How is HCV transmitted?
HCV is transmitted primarily through large or repeated percutaneous (i.e., passage through the skin) exposures to infectious blood, such as
- Injection drug use (currently the most common means of HCV transmission in the United States)
- Receipt of donated blood, blood products, and organs (once a common means of transmission but now rare in the United States since blood screening became available in 1992)
- Needlestick injuries in health care settings
- Birth to an HCV-infected mother
HCV can also be spread infrequently through
- Sex with an HCV-infected person (an inefficient means of transmission)
- Sharing personal items contaminated with infectious blood, such as razors or toothbrushes (also inefficient vectors of transmission)
- Other health care procedures that involve invasive procedures, such as injections (usually recognized in the context of outbreaks)
What is the prevalence of HCV infection among injection drug users (IDUs)?
The most recent surveys of active IDUs indicate that approximately one third of young (aged 18–30 years) IDUs are HCV-infected. Older and former IDUs typically have a much higher prevalence (approximately 70%–90%) of HCV infection, reflecting the increased risk of continued injection drug use. The high HCV prevalence among former IDUs is largely attributable to needle sharing during the 1970s and 1980s, before the risks of bloodborne viruses were widely known and before educational initiatives were implemented.
Is cocaine use associated with HCV transmission?
There are very limited epidemiologic data to suggest an additional risk from non-injection (snorted or smoked) cocaine use, but this risk is difficult to differentiate from associated injection drug use and sex with HCV-infected partners.
What is the risk of acquiring HCV infection from transfused blood or blood products in the United States?
Now that more advanced screening tests for HCV are used in blood banks, the risk is considered to be less than 1 chance per 2 million units transfused. Before 1992, when blood screening for HCV became available, blood transfusion was a leading means of HCV transmission.
Can HCV be spread during medical or dental procedures?
As long as Standard Precautions and other infection control practices are used consistently, medical and dental procedures performed in the United States generally do not pose a risk for the spread of HCV. However, HCV has been spread in health care settings when injection equipment, such as syringes, was shared between patients or when injectable medications or intravenous solutions were mishandled and became contaminated with blood. Health care personnel should understand and adhere to Standard Precautions, which includes Injection Safety practices aimed at reducing bloodborne pathogen risks for patients and health care personnel. If health care-associated HCV infection is suspected, this should be reported to state and local public health authorities.
Can HCV be spread within a household?
Yes, but this does not occur very often. If HCV is spread within a household, it is most likely a result of direct, through-the-skin exposure to the blood of an infected household member.
What are the signs and symptoms of acute HCV infection?
Persons with newly acquired HCV infection usually are asymptomatic or have mild symptoms that are unlikely to prompt a visit to a health care professional. When symptoms occur, they can include:
- Dark urine
- Clay-colored stool
- Abdominal pain
- Loss of appetite
- Joint pain
What percentage of persons infected with HCV develop symptoms of acute illness?
Approximately 20%–30% of those newly infected with HCV experience fatigue, abdominal pain, poor appetite, or jaundice.
How soon after exposure to HCV do symptoms appear?
In those persons who do develop symptoms, the average time period from exposure to symptom onset is 4–12 weeks (range: 2–24 weeks).
What are the signs and symptoms of chronic HCV infection?
Most persons with chronic HCV infection are asymptomatic. However, many have chronic liver disease, which can range from mild to severe, including cirrhosis and liver cancer. Chronic liver disease in HCV-infected persons is usually insidious, progressing slowly without any signs or symptoms for several decades. In fact, HCV infection is often not recognized until asymptomatic persons are identified as HCV-positive when screened for blood donation or when elevated alanine aminotransferase (ALT, a liver enzyme) levels are detected during routine examinations.