Most healthy children, adolescents and young adults recover within 1–2 months with no medical intervention and no resulting sequelae. Numerous attempts to associate EBV infection with other disease syndromes have been made, but none have been definitively substantiated. The best studied of these entities is Chronic Fatigue Syndrome, an illness characterized by persisting fatigue, weakness, myalgia and arthralgias, and occasionally lymphadenopathy, pharyngitis and low-grade fevers. Although studies have not supported an association with chronic fatigue syndrome, experts do recognize the entity of chronic active EBV in the rare patient with fever, hepatosplenomegaly, and fatigue persisting for a year or occasionally more after an acute infectious mononucleosis illness. These patients are distinct in that they have demonstrable organ dysfunction directly attributable to EBV by immunohistochemical staining.28 Additionally, they have extremely high serum EBV viral loads by polymerase chain reaction, and markedly elevated anti-VCA and EA antibody titers, but never demonstrate antibody to EBNA.29