The Epstein-Barr virus infects 90% of adults worldwide. In young children, the initial infection is usually asymptomatic. In adolescents and adults, it usually causes a self-limiting case of infectious mononucleosis. However, the virus remains in certain cells of the body for life. All patients with MS who have been tested have been found to be infected with EBV, and EBV is one of the greater environmental risk factors for developing MS.

References:
Veroni C et al. Front Immunol. 2021;12:665718.