Injection Drug UseIntravenous drug use is responsible for most of the hepatitis C infections in the United States. Sharing needles, syringes or the other equipment to inject drugs places you in extreme risk for developing acute hepatitis C.
Needlestick Injuries in HealthcareNurses and physicians, and other technicians who routinely use needles while providing medical care, are at risk for needlestick injuries. In fact, it's estimated that more than 600,000 needlestick injuries happen each year, with nurses being at most risk. An average of about 2 percent of needlestick injuries where there has been exposure to the virus will result in acute hepatitis C.
Blood TransfusionIn the past, blood transfusion was a common way hepatitis C was spread. People who had hemophilia or thalassemia (or some other disease requiring multiple transfusions) were especially at risk for exposure. However, now it is very rare because donated blood is tested for HCV antibodies and also HCV genetic material. Experts believe that your chances today of getting hepatitis C from a blood transfusion is about one in 2 million.
Mother-Infant TransmissionSince only about 4 percent of infants born to mothers with hepatitis C will be infected with the virus, this type of spread (known as vertical spread) is relatively uncommon. However, the risk nearly doubles if the mother is co-infected with HIV. Also, the chance of spreading HCV at birth is probably more likely if the mother has a higher viral load at the time of delivery.
Household ContactHepatitis C sometimes spreads within a household, but this is rare. This means that living with someone who has hepatitis C will slightly increase your chances of exposure to the virus. Of course, the risk of this type of spread can be reduced by taking certain precautions. For example, since razors and toothbrushes can in theory be a source of hepatitis C exposure, it's a good idea not to share these items -- especially with someone who has hepatitis C.
Sexual ContactHepatitis C can spread through sexual contact but it doesn't happen often. Unlike the hepatitis B virus, which has been found in semen and vaginal fluids, the hepatitis C virus doesn't seem to be in those fluids in significant amounts. The risk of developing hepatitis C from sexual contact might increase if you have multiple sexual partners, have rough sex (having sex in such a way that may have direct contact with blood), have a sexually transmitted disease or are infected with HIV.
Unknown SpreadThere is a relatively small number of people with hepatitis C who don't know how they were infected. This type of spread is known as sporadic, idiopathic, or community-acquired infection. Some estimates indicate that 10 percent of acute hepatitis and 30 percent of chronic hepatitis result from unknown exposures. Most experts believe that this type of spread is from unrealized exposure to HCV after medical procedures, contact with wounds or some other forgotten higher-risk contact with someone infected with hepatitis C.
Centers for Disease Control and Prevention. Hepatitis C Transmission / Exposure. Accessed September 25, 2009.
Chopra S. Epidemiology and Transmission of Hepatitis C Virus Infection. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2009.
National Digestive Diseases Information Clearinghouse. Chronic Hepatitis C: Current Disease Management. Accessed September 25, 2009.