The Epstein-Barr virus (EBV), also called Human herpesvirus 4 (HHV-4), is a virus of the herpes family (which includes Herpes simplex virus and Cytomegalovirus), and one of the most common viruses in humans. Most people become infected at one point with EBV, which is often harmless. It is named after M.A. Epstein and Y.M. Barr, who, along with B.G. Achong, discovered the virus in 1964.

Epstein Barr symptoms vary depending on disease. Diseases associated with EBV include:

• Stevens Johnson syndrome
• Hepatitis