Patients with severe Covid-19 show increased levels of a key protein in their blood, which researchers believe may help identify those most at risk.
In an analysis of more than 500 coronavirus patients across the UK, scientists identified several inflammatory markers in blood that increased within the early stages of Covid-19 in those who went on to become critically ill.
One marker in particular, a cytokine called GM-CSF, was found at higher levels in those who later progressed to severe disease, compared to healthy controls or those with flu.
It was found to be almost 10 times higher in those who died from Covid-19.