Hepatitis C Virus (HCV) is a liver infection caused by a small, enveloped RNA virus belonging to the Flaviviridae family. This virus can lead to both acute and chronic liver disease, ranging from mild illness to severe, lifelong conditions like cirrhosis and liver cancer. Understanding how HCV spreads is important for preventing its transmission and mitigating its impact on public health.
Main Pathways of Transmission
HCV is a blood-borne virus, spreading through contact with infected blood. The most frequent way this occurs is through sharing contaminated needles, syringes, or other equipment used for injecting drugs. The virus is highly infectious and can survive on dry surfaces and equipment for up to six weeks, even in amounts too small to be seen. This makes equipment like cookers, cotton, water, and ties potential sources of transmission if shared.
Transmission can also occur through unsafe medical procedures, particularly in healthcare settings where sterilization practices are not strictly followed. Before widespread screening began in the early 1990s, blood transfusions and organ transplants were significant routes of HCV transmission. Current practices now include screening blood and organ donors for HCV RNA and antibodies, which has made these types of transmissions rare in developed countries.
Healthcare professionals also face an occupational risk of HCV infection, mainly through accidental percutaneous exposure, such as needle sticks contaminated with infected blood. While other body fluids like saliva, semen, and menstrual fluid can contain HCV RNA, percutaneous exposure to blood is the most common occupational transmission route.
Other Transmission Considerations
Sexual transmission of HCV is possible but is less efficient than blood-to-blood contact. The risk is low for heterosexual couples in long-term monogamous relationships. However, factors such as multiple sex partners, co-infection with HIV, and engaging in sexual practices that may cause bleeding or mucosal trauma, like anal sex, can increase this risk. Sexually transmitted infections (STIs) that cause sores, such as herpes or syphilis, can also facilitate transmission by providing a route for the virus to enter.
HCV can also pass from an infected mother to her baby during pregnancy or childbirth, known as mother-to-child transmission. This occurs in a small percentage of pregnancies when the mother has an active HCV infection. Higher maternal viral loads, maternal injection drug use, and co-infection with HIV are associated with an increased risk of transmission. While the exact timing is not fully understood, most infections are thought to be acquired in utero or during delivery.
Although rare, HCV can be transmitted through sharing personal items that might be contaminated with blood. This includes items like razors, toothbrushes, and nail clippers. Casual contact, such as hugging, kissing, or sharing food or eating utensils, does not transmit HCV. Additionally, tattooing and body piercing can pose a risk if performed in unregulated settings using unsterilized equipment.
Strategies for Prevention
Preventing HCV transmission involves avoiding direct contact with infected blood. For individuals who inject drugs, using new, sterile needles and syringes for every injection is recommended. Harm reduction programs, such as syringe service programs, provide access to sterile equipment and education on safer injection practices, which can significantly reduce transmission rates. These programs also offer services like medication-assisted treatment that can help reduce injection drug use.
In healthcare settings, strict adherence to sterile equipment and infection control practices is essential to prevent HCV transmission. This includes proper sterilization of medical and dental instruments. Blood and organ donation centers screen all donations for HCV RNA and antibodies, preventing transmission through these routes.
To prevent household transmission, individuals should avoid sharing personal items that might have come into contact with blood, such as razors, toothbrushes, or nail clippers. Any cuts or open sores should be covered to prevent the spread of infectious blood. If blood spills occur, they should be cleaned promptly with a bleach solution (one part household bleach to ten parts water) while wearing gloves.
While sexual transmission is less efficient, using latex condoms correctly can reduce the risk, particularly for individuals with multiple partners or co-infections like HIV. Avoiding sexual activities that may cause bleeding or mucosal trauma also helps to lower the risk. Regular HCV testing is recommended for all adults aged 18 and older at least once in their lifetime, and for all pregnant women during each pregnancy. Individuals with ongoing risk factors, such as those who currently inject drugs or have certain medical conditions, should undergo periodic testing.