Hepatitis C virus (HCV) infection
Hepatitis C virus is a bloodborne RNA virus, transmitted mainly by injection drug use, that produces mostly asymptomatic acute infection and chronic infection in 60% to 80% of cases. Diagnosis is by HCV antibody followed by HCV RNA, and direct-acting antiviral regimens cure more than 90% of patients, reducing but not eliminating the risk of cirrhosis and hepatocellular carcinoma.
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What this article covers
- Overview
A bloodborne RNA virus with a high rate of chronic progression: hepatitis C virus (HCV) infects an estimated 150 million people worldwide and, unlike hepatitis A or B, results in chronic infection in 60% to 80% of exposed people.
- Epidemiology
Approximately 150 million people are infected with HCV worldwide, making chronic HCV one of the leading causes of cirrhosis and hepatocellular carcinoma globally.
- Risk factors
Injection-drug use or intranasal illicit-drug use, ever: the leading risk factor in current epidemiology.
- Pathophysiology
Bloodborne inoculation with direct hepatocyte infection: HCV replicates in hepatocytes, with liver injury from both direct viral cytopathic effects and the host immune response.
- Clinical features
Acute infection is usually asymptomatic: most people have no recognized symptoms at the time of acute HCV acquisition, which is why most chronic infection is identified only through screening.
- Differential diagnosis
Hepatitis B virus infection: a similarly transmitted bloodborne hepatitis; HBsAg is positive in HBV and negative in isolated HCV, so a negative HBsAg excludes concurrent active HBV, though…
- Diagnosis
HCV infection is confirmed by a two-step serologic and virologic approach, not a clinical scoring system: a positive HCV antibody indicates past or current exposure and does not confer immunity, so a…
- Management
First, confirm active infection with HCV RNA and obtain genotype, and evaluate for cirrhosis with noninvasive fibrosis assessment, since regimen selection depends on genotype, treatment history, and fibrosis stage.
- Complications
Cirrhosis: develops in up to 30% of chronically infected patients over two to three decades.
- Prognosis
60% to 80% of infections become chronic, with spontaneous clearance (usually within 6 months) more likely in women, younger patients, symptomatic acute infection, high ALT, or the favorable interleukin 28B genotype.
- Prevention
Universal age-based screening: test all adults age 18 to 79 years for HCV antibody, with reflex HCV RNA testing if positive; continue risk-factor-based testing outside this age range regardless of the specific upper age limit used.
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