Hepatitis C virus (HCV) transmits primarily through blood and blood products, and the majority of people in the US may have become infected from receiving blood transfusions prior to 1990 (when screening for the virus began) or via intravenous drug use.
Sexual transmission between monogamous, heterosexual partners is rare, but the incidence of HCV infection among men who have sex with men has risen significantly in recent years, and risk of transmission may increase with any practice that involves potential blood-blood contact and high-risk sexual practices.
Independent of its association with HIV infection, HCV is a major cause of liver disease. It is associated with nearly 50 percent of the cirrhosis, end-stage liver disease, and liver cancer cases in the overall population, leading to an estimated 10,000 to 12,000 deaths annually in the United States. HIV/AIDS is responsible for approximately half of all deaths among people living with it. This is a significant increase from an approximately 12 percent mortality rate in the era before highly active anti-retroviral therapy (HAART). In other words, as more people are living longer with HIV, an increasing number are succumbing to HCV-related liver disease.
In the absence of HIV co-infection, HCV disease typically progresses very slowly. It may take decades before symptoms appear, if at all. In HIV co-infected individuals, however, HCV disease develops more rapidly. Some research indicates that HCV may replicate 8 times faster in co-infected individuals, and these individuals commonly progress more rapidly to develop cirrhosis, liver failure, liver cancer, or end-stage liver disease.
There is conflicting data regarding the effect of HCV on the progression of HIV infection. More research is needed to determine whether co-infection with HCV significantly affects the speed of progression from HIV+ status to full-blown AIDS.
Outlook on HIV-Hepatitis C Co-infection
Despite the serious realities of these conditions, there is a very positive outlook on HIV-hepatitis C co-infection:
- Successful treatment and significantly improved outcomes for HCV-infected people living with HIV/AIDS is possible with the latest drug regimens.
- Side effects can be effectively managed to ensure treatment success.
- Liver (and kidney) transplants are possible for people living with HIV/AIDS, and Mount Sinai is investigating their effectiveness as a treatment for HIV-HCV co-infection.
Viral infections, including HIV and HCV generally cause few or no symptoms during the early stages of infection. However, the immune system can produce special proteins called antibodies as a reaction to the presence of a foreign substance-in this case, the virus-long before the onset of symptoms. First-line antibody screening tests look for these proteins as an indicator of infection.
These tests are very sensitive to the early signs of infection, but they are often less accurate than others that detect the virus. For this reason, a second test often follows a positive screening to confirm the virus is present.
- The ELISA test (Enzyme Linked Immunosorbent Assay), looks for HIV antibodies in blood. If antibodies are detected, the test must be confirmed before a person can be considered HIV positive.
- The Western Blot or Immunoflouroscent Assay (IFA) is performed to confirm a positive ELISA result.
- An EIA test (Enzyme Immunoassay) also looks for HCV-specific antibodies in the blood. A reactive (positive) result indicates likely exposure to hepatitis C at some point in time. Positive EIA test results must be confirmed.
- PCR - A PCR (Polymerase Chain Reaction) test measures the precise concentration, or viral load of HCV in the blood. A PCR test may be used to provide confirmation of HCV status or to monitor the effects of treatment.
- Liver Function Tests - Liver function tests look for a variety of substances in the blood that help to indicate how well the liver is able to perform its normal activities. When the liver is impaired or damaged, the levels of these substances may change. Since the virus as well as the drugs used to treat HCV may affect the liver directly, it is very important to monitor liver function on a regular basis.
- Genotype - There are at least six distinct varieties, or genotypes, of hepatitis C. The genotype of the virus may affect the course of the illness as well as the response of the virus to treatment. In addition, infection is possible with more than one genotype of HCV-greatly complicating the course of treatment. Therefore, it is important for patients to know their own genotype of HCV and to avoid exposure to other varieties of the virus.
Co-Infected individuals may also be prescribed the following tests:
- Liver Biopsy is the removal of liver tissue with a needle. Currently it is the most accurate means to assess liver inflammation and scarring - key measures of the progression of HCV-related liver disease. Such measures help physicians accurately determine the stage and cause of liver disease, plan future treatments, and assess the effectiveness of current treatments. Drawbacks of the procedure include pain, as well as rare but potentially serious complications.
- Transient Elastography is a safe and non-invasive test that uses ultrasound to measure the stiffness of liver tissue. This test, shown to correlate well with results collected via liver biopsies, is not yet FDA approved. However, active research is underway to determine the feasibility of using transient elastography as an alternative to invasive biopsies in the treatment of HCV-related liver disease.