Viral hepatitis C

Hepatitis C virus (HCV) is the cause of approximately 20% of acute hepatitis cases, 60–70% of chronic hepatitis cases, and about 30% of cirrhosis and liver cancer cases. HCV was discovered in 1989 and belongs to the RNA virus family Togaviridae, genus Flavivirus. It has a size of 40–60 nm and contains a high amount of lipids.

There are at least 6 genotypes and 50 serotypes of HCV. Knowing the genotype or serotype (specific antibodies to the genotype) is useful for making treatment recommendations and choosing therapy.

HCV is transmitted through contact with infected blood or blood products: blood transfusions, use of needles and syringes previously used by others, unsterilized or poorly sterilized equipment, tattoos, vaccinations with non-sterile instruments, and sharing toothbrushes, razors, tweezers, or manicure kits.

The virus is also present in body fluids such as saliva, breast milk, vaginal secretions, and semen — but in lower concentrations than in blood. HCV can be passed from mother to fetus. The rate of vertical transmission in pregnant women who are anti-HCV positive is estimated at 2.7–4.4%. This increases to 5.4–8.6% in pregnant women co-infected with HCV and HIV.

Approximately 85% of acute HCV infections progress to chronic form. Hepatocellular carcinoma may develop in about 20% of patients with cirrhosis (on average after 30 years), and 1–5% of these cases involve HCV infection.

The onset of the disease is often insidious, which is why the virus is sometimes referred to as a “slow-burning bomb” or a “silent killer.”

“Serological windows” — the time between initial infection and antibody detection — vary among different patients. Current immunoassays usually detect anti-HCV antibodies within 7–8 weeks after infection. In cases of spontaneous recovery, these antibodies may persist for life or gradually decline and disappear over several years. In patients with chronic infection, anti-HCV antibodies remain detectable indefinitely.

In low-risk populations, the percentage of individuals with false-negative test results (seronegative despite infection) is about 0.5–1%.

Main indications for ordering an HCV test:

• Elevated levels of ALT and AST;
• Preparation for surgery;
• Parenteral procedures;
• Planning pregnancy;
• Clinical signs of viral hepatitis;
• Unprotected sexual contacts, frequent change of sexual partners;
• Intravenous drug use;
• Cholestasis (bile flow obstruction).