How is hepatitis C virus spread and how can transmission be prevented?

HCV is spread (transmitted) most efficiently through inadvertent exposure to infected blood.

• The most common route of transmission is needles shared among users of illicit drugs.
  
• Accidental needle-sticks in healthcare workers also have transmitted the virus.
  
• The average risk of getting HCV from a stick with a contaminated needle is 1.8% (range 0% to 10%).
  
• Prior to 1992, some people acquired the infection from transfusions of blood or blood products. Since 1992, all blood products are screened for HCV, and cases of HCV due to blood transfusion now are extremely rare.
  
• HCV also can be passed from mother to unborn child. Approximately 4 of every 100 infants born to HCV-infected mothers become infected with the virus.
  
• A small number of cases are transmitted through sexual intercourse. The risk of transmission of HCV from an infected individual to a non-infected spouse or partner without the use of condoms over a lifetime has been estimated to be 1% to 4%
  
• Finally, there have been some outbreaks of HCV when instruments or sharp tool have been re-used without appropriate cleaning between patients.

Transmission of HCV can be prevented in several ways.

• Programs have been aimed at avoiding needle sharing among drug addicts. Needle exchange programs and educational interventions have reduced high-risk behaviors. However, the population of drug addicts is a difficult population to reach, and rates of HCV remain high among addicts (30% of younger users).
  
• Among healthcare workers, safe needle-usage techniques have been developed to reduce accidental needle-sticks. Newer syringes have self-capping needle systems that avoid the need to manually replace a cap after drawing blood and reduce the risk of needle-sticks.
  
• There is no clear way to prevent transmission of the HCV from mother to child.
  
• Persons with multiple sexual partners should use barrier precautions such as condoms to limit the risk of HCV as well as other sexually-transmitted diseases.
  
• Monogamous couples should consider the low risk of transmission when deciding whether to use condoms during intercourse. Some couples may decide to use them and some may not.
  
• Screening tests for blood products have almost eliminated the risk of transmission through transfusion, estimated by the CDC to be less than one in two million transfused blood products.
  
• People with HCV should not share razors or toothbrushes with others.
  
• It is critical that physicians and clinics follow manufacturer's directions for sterilizing/cleaning instruments and that disposable sharp instruments be discarded properly.

It is important to realize that HCV is not spread by casual contact. Thus, shaking hands, kissing, and hugging are not behaviors that increase the risk of transmission. There is no need to use special isolation procedures when dealing with infected patients.