Because the clinical characteristics are similar for all types of acute viral hepatitis, the specific viral cause of illness cannot be determined solely on the basis of signs, symptoms, history, or current risk factors, but must be verified by specific serologic testing. For specific serologic tests required to meet the case definition, see the following link:

• Hepatitis C Virus Infection, Acute

Laboratory testing is required for confirmation of the etiologic cause of viral hepatitis. For specific serologic tests, see the following link:

• Hepatitis C Virus Infection, Past or Present

Yes. See the Guidelines for Viral Hepatitis Surveillance and Case Management, available at /hepatitis/SurveillanceGuidlines.htm.

Although only 802 cases of confirmed acute hepatitis C were reported in the United States in 2006, CDC estimates that approximately 19,000 new HCV infections occurred that year, after adjusting for asymptomatic infection and underreporting. Persons newly infected with HCV are usually asymptomatic, so acute hepatitis C is rarely identified or reported.

Approximately 3.2 million persons in the United States have chronic HCV infection. Infection is most prevalent among those born during 1945–1965, the majority of whom were likely infected during the 1970s and 1980s when rates were highest.

The following persons are at known to be at increased risk for HCV infection:

• Current or former injection drug users, including those who injected only once many years ago
• Recipients of clotting factor concentrates made before 1987, when more advanced methods for manufacturing those products were developed
• Recipients of blood transfusions or solid organ transplants before July 1992, when better testing of blood donors became available
• Chronic hemodialysis patients
• Persons with known exposures to HCV, such as
  • healthcare workers after needlesticks involving HCV-positive blood
  • recipients of blood or organs from a donor who tested HCV-positive
• Persons with HIV infection
• Children born to HCV-positive mothers
  

Yes. Approximately 15%–25% of persons clear the virus from their bodies without treatment and do not develop chronic infection; the reasons for this are not well known.

HCV infection becomes chronic in approximately 75%–85% of cases.

A person infected with HCV mounts an immune response to the virus, but replication of the virus during infection can result in changes that evade the immune response. This may explain how the virus establishes and maintains chronic infection.

Of every 100 persons infected with HCV, approximately

• 75–85 will go on to develop chronic infection
• 60–70 will go on to develop chronic liver disease
• 5–20 will go on to develop cirrhosis over a period of 20–30 years
• 1–5 will die from the consequences of chronic infection (liver cancer or cirrhosis)
  

Yes. Prior infection with HCV does not protect against later infection with the same or different genotypes of the virus. This is because persons infected with HCV typically have an ineffective immune response due to changes in the virus during infection. For the same reason, no effective pre- or postexposure prophylaxis (i.e., immune globulin) is available.

Yes. Chronic HCV infection is the leading indication for liver transplants in the United States.

Chronic HCV infection accounts for an estimated 8,000–10,000 deaths each year in the United States.

No vaccine for hepatitis C is available. Research into the development of a vaccine is under way.

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 healthcare 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 healthcare procedures that involve invasive procedures, such as injections (usually recognized in the context of outbreaks)

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.

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.

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.

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 healthcare 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. Healthcare personnel should understand and adhere to Standard Precautions, which includes safe injection practices and other guidance aimed at reducing bloodborne pathogen risks for patients and healthcare personnel. If healthcare-associated HCV infection is suspected, this should be reported to state and local public health authorities.

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.

Persons with newly acquired HCV infection usually are asymptomatic or have mild symptoms that are unlikely to prompt a visit to a healthcare professional. When symptoms occur, they can include

• Fever
• Fatigue
• Dark urine
• Clay-colored stool
• Abdominal pain
• Loss of appetite
• Nausea
• Vomiting
• Joint pain
• Jaundice

Approximately 20%–30% of those newly infected with HCV experience fatigue, abdominal pain, poor appetite, or jaundice.

In those persons who do develop symptoms, the average time period from exposure to symptom onset is 4–12 weeks (range: 2–24 weeks).

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.

