The Hepatitis C virus (HCV) causes a liver infection known as hepatitis. This condition can be a mild, short-term illness or develop into a serious, lifelong disease. Globally, an estimated 50 million people have chronic hepatitis C. While some individuals clear the infection on their own, a majority develop a chronic form that is a major cause of chronic liver disease.
HCV Transmission Methods
Hepatitis C is a bloodborne virus, spreading through contact with the blood of an infected person. The most common way the virus is transmitted in the United States is through sharing needles, syringes, or other equipment used to prepare and inject drugs.
Beyond injection drug use, other routes of transmission exist. Receiving tattoos or body piercings in unregulated settings where needles are not properly sterilized poses a risk. Healthcare workers can be exposed through accidental needlestick injuries. It is also possible for the virus to be passed from a mother to her baby during childbirth.
Sexual transmission of HCV can occur but is an uncommon route. The risk increases in situations that may lead to blood exposure, such as sex during menstruation. HCV is not spread through casual contact like hugging, kissing, sharing utensils or food, or by mosquito bites.
Acute and Chronic Infection Stages
HCV infection unfolds in two distinct phases: acute and chronic. The acute stage encompasses the first six months after exposure to the virus. During this period, the infection is often silent, as most people do not experience any symptoms. If symptoms do appear, they are mild and non-specific, such as fatigue, fever, and muscle aches.
About 15% to 45% of individuals will successfully clear the virus on their own within those first six months. However, the majority, between 55% and 85% of people, will not clear the virus and will progress to the chronic stage. Chronic hepatitis C is a long-term illness that persists when the body is unable to get rid of the virus.
Untreated chronic HCV can lead to severe health problems over many years. The persistent inflammation can lead to the gradual scarring of the liver, a condition known as cirrhosis. An estimated 15% to 30% of people with chronic infection will develop cirrhosis within 20 years. Cirrhosis disrupts the liver’s function, potentially leading to liver failure or a type of liver cancer called hepatocellular carcinoma.
Diagnostic Testing for HCV
Diagnosing a Hepatitis C infection involves a two-step process. The initial step is a screening test that looks for HCV antibodies in the blood, called an anti-HCV test. These antibodies are proteins the immune system produces in response to an infection. A positive result indicates a person has been exposed to the virus at some point.
A positive antibody test alone does not confirm an active infection, as antibodies remain even if the body has cleared the virus. Therefore, a second, confirmatory test is required. This follow-up is a molecular test known as a nucleic acid test (NAT) for HCV RNA.
The NAT detects the presence of the virus’s genetic material (RNA) in the bloodstream. A positive HCV RNA result confirms that the virus is currently active in the body and requires treatment. A negative RNA result after a positive antibody test means the person was infected in the past but has since cleared the virus.
Modern Antiviral Treatments
The landscape of Hepatitis C treatment has improved with the development of direct-acting antivirals, or DAAs. These medications are an advancement over older, interferon-based therapies, which were less effective and caused numerous side effects. Today, HCV is considered a curable disease for most people who undergo treatment with these drugs.
DAAs are oral medications taken for 8 to 12 weeks. These drugs work by directly targeting specific proteins of the Hepatitis C virus, which stops the virus from replicating and allows the body to clear the infection. These treatment regimens are much shorter and better tolerated than previous options.
The effectiveness of these treatments is high, with cure rates exceeding 95% in most patient populations. A “cure” is defined as a sustained virologic response (SVR), which means the virus is not detectable in the blood 12 weeks after treatment has finished. The high cure rates of DAAs have made it possible to prevent the long-term liver damage associated with chronic infection.