WHAT DOES CORONAVIRUS DO TO THE BODY?

This respiratory disease invades the lungs, killing vital cilia cells along the way. Then our immune systems release immune cells into the lungs to fight the disease. In some severe cases coronavirus can cause a cytokine storm, which causes cells to attack the body itself.

COVID-19 is a respiratory disease, meaning for most patients the virus begins and ends in the lungs. The new strain of coronavirus has some similarities to SARS. Research from viral infections such as SARS has shown that it’s not necessarily the virus that kills patients, but rather an overreaction by the immune system.

SARS attacked the lungs in three phases – viral replication, immune hyper-reactivity and pulmonary destruction. Not all SARS patients went through all three phases, and similarly early data shows COVID-19 causes milder symptoms in about 82 per cent of cases.

Like SARS, it’s been hypothesised the novel coronavirus infects and kills cilia cells as it invades the lungs. Cilia cells are responsible for clearing out debris such as mucus and dirt.

Serious illness from COVID-19 depends on how the immune system responds to attack from the virus. With the presence of the virus, there’s a release of immune cells, which flood the lungs in an effort to fight the disease. In the most severe cases of the illness, the initial damage caused by the virus can cause the immune system to go into overdrive. This overreaction of the immune system sees immune cells kill anything they come across, including healthy tissue. Pneumonia can become worse as more debris clogs up the lungs.

If lung damage continues to build, this can lead to respiratory failure. For those who survive, patients can be left with permanent lung damage with holes in the lungs.

The hyperactive immune response can cause damage in other parts of the body, too. The body can become overwhelmed with cells and proteins that destroy other organs. This counterproductive response by the immune system is known as a cytokine storm. In some of the most severe coronavirus cases, this cytokine response has resulted in multi-organ failure.

It’s still unclear exactly why some patients have complications outside the lungs, but it could be linked to underlying conditions such as heart disease or diabetes.

Those at risk of a mismatch between the immune system and respiratory illnesses tend to be the elderly and those with underlying chronic illnesses.

“IF LUNG DAMAGE CONTINUES, THIS CAN LEAD TO RESPIRATORY FAILURE.”