hepatitis C

hepatitis C
Name	Hepatitis C
Synonyms	HCV
Caption	An illustration of the hepatitis C virus particle.
Field	Infectious disease, hepatology
Symptoms	Often none initially; can include jaundice, fatigue, abdominal pain
Complications	Cirrhosis, hepatocellular carcinoma, liver failure
Onset	2 weeks to 6 months after exposure
Duration	Acute (short-term) or chronic (lifelong)
Causes	Infection by the hepatitis C virus
Risks	Intravenous drug use, unsafe medical procedures, blood transfusion before 1992
Diagnosis	Blood test for anti-HCV antibodies, HCV RNA
Prevention	Harm reduction, screening of blood donations, sterile equipment
Treatment	Antiviral medications (e.g., sofosbuvir, ledipasvir)
Medication	Direct-acting antivirals
Prognosis	Often curable with treatment
Frequency	~58 million globally (chronic infections)
Deaths	~290,000 annually

hepatitis C is a viral infection primarily affecting the liver, caused by the hepatitis C virus. The disease manifests as an acute illness but frequently progresses to a chronic state, posing a significant risk for severe hepatic complications. It represents a major global public health challenge, with transmission occurring predominantly through exposure to infected blood. Advances in antiviral therapy have transformed its management, offering high cure rates for most patients.

Signs and symptoms

Most individuals with acute infection are asymptomatic or experience only mild, non-specific illness. When present, symptoms may include fatigue, nausea, abdominal pain, loss of appetite, and jaundice, a yellowing of the skin and eyes. The acute phase typically resolves spontaneously in 15-25% of cases, but the majority develop a persistent, chronic infection. Chronic hepatitis C often progresses silently for decades, with symptoms frequently emerging only after significant liver damage has occurred. Late-stage complications can present with signs of portal hypertension, such as ascites and variceal bleeding, or symptoms related to hepatocellular carcinoma. Extrahepatic manifestations, including cryoglobulinemia and glomerulonephritis, are also associated with chronic infection.

Causes and transmission

The causative agent is the hepatitis C virus, a small, enveloped, positive-sense single-stranded RNA virus classified within the genus *Hepacivirus* in the family Flaviviridae. The primary mode of transmission is parenteral exposure to infected blood. Historically, a major route was through unscreened blood transfusions and blood products, a risk dramatically reduced in nations like the United States following the implementation of universal screening in the early 1990s. Currently, the most common transmission route globally is sharing equipment for injection drug use. Other risks include unsafe medical or cosmetic injections, needlestick injuries in healthcare settings, and, less commonly, from an infected mother to her child during childbirth. Sexual transmission is considered inefficient but is reported among men who have sex with men, particularly those with HIV.

Diagnosis

Diagnosis is established through serological and virological blood tests. Initial screening typically involves testing for anti-HCV antibodies using an enzyme immunoassay. A positive antibody test indicates exposure but cannot distinguish between current or resolved infection. Confirmation of active, ongoing infection requires detection of viral genetic material via an HCV RNA test, such as polymerase chain reaction (PCR). Following confirmation, assessment of the specific viral genotype (e.g., genotype 1) is crucial for guiding treatment selection. Further evaluation includes tests of liver function, such as alanine transaminase levels, and imaging studies like ultrasound or FibroScan to assess for fibrosis or cirrhosis. In some cases, a liver biopsy may be performed.

Prevention

No approved vaccine for hepatitis C exists, making prevention reliant on reducing exposure risks. Critical strategies include screening all blood donations and organ tissues, as mandated by agencies like the World Health Organization and the Food and Drug Administration. Harm reduction programs are essential, including providing sterile equipment through needle and syringe programmes and offering opioid agonist therapy. In healthcare settings, strict adherence to universal precautions and safe injection practices is mandatory. For individuals with chronic infection, counseling on preventing transmission to others and vaccination against hepatitis A and hepatitis B is recommended to prevent additional liver injury.

Treatment

The treatment landscape was revolutionized by the development of direct-acting antiviral (DAA) medications. These oral regimens, such as combinations of sofosbuvir/ledipasvir or glecaprevir/pibrentasvir, target specific viral proteins and typically have cure rates exceeding 95%. Treatment is usually short (8-12 weeks), has minimal side effects, and is effective across all major genotypes. Prior to DAAs, standard therapy involved pegylated interferon and ribavirin, which had lower efficacy and significant toxicity. The goal of DAA therapy is to achieve a sustained virological response, which is functionally considered a cure. Management also includes monitoring for and treating complications of advanced liver disease.

Epidemiology

The World Health Organization estimates approximately 58 million people globally have chronic infection, with about 1.5 million new infections occurring annually. The highest prevalence rates are found in regions including Eastern Mediterranean and Europe. In the United States, the Centers for Disease Control and Prevention reports millions have been infected, with a significant burden among the baby boomer generation born between 1945 and 1965. Incidence is closely tied to the opioid epidemic, with rising rates among young adults practicing injection drug use. Hepatitis C contributes to a substantial mortality burden, causing an estimated 290,000 deaths yearly, primarily from cirrhosis and hepatocellular carcinoma.

Category:Hepatitis Category:Viral diseases Category:Infectious diseases