HCV testing is recommended for anyone at increased risk for HCV infection, including:

• Persons who have ever injected illegal drugs, including those who injected only once many years ago
• Recipients of clotting factor concentrates made before 1987
• Recipients of blood transfusions or solid organ transplants before July 1992
• Patients who have ever received long-term hemodialysis treatment
• Persons with known exposures to HCV, such as
  • healthcare workers after needlesticks involving HCV-positive blood
  • recipients of blood or organs from a donor who later tested HCV-positive
• All persons with HIV infection
• Patients with signs or symptoms of liver disease (e.g., abnormal liver enzyme tests)
• Children born to HCV-positive mothers (to avoid detecting maternal antibody, these children should not be tested before age 18 months)
  

Several blood tests are performed to test for HCV infection, including:

• Screening tests for antibody to HCV (anti-HCV)
  • enzyme immunoassay (EIA)
  • enhanced chemiluminescence immunoassay (CIA)
• Recombinant immunoblot assay (RIBA)
• Qualitative tests to detect presence or absence of virus (HCV RNA polymerase chain reaction [PCR])
• Quantitative tests to detect amount (titer) of virus (HCV RNA PCR)
  

A table on the interpretation of HCV test results is available at http://www.cdc.gov/hepatitis/HCV/PDFs/hcv_graph.pdf.

A flow chart on HCV infection testing for diagnosis is available at http://www.cdc.gov/hepatitis/HCV/PDFs/hcv_flow.pdf.

HCV infection can be detected by anti-HCV screening tests (enzyme immunoassay) 4–10 weeks after infection. Anti-HCV can be detected in >97% of persons by 6 months after exposure.

HCV RNA appears in blood and can be detected as early as 2–3 weeks after infection.

False-positive anti-HCV tests appear more often when persons at low risk for HCV infection (e.g., blood donors) are tested. Therefore, it is important to confirm a positive anti-HCV test with a supplemental test, such as RIBA (recombinant immunoblot assay), as most false positive anti-HCV tests are reported as negative on supplemental testing. More information is available from the Guidelines for Laboratory Testing and Result Reporting of Antibody to Hepatitis C Virus.

Persons with early HCV infection might not yet have developed antibody levels high enough that the test can measure. In addition, some persons might lack the (immune) response necessary for the test to work well. In these persons, further testing such as PCR for HCV RNA may be considered.

The level of ALT (alanine aminotransferase, a liver enzyme) in the blood should be measured. An elevated ALT indicates inflammation of the liver. The patient should be checked further for chronic liver disease and possible treatment. The evaluation should be performed by a healthcare professional familiar with chronic hepatitis C.

Yes. It is common for patients with chronic hepatitis C to have liver enzyme levels that go up and down, with periodic returns to normal or near normal levels. Liver enzyme levels can remain normal for over a year despite chronic liver disease.

HCV-positive persons should be evaluated (by referral or consultation, if appropriate) for presence of chronic liver disease, including assessment of liver function tests, evaluation for severity of liver disease and possible treatment, and determination of the need for hepatitis A and hepatitis B vaccination.

Any physician who manages a person with hepatitis C should be knowledgeable and current on all aspects of the care of a person with hepatitis C; this can include some internal medicine and family practice physicians as well as specialists such as infectious disease physicians, gastroenterologists, or hepatologists.

Combination therapy with pegylated interferon and ribavirin is the treatment of choice, resulting in sustained virologic response (defined as undetectable HCV RNA in the patient's blood 24 weeks after the end of treatment) rates of 40%–80% (up to 50% for patients infected with genotype 1, the most common genotype found in the United States, and up to 80% for patients infected with genotypes 2 or 3). Combination therapy using interferon and ribavirin is FDA-approved for use in children ages 3–17 years. Treatment success rates are now being improved with the addition of polymerase and protease inhibitors to standard pegylated interferon/ribavirin combination therapy.

At least six distinct HCV genotypes (genotypes 1–6) and more than 50 subtypes have been identified. Genotype 1 is the most common HCV genotype in the United States.

Yes. Because there are at least six known genotypes and more than 50 subtypes of HCV, genotype information is helpful in defining the epidemiology of hepatitis C and in making recommendations regarding treatment. Knowing the genotype can help predict the likelihood of treatment response and, in many cases, determine the duration of treatment.

• Patients with genotypes 2 and 3 are almost three times more likely than patients with genotype 1 to respond to therapy with alpha interferon or the combination of alpha interferon and ribavirin
• When using combination therapy, the recommended duration of treatment depends on the genotype. For patients with genotypes 2 and 3, a 24-week course of combination treatment is adequate, whereas for patients with genotype 1, a 48-week course is recommended.
  

Once the genotype is identified, it need not be tested again; genotypes do not change during the course of infection.

