Hepatitis C Risk Factors and Transmission

HCV is spread primarily by contact with blood and blood products. Blood transfusions and the use of shared, unsterilized, or poorly sterilized needles and syringes have been the main causes of the spread of HCV in the United States. With the introduction in 1991 of routine blood screening for HCV antibody and improvements in the test in the mid-1992, transfusion-related hepatitis C has virtually disappeared. At present, injection drug use is the most common risk factor for contracting the disease. However, many patients acquire hepatitis C without any known exposure to blood or to drug use.

The major high-risk groups for hepatitis C are:

• People who had blood transfusions before June 1992, when sensitive tests for anti-HCV were introduced for blood screening.

• People who have frequent exposure to blood products. These include patients with hemophilia, solid-organ transplants, chronic renal failure, or cancer requiring chemotherapy.

• Health care workers who suffer needle-stick accidents.

• Injection drug users, including those who used drugs briefly many years ago.

• Infants born to HCV-infected mothers.

Other groups who appear to be at slightly increased risk for hepatitis C:

• People with high-risk sexual behavior, multiple partners, and sexually transmitted diseases.

• People who use cocaine, particularly with intranasal administration, using shared equipment.