Hepatitis C is a viral infection that that typically leads to chronic infection in the liver. More than 185 million people worldwide are estimated to have the hepatitis C virus antibody, suggesting current infection. Central and East Asia, North Africa, and the Middle East have a high prevalence of hepatitis C with greater than 3.5% of its population affect whereas Asia-Pacific, Tropical Latin America, and North America have a lower prevalence of less than 1.5% of the population affected.
What does this mean for the United States? Despite a lower prevalence, current studies suggest that at least 3.5 million people in the United States may be affected by this virus although due to under diagnosis this number is likely an underestimate. Approximately 80% of patients with chronic hepatitis C were born between 1945 and 1965, also known as the “baby boomer” population. In other words, people born during this time have a six times higher likelihood of having hepatitis C than all other adults in the United States.
Additional risk factors for transmission includes intravenous drug use, blood transfusion, incarceration, and sexual contact with a high-risk individual. Blood transfusion had been a major risk factor for acute hepatitis C in the past with more than 10% of transfusion recipients acquiring a blood borne infection. However, donor screening that was implemented in 1990 has nearly eliminated the risk of post-transfusion acute hepatitis C with an estimated risk of less than one in a million per unit transfused.
Most people with chronic hepatitis C do not have any symptoms, so the majority of patients with an infection are unaware of having hepatitis C. The most severe complication of hepatitis C is the development of cirrhosis and decompensated liver disease that occurs in about 20% of patients over a 20 to 30 year time period. Hepatitis C is still one of the most common causes of cirrhosis leading to liver transplant in the United States.
Because hepatitis C is a chronic infection that can lead to significant liver disease, it is recommended that all persons at with risk factors for hepatitis C should undergo screening – this includes one time testing for all “baby boomers” which is defined as people born between 1945 and 1965, regardless of risk factors. In addition, hepatitis C testing is recommended for anyone with evidence of liver disease, such as elevated liver tests. Testing for hepatitis C requires a specific lab test to check for the hepatitis C antibody. If the hepatitis C antibody test is negative, no further testing is recommended. If it is positive, however, further testing with a RNA test is recommended to confirm chronic infection. Approximately 15% of people exposed to hepatitis C will spontaneously clear the infection, so despite a positive antibody test their RNA test will be negative.
The number of new cases of hepatitis C in the United States had been decreasing since the 1980’s with the advent of screening of donated blood. However, Hepatitis C infection rates have increased substantially among young adults over the last decade. There were an estimated 33,900 new infections diagnosed in 2015 which is nearly a three times higher than new cases diagnosed in 2010. This increase most likely reflects the epidemic of opioid and injection drug use that is on the rise in the United States.
In order to prevent transmission of hepatitis C in persons who share a household with a patient with hepatitis C, it is recommended to avoid sharing razors and toothbrushes or other items or activities that would allow blood to blood exposure. Close contact such as hugging does not increase risk of transmission. Transmission does not occur with kissing, sneezing, coughing, or casual contact. Typical household activities such as sharing food, water, eating utensils, or drinking glasses also does not cause transmission of hepatitis C.
Treatment of hepatitis C has dramatically changed over the last 3 years with the approval of direct acting antiviral (DAA) agents. The first of these agents were approved in 2013 although it was not until 2014 when the DAA’s were all oral medications and did not require concomitant use of interferon that is an injection medication with many side effects. There have been a total of 9 agents approved by the FDA that have all shown greatly improved efficacy to eradicate hepatitis C compared to the previously used interferon and ribavirin regimen. Most patients will undergo 8 to 12 weeks of treatment with a high chance of achieving a sustained virologic response, or SVR. SVR is defined as an undetectable virus level 12 weeks after treatment is completed and is considered a virologic cure from hepatitis C. Achieving an SVR has been shown to be durable which means patients stay virus negative years after completing therapy. However, patients can get reinfected with hepatitis C again as having the hepatitis C antibody does not prevent a new infection if reexposure to the virus occurs.
Patients who have underlying cirrhosis also have a high chance of clearing hepatitis C with the DAA’s although their treatment duration will be a little bit longer. However, these patients will require continued screening for liver cancer as the underlying cirrhosis is unlikely to be cured. Any patient with cirrhosis regardless of underlying cause has a 5% yearly risk of developing liver cancer so imaging every 6 months is recommended.
With increased awareness of risk factors for hepatitis C, more patients can be diagnosed and treated. The newer treatments are extremely effective with minimal side effects, so a future without hepatitis C is on the horizon.