Over 2.8 million people worldwide live with multiple sclerosis (MS), a disease in which the body’s immune system attacks the protective myelin coating around nerves in the brain and spinal cord. People with MS can experience pain, fatigue, memory problems, vision loss, and other debilitating symptoms. MS is relatively rare, but new research has found a causal link between Epstein-Barr Virus, one of the most common human viruses, and MS. In this episode, we talk to Dr. Alberto Ascherio, a Professor of Epidemiology at Harvard School of Public Health, about the 20-year longitudinal databank that reveals Epstein-Barr Virus as a causal factor in MS.