The immune system of people with COVID-19, the illness that the coronavirus SARS-CoV-2 causes, can also go into overdrive, producing excessive quantities of immune signaling molecules called cytokines. Stay informed with live updates on the current COVID-19 outbreak and visit our coronavirus hub for more advice on prevention and treatment.This cytokine release syndrome, or “cytokine storm,” results in hyperinflammation, which exacerbates the person’s breathing difficulties and can lead to potentially fatal acute respiratory distress syndrome (ARDS).