It is still unclear why many people infected with COVID-19 have mild symptoms or none at all while others experience severe cases or even die. In patients with severe COVID-19, the lungs become inflamed, and sometimes the heart or kidneys are also affected. Blood often overcoagulates, which can cause clots to form in the lungs. It is the most common acute cause of death in severe cases of COVID-19. Now, a team from universities and research institutes in northern and western Germany and the neighboring Netherlands has found a key indicator in the blood of COVID-19 patients that could serve as an early warning of a severe case. Source: German scientists identify warning sign for severe COVID | Coronavirus and Covid-19 – latest news about COVID-19 | DW | 01.12.2020