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Hepatitis C virus infection in the United States
1Hepatitis Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Insights
Hepatitis C virus (HCV) transmission in the US is now primarily linked to intravenous drug use (IVDU), accounting for 60% of cases. Prevention efforts must focus on reducing IVDU and identifying infected individuals for treatment.
Area of Science:
- Epidemiology
- Infectious Diseases
- Public Health
Background:
- Hepatitis C virus (HCV) is the most common chronic bloodborne infection in the US, predominantly affecting individuals under 50.
- Transmission routes for HCV have shifted, with blood transfusions decreasing in importance and intravenous drug use (IVDU) becoming the primary mode of transmission.
Purpose of the Study:
- To analyze the changing dynamics of HCV transmission in the United States.
- To identify key risk factors and sources of HCV infection.
- To inform strategies for reducing the burden of HCV infection and disease.
Main Methods:
- Review of epidemiological data on HCV transmission sources.
- Analysis of case-control studies to identify associated exposures.
- Evaluation of current prevention and surveillance strategies.
Main Results:
- Intravenous drug use (IVDU) is responsible for 60% of current HCV transmissions, a significant increase over time.
- Blood transfusions, once a major source, now account for few recent infections.
- Sexual exposures account for up to 20%, with other sources (occupational, hemodialysis, etc.) comprising about 10%.
Conclusions:
- Effective HCV control requires prioritizing primary prevention to reduce transmission, particularly among IVDU.
- Secondary prevention through early identification and treatment of HCV-infected individuals is crucial for managing chronic liver disease.
- Ongoing surveillance and program evaluation are essential to monitor incidence and assess the effectiveness of interventions.
Abstract:
Hepatitis C virus (HCV) infection is the most common chronic bloodborne infection in the United States, and most infected persons are younger than 50 years old. The relative importance of the two most common exposures associated with transmission of HCV, blood transfusion and intravenous drug use (IVDU), has changed over time. Blood transfusion, which accounted for a substantial proportion of HCV infections acquired >10 years ago, rarely accounts for recently acquired infections. In contrast, IVDU has consistently accounted for a substantial proportion of HCV infections and currently accounts for 60% of HCV transmission while sexual exposures account for up to 20%. Other known exposures (occupational, hemodialysis, household, perinatal) together account for about 10% of infections. In the remaining 10%, no recognized source of infection can be identified, although most persons in this category are associated with low socioeconomic level. Case-control studies have found no association with military service or exposures resulting from medical, surgical or dental procedures, tattooing, acupuncture, ear piercing or foreign travel. Reducing the burden of HCV infection and disease in the United States requires implementation of primary prevention activities that reduce or eliminate HCV transmission and secondary prevention activities that reduce liver and other chronic diseases in HCV-infected persons by identifying them and providing appropriate medical management and antiviral therapy. Surveillance and evaluation activities also are important to determine the effectiveness of these programs in reducing the incidence of disease, identifying persons infected with HCV, and promoting healthy lifestyles and behaviors.