Overview

Hepatitis C is a bloodborne viral infection that primarily affects the liver. It is caused by the hepatitis C virus (HCV). Many people who become infected have no symptoms for years, so the infection may remain unrecognized until routine testing, advanced liver disease, or incidental findings prompt investigation. When infection persists beyond the acute phase it is described as chronic hepatitis C, which can lead to progressive liver injury, fibrosis and eventually cirrhosis, liver failure or hepatocellular carcinoma.

Virus, genotypes and natural history

HCV is an RNA virus with several genetic groups commonly called genotypes. These genotypes differ in distribution and historically influenced treatment choices and duration. After a person is exposed some clear the virus spontaneously, while a substantial proportion develop chronic infection. The pace of liver damage varies between individuals and is influenced by factors such as age at infection, alcohol use, coexisting liver disease, and co-infection with viruses such as HIV. Over many years, repeated cycles of inflammation and repair produce scar tissue (fibrosis) that can progress to cirrhosis and raise the risk of liver-related complications.

Transmission and risk factors

HCV is transmitted when blood from an infected person enters another person's bloodstream. The most important risk remains sharing needles or other injecting equipment during recreational drug use. Other routes include unsafe medical or dental procedures involving nonsterile instruments, unregulated tattooing or piercing practices, and, historically, transfusion of unscreened blood products; modern blood screening has greatly reduced transfusion risk. Vertical transmission from mother to baby can occur around the time of birth, and sexual transmission is possible though generally less efficient; the risk is increased in certain settings, such as the presence of multiple partners, sexually transmitted infections, or HIV co-infection. Awareness of these avenues of spread is central to prevention measures.

Clinical features, diagnosis and staging

Most people with acute HCV infection have mild or nonspecific symptoms, such as fatigue, nausea, abdominal discomfort or jaundice, and many remain asymptomatic. Because clinical features are often absent or subtle, diagnosis depends on laboratory testing. Typical testing begins with a blood test for antibodies to HCV to detect prior exposure; a positive antibody test is followed by a nucleic acid (RNA) test to confirm active infection and to measure viral load. Liver health is assessed using blood tests (liver enzymes and panels for synthetic function), noninvasive fibrosis tests and imaging. In selected cases, or when noninvasive tests are inconclusive, a liver biopsy may be performed to evaluate the extent of damage.

Treatment and outcomes

Treatment of hepatitis C has advanced rapidly with the development of oral direct-acting antiviral (DAA) agents that target viral proteins required for replication. These regimens are generally well tolerated and can eradicate detectable virus in a high proportion of treated people; cure rates often exceed 90% in many treatment settings. Older regimens of pegylated interferon with ribavirin, once the mainstay of therapy, were less effective and associated with frequent side effects; some sources report cure rates in the 50–80% range for those older approaches. People with advanced liver disease may still require specialist care and, in cases of liver failure or cancer, liver transplantation. Post-transplant management includes measures to prevent or treat recurrent HCV infection when necessary.

Prevention and control

There is currently no licensed vaccine that prevents hepatitis C, so prevention focuses on reducing exposure to infected blood and providing access to diagnosis and treatment. Harm reduction measures—such as needle and syringe programmes, opioid substitution therapy and safe injecting education—reduce transmission among people who inject drugs. Rigorous infection control in healthcare and regulated body-modification practices reduce iatrogenic transmission. Screening of donated blood and organ transplants has dramatically lowered transfusion-related cases. For individuals, preventing transmission includes avoiding sharing razors or toothbrushes that may be contaminated with blood and following medical guidance during pregnancy or invasive procedures.

Screening, public health and burden

Public health strategies vary by country, but the goals are shared: to identify undiagnosed infections, link people to effective treatment and reduce transmission. Many health authorities recommend targeted screening of people with risk factors and, in some regions, broader or universal screening approaches to find asymptomatic infections. Globally, estimates suggest tens of millions of people are living with chronic HCV infection, making it a major cause of liver disease worldwide. Improved access to curative treatment and prevention programmes are key components of efforts to reduce morbidity and mortality from hepatitis C.

History and research

Recognition of a distinct post-transfusion and non-A, non-B hepatitis agent began in the 1970s; the hepatitis C virus itself was identified in 1989. Since then, advances in blood safety, diagnostics, antiviral therapy and harm reduction have transformed the clinical and public health landscape. Ongoing research seeks improved vaccines, simplified diagnostic pathways, strategies to eliminate viral hepatitis as a public health problem, and interventions to close gaps in access to care.

Key points and practical considerations

  • Cause: HCV is the virus responsible; infection is bloodborne and primarily affects the liver.
  • Symptoms: Often absent initially; when present they are usually nonspecific.
  • Diagnosis: Antibody screening followed by RNA testing to confirm active infection; liver assessment for staging.
  • Treatment: Modern oral direct-acting antivirals cure the majority of treated people; older interferon-based treatments were less effective.
  • Prevention: No vaccine; emphasis on harm reduction, infection control, safe medical and cosmetic practices and blood screening (see blood safety).
  • Public health: Screening programmes, access to treatment and education are central to reducing disease burden.

For reliable clinical guidance, prevention advice and up-to-date epidemiological data consult authoritative resources and public health agencies: general overviews, liver health information, detailed virology references, definitions of chronic infection, material on cirrhosis and complications, resources on portal hypertension and variceal bleeding, information about blood safety and ongoing vaccine research.