First-Ever Biomarker Reliably Predicts Severe COVID-19 Cases Early On

Researchers have identified the first biomarker that can reliably predict which COVID-19 patients will develop severe symptoms, thereby helping to improve the treatment of severe cases.

Researchers at the University of Zurich (Zurich, Switzerland) have discovered a biomarker - the number of natural killer T cells in the blood that 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.


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. The rapid deterioration in the health of COVID-19 patients is caused by an overreaction of the body’s immune system. Many other pathogens besides SARS-CoV-2 can cause pneumonia – and thus spark an immune response. The immune response triggered by COVID-19 has been studied extensively, but the exact nature of the immune response to SARS-CoV-2 has, to date, been unclear. 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.

To detect the immune cells and cytokines in patient samples, the researchers used high-dimensional cytometry. This technology enables researchers to characterize many surface and intracellular proteins in millions of individual cells and process them using computer algorithms. To characterize the immune response to SARS-CoV-2, the researchers also analyzed blood samples of patients with severe pneumonia driven by a pathogen other than the novel coronavirus. By comparing the immune responses in COVID-19 patients with those of the control group, the researchers were able to determine the unique characteristics of the SARS-CoV-2 immune response. The new biomarker test can help clinicians decide which organizational and treatment measures need to be taken for patients with COVID-19, such as transfer to the ICU, frequency of oxygen measurements, type of therapy and treatment start.

“Predictive biomarkers are very useful for making these decisions. They help clinicians provide patients suffering severe symptoms with the best care possible,” said Stefanie Kreutmair, first author of the study. “Our findings also make it possible to investigate new therapies against COVID-19.”

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