Hepatitis C is an infectious disease affecting the liver, caused by the hepatitis C virus (HCV). The infection is often asymptomatic, but once established, chronic infection can progress to scarring of the liver (fibrosis), and advanced scarring (cirrhosis) which is generally apparent after many years. In some cases, those with cirrhosis will go on to develop liver failure or other complications of cirrhosis, including liver cancer.
The hepatitis C virus (HCV) is spread by blood-to-blood contact. Most people have few symptoms after the initial infection, yet the virus persists in the liver in about 80% of those infected. Persistent infection can be treated with medication, such as interferon and ribavirin, and currently over half are cured overall. Those who develop cirrhosis or liver cancer may require a liver transplant, although the virus generally recurs after transplantation.
An estimated 150-200 million people worldwide are infected with hepatitis C. Apart from humans, it only infects chimpanzees. No vaccine against hepatitis C is available. The existence of hepatitis C (originally “non-A non-B hepatitis”) was postulated in the 1970s and proved conclusively in 1989. It is one of five known hepatitis viruses: A, B, C, D, and E.
Hepatitis C Transmission
Several activities and practices were initially identified as potential sources of exposure to the hepatitis C virus. More recent studies question this route of transmission. Currently it is felt to be a means of rare transmission of hepatitis C infection.
Injection drug use
Those who currently use or have used drug injection as their delivery route for illicit drugs are at increased risk for getting hepatitis C because they may be sharing needles or other drug paraphernalia (includes cookers, cotton, spoons, water, etc.), which may be contaminated with HCV-infected blood. An estimated 60% to 80% of intravenous recreational drug users in the United States have been infected with HCV. Harm reduction strategies are encouraged in many countries to reduce the spread of hepatitis C, through education, provision of clean needles and syringes, and safer injecting techniques. For reasons that are not clear transmission by this route currently appears to be declining in the US.
Drug use by nasal inhalation (Drugs that are “snorted”)
Transmission of HCV is possible through the nasal inhalation (insuffulation) of drugs when straws (containing even trace amounts of mucus and blood) are shared among users.
Blood transfusion, blood products, or organ transplantation prior to implementation of HCV screening (in the U.S., this would refer to procedures prior to 1992) is a decreasing risk factor for hepatitis C.
The virus was first isolated in 1989 and reliable tests to screen for the virus were not available until 1992. Therefore, those who received blood or blood products prior to the implementation of screening the blood supply for HCV may have been exposed to the virus. Blood products include clotting factors (taken by hemophiliacs), immunoglobulin, Rhogam, platelets, and plasma. In 2001, the Centers for Disease Control and Prevention reported that the risk of HCV infection from a unit of transfused blood in the United States is less than one per million transfused units.
Iatrogenic medical or dental exposure
People can be exposed to HCV via inadequately or improperly sterilized medical or dental equipment. Equipment that may harbor contaminated blood if improperly sterilized includes needles or syringes, hemodialysis equipment, oral hygiene instruments, and jet air guns, etc. Scrupulous use of appropriate sterilization techniques and proper disposal of used equipment can reduce the risk of iatrogenic exposure to HCV to virtually zero.
Occupational exposure to blood
Medical and dental personnel, first responders (e.g., firefighters, paramedics, emergency medical technicians, law enforcement officers), and military combat personnel can be exposed to HCV through accidental exposure to blood through accidental needlesticks or blood spatter to the eyes or open wounds. Universal precautions to protect against such accidental exposures significantly reduce the risk of exposure to HCV.
Recreational exposure to blood
Contact sports and other activities, such as “slam dancing” that may result in accidental blood-to-blood exposure are potential sources of exposure to HCV.
Sexual transmission of HCV is considered to be rare. Studies show the risk of sexual transmission in heterosexual, monogamous relationships is extremely rare or even null. The CDC does not recommend the use of condoms between long-term monogamous discordant couples (where one partner is positive and the other is negative). However, because of the high prevalence of hepatitis C, this small risk may translate into a non-trivial number of cases transmitted by sexual routes. Vaginal penetrative sex is believed to have a lower risk of transmission than sexual practices that involve higher levels of trauma to anogenital mucosa (anal penetrative sex, fisting, use of sex toys).
Body piercings and tattoos
Tattooing dyes, ink pots, stylets and piercing implements can transmit HCV-infected blood from one person to another if proper sterilization techniques are not followed. Tattoos or piercings performed before the mid 1980s, “underground,” or non-professionally are of particular concern since sterile techniques in such settings may have been or be insufficient to prevent disease. Despite these risks, it is rare for tattoos to be directly associated with HCV infection and the U.S. Centers for Disease Control and Prevention’s position on this subject states that, “no data exist in the United States indicating that persons with exposures to tattooing alone are at increased risk for HCV infection.”
