Most healthy people who are infected by HCMV after birth have no symptoms. Some develop a syndrome similar to infectious mononucleosis or glandular fever, with prolonged fever, and a mild hepatitis. A sore throat is common. After infection, the virus remains latent in lymphocytes in the body for the rest of the person's life. Overt disease rarely occurs unless immunity is suppressed either by drugs, infection or old age. Initial HCMV infection, which often is asymptomatic, is followed by a prolonged, inapparent infection during which the virus resides in mononuclear cells without causing detectable damage or clinical illness.