HEPATITIS C

What is it?

Hepatitis C is a viral infection of the liver which had been referred to as parenterally transmitted or "non-A, non-B" hepatitis until identification of the causative agent in 1989. The discovery and characterization of the hepatitis C virus led to the understanding of its primary role in post-transfusion hepatitis and its tendency to induce persistent infection.

Hepatitis C has been identified as the most common cause of post-transfusion hepatitis worldwide, accounting for approximately 90% of this disease in Japan, USA and Western Europe.

Who gets it?

HCV infection is widespread throughout the world. WHO has recently published the first global estimate of HCV prevalence, which suggests that up to 3% of the world's population has been infected with HCV. There may be more than 170 million chronic carriers at risk of developing liver cirrhosis and/or liver cancer. Published studies on the prevalence of hepatitis C in various subgroups of the population worldwide showed rates from 0% to 70%: in many countries, for example, the prevalence of HCV is very high among drug users.

What are the symptoms?

In acute infections, the most common symptoms are fatigue and jaundice; however, the vast majority of cases (up to 90%), even those with chronic disease, are asymptomatic.

It is estimated today that about 20% of patients with chronic infections develop cirrhosis, and that 1% to 5% of cirrhotic individuals will develop cancer of the liver during the next 10 years.

Hepatitis C exacerbates the severity of underlying liver disease when it coexists with other hepatic conditions. About 40% to 60% of alcoholics with cirrhosis are infected with HCV, whereas only 5% to 20% of alcoholics without liver pathology have anti-HCV antibodies.

Another important complication of hepatitis C infection is cancer of the liver (primary hepatocellular carcinoma, HCC). Most patients suffering from HCC in the absence of hepatitis B infection have evidence of hepatitis C infection. The mechanisms by which HCV infection leads to liver cancer are still unclear.

What test will the Doctor want to do?

HCV is diagnosed serologically by detection of specific antibodies by means of the enzyme immunosorbent assay (EIA). However, false positives are common in first generation tests whereas second generation EIAs have substantially reduced false positive results. Therefore, supplementary tests such as the recombinant immunoblot assay (RIBA) must be carried out when possible. The presence of HCV RNA in serum indicates the presence of active infection and a potential for transmission of the infection and/or the development of chronic liver disease.

What is the treatment?

Treatment with interferon is effective in about 20% of patients. Ribavirin shows some promise as an antiviral agent against HCV when used in combination with interferon, but does not appear to be effective when used alone. Studies on combination therapy are under way, but the cost of such treatment will be high. There is no evidence that glucosteroids are beneficial.

Measures to prevent HCV infection include:

• Universal screening of blood and blood products;
• Effective use of universal precautions and barrier techniques (such as the use of sterile equipment and the wearing of gloves);
• Destruction of disposable needles and adequate sterilization of reusable material such as surgical or dental instruments;
• Promotion of public education about the risks of using unsterilized material.

There is no vaccine against HCV. Research is in progress but the high mutability of hepatitis C genome complicates its development. Lack of knowledge of any protective immune response following HCV infection also impedes vaccine research. It is not known whether the immune system is able to eliminate this virus. Some studies, however, have shown the presence of virus-neutralizing antibodies in patients with HCV infection. In the absence of a vaccine, all precautions to prevent infection by other means must be taken.