covid-19 targets multiple small areas of the lungs.

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. 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 researchers explained.

Severe complications

The severe complications of Covid-19 compared with other pneumonia might be related to the long course of the disease rather than a more severe disease, the study authors said.

Through their study, the researchers identified critical targets to treat severe SARS-CoV-2 pneumonia and mitigate the damage. The targets are the immune cells: macrophages and T cells.

The study suggests macrophages - cells typically charged with protecting the lungs - can be infected by SARS-CoV-2 and can contribute to spreading the infection through the lungs.

“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.

Moon shot research

“This effort truly represents a ‘moonshot’ in Covid-19 research,” said study co-senior author Dr. Richard Wunderink, professor of pulmonary and critical care medicine at Feinberg and medical director of Northwestern Medicine’s ICU.

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.

The study also revealed why mortality among patients on a ventilator for Covid-19 was lower than patients on a ventilator due to regular pneumonia, the study reports. An intense conflagration in the lungs (regular pneumonia) has a higher risk of death.

The researchers noted that those with Covid-19 pneumonia are sick for a long time, but the inflammation in their lungs is not as severe as regular pneumonia.

“If patients with Covid-19 are carefully managed and the health care system isn’t overwhelmed, you can get them through it,” Budinger said.

For the study, scientists performed a high-resolution analysis of the lung fluid of 86 Covid-19 patients on a ventilator and compared it with lung fluid from 256 patients on a ventilator who had other types of pneumonia.