Shared personal care items
Personal care items such as razors, toothbrushes, cuticle scissors, and other manicuring or pedicuring equipment can easily be contaminated with blood. Sharing such items can potentially lead to exposure to HCV. Appropriate caution should be taken regarding any medical condition which results in bleeding such as canker sores, cold sores, and immediately after flossing.
HCV is not spread through casual contact such as hugging, kissing, or sharing eating or cooking utensils.
Vertical transmission refers to the transmission of a communicable disease from an infected mother to her child during the birth process. Mother-to-child transmission of hepatitis C has been well described, but occurs relatively infrequently. Transmission occurs only among women who are HCV RNA positive at the time of delivery; the risk of transmission in this setting is approximately 6 out of 100. Among women who are both HCV and HIV positive at the time of delivery, the risk of transmitting HCV is increased to approximately 25 out of 100.
The risk of vertical transmission of HCV does not appear to be associated with method of delivery or breastfeeding.
Hepatitis C Treatment
There is a very small chance of clearing the virus spontaneously in chronic HCV carriers (0.5 to 0.74% per year), however, the majority of patients with chronic hepatitis C will not clear it without treatment.
Current treatment is a combination of pegylated interferon alpha (brand names Pegasys and PEG-Intron) and the antiviral drug ribavirin for a period of 24 or 48 weeks, depending on genotype. Indications for treatment include patients with proven hepatitis C virus infection and persistent abnormal liver function tests. Sustained cure rates (sustained viral response) of 75% or better occur in people with genotypes HCV 2 and 3 in 24 weeks of treatment, about 50% in those with genotype 1 with 48 weeks of treatment and 65% for those with genotype 4 in 48 weeks of treatment. About 80% of hepatitis C patients in the United States have genotype 1. Genotype 4 is more common in the Middle East and Africa. Should treatment with pegylated ribivirin-interferon not return a 2-log viral reduction or complete clearance of RNA (termed early virological response) after 12 weeks for genotype 1, the chance of treatment success is less than 1%. Early virological response is typically not tested for in non-genotype 1 patients, as the chances of attaining it are greater than 90%. The mechanism of action is not entirely clear, because even patients who appear to have had a sustained virological response still have actively replicating virus in their liver and peripheral blood mononuclear cells.
The evidence for treatment in genotype 6 disease is currently sparse, and the evidence that exists is for 48 weeks of treatment at the same doses as are used for genotype 1 disease. Physicians considering shorter durations of treatment (e.g., 24 weeks) should do so within the context of a clinical trial.
Treatment during the acute infection phase has much higher success rates (greater than 90%) with a shorter duration of treatment; however, this must be balanced against the 15-40% chance of spontaneous clearance without treatment (see Acute Hepatitis C section above).
Those with low initial viral loads respond much better to treatment than those with higher viral loads (greater than 400,000 IU/mL). Current combination therapy is usually supervised by physicians in the fields of gastroenterology, hepatology or infectious disease.
The treatment may be physically demanding, particularly for those with a prior history of drug or alcohol abuse. It can qualify for temporary disability in some cases. A substantial proportion of patients will experience a panoply of side effects ranging from a ‘flu-like’ syndrome (the most common, experienced for a few days after the weekly injection of interferon) to severe adverse events including anemia, cardiovascular events and psychiatric problems such as suicide or suicidal ideation. The latter are exacerbated by the general physiological stress experienced by the patient.
Current guidelines strongly recommend that hepatitis C patients be vaccinated for hepatitis A and B if they have not yet been exposed to these viruses, as infection with a second virus could worsen their liver disease.
Alcoholic beverage consumption accelerates HCV associated fibrosis and cirrhosis, and makes liver cancer more likely; insulin resistance and metabolic syndrome may similarly worsen the hepatic prognosis. There is also evidence that smoking increases the fibrosis (scarring) rate.
During pregnancy and breastfeeding
If a woman who is pregnant has risk factors for hepatitis C, she should be tested for antibodies against HCV. About 4% infants born to HCV infected women become infected. There is no treatment that can prevent this from happening. There is a high chance of the baby ridding the HCV in the first 12 months.
In a mother that also has HIV, the rate of transmission can be as high as 19%. There are currently no data to determine whether antiviral therapy reduces perinatal transmission. Ribavirin and interferons are contraindicated during pregnancy. However, avoiding fetal scalp monitoring and prolonged labor after rupture of membranes may reduce the risk of transmission to the infant.
HCV antibodies from the mother may persist in infants until 15 months of age. If an early diagnosis is desired, testing for HCV RNA can be performed between the ages of 2 and 6 months, with a repeat test done independent of the first test result. If a later diagnosis is preferred, an anti-HCV test can performed after 15 months of age. Most infants infected with HCV at the time of birth have no symptoms and do well during childhood. There is no evidence that breast-feeding spreads HCV. To be cautious, an infected mother should avoid breastfeeding if her nipples are cracked and bleeding.