Representative image.

Scientists have decoded how the deadly COVID19 virus kills people.

COVID19 mostly kills through an overreaction of the immune system, said a research report published on Wednesday.

In a study published in the multi-disciplinary journal Frontiers in Public Health, the researchers of China’s Zunyi Medical University explained how the virus infects the airways, multiplies inside cells, and in severe cases causes the immune defences to overshoot with a ‘cytokine storm’.

According to the researchers, the novel coronavirus binds to the angiotensin-converting enzyme-2 (ACE2) receptor through the coronavirus spike (S) protein to invade alveolar epithelial cells to promote direct toxicity and excessive immune responses.

“The induced systemic inflammation causes a cytokine storm, resulting in lung injury, and patients with severe disease develop respiratory failure and die,” the report said.

The report stated that a COVID19 can also lead to multiple organ dysfunction syndrome (MODS).

Excessive activation of lymphocytes in COVID19 patients promotes immune-mediated damage, which causes a mild disease to increase in severity, and single organ involvement to progress to MODS, the report added.

According to the researchers, elderly individuals with reduced immunity and patients with comorbidities are more susceptible to be infected by coronavirus.

The COVID19 pandemic, which has affected more than 4.4 million people across the world, has already created a global health crisis.

Meanwhile, a new study suggests that the protein soluble urokinase plasminogen activator receptor (suPAR) may help scientists predict who is likely to develop more severe COVID19.

The research, published as a research letter in the journal Critical Care, may help clinicians identify people who are more likely to need intensive care support.