Infectious mononucleosis is an acute lymphoproliferative disease common in children and young adults caused by Epstein Barr Virus (EBV) which is one of the Herpes viruses 4. VCA IgM antibodies occur at the beginning of the disease, but decrease or disappear within a few months. VCA IgG antibodies reach highest titres within 2-4 weeks and persist for many years, maybe lifelong in some individuals.