Understanding how COVID-19 attacks the human body is essential to developing an effective treatment or vaccine to stop the global pandemic — but there’s still so much we don’t know about how it can kill us.

As researchers around the world race to understand the illness, they are compiling and sharing their early observations of patients hit by a virus that has sickened more than two million people. The findings are preliminary, but they can help point researchers in the right directions.

They have seen that in severe cases, COVID-19 invades our respiratory cells and triggers an immune system response that targets those infected cells, destroys lung tissue and ultimately clogs our airways, cutting off our oxygen supply.

That’s when organ failure can also occur, causing severe damage to the kidneys, liver and heart, similar to other conditions like sepsis.

But they will look to determine whether the virus is targeting and shutting down organs in a new way or just behaving like other infections that cause such common complications.

Why COVID-19 can be so deadly

One key thing to understand about the deadliness of the coronavirus is how it infects the body and how our body responds to fight it.

Cytokines are small molecules released by the immune system that travel throughout the body to co-ordinate an immune response against an infection or injury — even with something as common as a mild fever.

But if the immune system overproduces them in response to the infection, they can cause “cytokine storms” that can rampage through the bloodstream and severely damage the body.

Dr. Douglas Fraser, an ICU doctor at London Health Sciences Centre and a researcher at Western University in London, Ont., has been studying that exaggerated immune response by collecting blood from critically ill COVID-19 patients in an effort to find new ways to treat the disease.

“The immune response to this particular disease is very different than what we’ve seen in other infected patients that end up in the ICU,” he said. “It’s a unique response and it’s going to require unique therapies.”

Fraser said his research shows there are different types of cytokines released in the body at unusual times and levels in response to COVID-19 compared with those that are typically found in critically ill patients from more common diseases.

“What we’re seeing seems to be occurring in all of the very sick patients: those who are requiring the ICU admissions, those who are requiring assistance with their breathing and those that are ultimately dying,” he said.

Image Credit:  Claudio Furlan/LaPresse via AP