What Is Hepatitis C?
Five different viruses (termed A,B,C,D, and E) cause viral hepatitis. Three other viruses that cause hepatitis have been identified, but not much is known about them. Hepatitis C virus (HCV) is known to account for the great majority of what was previously referred to as non-A, non-B hepatitis. The hepatitis C virus was identified and described in 1989, and in 1990 a hepatitis C antibody test (anti-HCV) became commercially available to help identify individuals exposed to HCV.
How Will I Know If I Have Hepatitis C?
In general, individuals infected with HCV are often identified because they are found to have elevated liver enzymes on a routine blood test or because a hepatitis C antibody is found to be positive at the time of blood donation. In 1992, a more specific test for anti-HCV became available and eliminated some of the false positive reactions that were previously troublesome. In general, elevated liver enzymes and a positive antibody test for HCV (anti-HCV) means that an individual has chronic hepatitis C. However, the anti-HCV may remain positive for several years after recovery from acute hepatitis C. A small percentage of patients still may have false positive hepatitis C antibody reactions. In these two cases, liver enzymes are typically normal.
It appears that the formation of antibodies in response to the virus (associated with immunity in other forms of viral infections) does not apply with hepatitis C. Researchers believe this is because the virus changes to new forms of the original virus which caused the body to produce antibodies. It is estimated that up to 85% of the 150,000 people infected with the hepatitis C virus each year will develop chronic hepatitis. There are 3.5 million Americans chronically infected with HCV.
Can I Give The Disease To Others?
HCV can be transmitted through blood transfusions. However, all blood is now tested for the presence of this virus by the antibody test. It is estimated that the risk of post-transfusion hepatitis C has been reduced from the 8-10% frequency of infection several years ago to less than 0.5%. Other individuals who may come in contact with infected blood, instruments, or needles, such as l.V. drug users, health care workers or laboratory technicians are also at risk of acquiring hepatitis C. Currently, there is no vaccine available to immunize individuals against this virus.
The risk for transmitting hepatitis C sexually is unknown. There have been rare, documented cases of people with chronic hepatitis C transmitting the virus to their only, long-term sexual partner. The Centers For Disease Control and Prevention (CDC) says that because of the lack of sufficient information those with only one, long term sexual partner need not change their sexual practices. Many physicians who counsel patients with hepatitis C recommend the same thing to those in a monogamous relationship. CDC says there is an increased risk of becoming infected with hepatitis C if you have multiple sex partners. Whether the use of latex condoms is 100% effective in preventing someone from infecting their sexual partner or becoming infected is uncertain.
What Is The Natural History Of Hepatitis C?
Specific information regarding the natural history of hepatitis C is not yet available. In general, however, chronic hepatitis C appears to be a slowly progressive disease that may gradually advance over 10-40 years. There is some evidence that the disease may progress faster when acquired in middle age or older. In one study, chronic hepatitis by liver biopsy was identified on the average of 10 years following blood transfusions and cirrhosis on an average of 20 years. It also appears that HCV, like the hepatitis B virus, is associated with an increased chance of developing hepatocellular carcinoma, a type of primary liver cancer. Almost all HCV-related liver cancer occurs with cirrhosis (scarring) of the liver. The exact magnitude of this risk is unknown but appears to be a late risk factor occurring on the average of 30 years after the time of infection. This is more prevalent in the Far East than in the U.S.
Is There A Treatment For Chronic Hepatitis C?
The drug, interferon alpha-2b, has been approved for the treatment of chronic hepatitis C. Approximately 40% of patients treated for six months with interferon will respond, showing major improvement or normalization of liver tests and reduced inflammation on liver biopsy. However, of those who respond to treatment, approximately 60% will suffer a relapse during several months after interferon treatment is discontinued. Thus, only 10-15% of patients treated with interferon have a sustained, long lasting response. Patients can be treated a second time and 85% of patients will enter a second remission; however, the duration of treatment and dosage required for long-term remission in this group of patients has yet to be determined. In a recent multi-center trial in Europe 44% of the hepatitis C patients on the standard dosage for 18 months had their elevated liver enzymes return to normal. This group was evaluated 19 to 42 months after this initial 18 month therapy and half of them (22%) still had normal liver enzymes. The hope is that improvement or normalization of liver tests and reduced inflammation in the liver will slow or interrupt the development of progressive liver disease. However, the true impact of interferon treatment on the long-term course of chronic hepatitis C and survival is unknown.
Side effects caused by interferon therapy are frequent and include “flu-like” symptoms, depression, headache, and decreased appetite. The “flu-like” symptoms can be minimized by taking two doses of acetaminophen (e.g. Tylenol). In addition, interferon may depress the bone marrow leading to difficulties with the white blood cells and platelets. Frequent blood tests are needed to monitor white blood cells, platelets and liver enzymes. A liver biopsy is typically done prior to treatment to determine the severity of liver damage and provide confirmation of the underlying disease.