How do you get Hepatitis C?

Hepatitis C is caused by a blood borne virus, the Hepatitis C virus. The virus was not discovered until 1990, so blood donors or blood products transfused before that time could not be tested for the presence of the Hepatitis C virus and eliminated from the transfusion pool. Transmission of the disease is from an infected person's blood to the blood of another person. Most cases can be traced to recreational injectable drug usage, intranasal cocaine usage, nonsterile body piercing or tattoos, transfusions prior to 1990, or medical needle stick from an infected source. Often, the exposure to the infected blood occurred 20-30 years before the disease became apparent. About 5% of cases have no obvious risk factors to explain the cause. Body fluids of an infected person other than blood generally are not infective unless they are contaminated by the blood of the infected person. The risk of sexual transmission is low (one study suggested 3% after 40 years of exposure) if the partners are monogamous, exclusively heterosexual, and generally avoiding behaviors which are designed to cause bleeding.