E-Mail Most people who are infected with SARS-CoV-2 develop no or only mild symptoms. However, some patients suffer severe life-threatening cases of COVID-19 and require intensive medical care and a ventilator to help them breathe. Many of these patients eventually succumb to the disease or suffer significant long-term health consequences. To identify and treat these patients at an early stage, a kind of "measuring stick" is needed - predictive biomarkers that can recognize those who are at risk of developing severe COVID-19. First biomarker to predict severity of disease A team led by Professor Burkhard Becher at the Institute of Experimental Immunology at the University of Zurich, working with researchers from Tübingen, Toulouse and Nantes, has now discovered such a biomarker - the number of natural killer T cells in the blood. These cells are a type of white blood cell and part of the early immune response. "The number of natural killer T cells in the blood can be used to predict severe cases of COVID-19 with a high degree of certainty - even on a patient's first day in hospital," says Burkhard Becher.