Superinfection is possible if risk behaviors (e.g., injection drug use) for HCV infection continue, but it is believed to be very uncommon.

A small percentage of persons with chronic HCV infection develop medical conditions due to hepatitis C that are not limited to the liver. These conditions are thought to be attributable to the body's immune response to HCV infection. Such conditions can include

• Diabetes mellitus, which occurs three times more frequently in HCV-infected persons
• Glomerulonephritis, a type of kidney disease caused by inflammation of the kidney
• Essential mixed cryoglobulinemia, a condition involving the presence of abnormal proteins in the blood
• Porphyria cutanea tarda, an abnormality in heme production that causes skin fragility and blistering
• Non-Hodgkins lymphoma, which might occur somewhat more frequently in HCV-infected persons
  

• The American Association for the Study of Liver Diseases: AASLD Practice Guideline: Diagnosis, Management, and Treatment of Hepatitis C.
• The National Institute of Diabetes and Digestive and Kidney Diseases: Chronic Hepatitis C Current Disease Management.
  

• Patients should be informed about the low but present risk for transmission with sex partners.
• Sharing personal items that might have blood on them, such as toothbrushes or razors, can pose a risk to others.
• Cuts and sores on the skin should be covered to keep from spreading infectious blood or secretions.
• Donating blood, organs, tissue, or semen can spread HCV to others.
• HCV is not spread by sneezing, hugging, holding hands, coughing, sharing eating utensils or drinking glasses, or through food or water.
• Patients may benefit from a joining support group.
  

• HCV-positive persons should be advised to avoid alcohol because it can accelerate cirrhosis and end-stage liver disease.
• Viral hepatitis patients should also check with a health professional before taking any new prescription pills, over-the counter drugs (such as non-aspirin pain relievers), or supplements, as these can potentially damage the liver.
  

CDC's recommendations for prevention and control of HCV infection specify that persons should not be excluded from work, school, play, child care, or other settings on the basis of their HCV infection status. There is no evidence of HCV transmission from food handlers, teachers, or other service providers in the absence of blood-to-blood contact.

After a needlestick or sharps exposure to HCV-positive blood, the risk of HCV infection is approximately 1.8% (range: 0%–10%).

Although a few cases of HCV transmission via blood splash to the eye have been reported, the risk for such transmission is expected to be very low. Avoiding occupational exposure to blood is the primary way to prevent transmission of bloodborne illnesses among healthcare personnel. All healthcare personnel should adhere to Standard Precautions.  Depending on the medical procedure involved, Standard Precautions may include the appropriate use of personal protective equipment (e.g., gloves, masks, and protective eyewear).

1. For the source, perform baseline testing for anti-HCV.
2. For the person exposed to an HCV-positive source, perform baseline and follow-up testing, including
   • baseline testing for anti-HCV and ALT activity AND
   • follow-up testing for anti-HCV (e.g., at 4–6 months) and ALT activity. If earlier diagnosis of HCV infection is desired, testing for HCV RNA may be performed at 4–6 weeks.
3. Confirmation by supplemental anti-HCV testing of all anti-HCV results reported as positive by enzyme immunoassay.
   

There are no CDC recommendations to restrict a healthcare worker who is infected with HCV. The risk of transmission from an infected healthcare worker to a patient appears to be very low. All healthcare personnel, including those who are HCV positive, should follow strict aseptic technique and Standard Precautions, including appropriate hand hygiene, use of protective barriers, and safe injection practices.

No. Since pregnant women have no greater risk of being infected with HCV than non-pregnant women and interventions to prevent mother-to-child transmission are lacking, routine anti-HCV testing of pregnant women is not recommended. Pregnant women should be tested for anti-HCV only if they have risk factors for HCV infection.

Approximately 4 of every 100 infants born to HCV-infected mothers become infected with the virus. Transmission occurs at the time of birth, and no prophylaxis is available to prevent it. The risk is increased by the presence of maternal HCV viremia at delivery and also is 2–3 times greater if the woman is coinfected with HIV. Most infants infected with HCV at birth have no symptoms and do well during childhood. More research is needed to find out the long-term effects of perinatal HCV infection.

No. There is no evidence that breastfeeding spreads HCV. However, HCV-positive mothers should consider abstaining from breastfeeding if their nipples are cracked or bleeding.

Children should be tested for anti-HCV no sooner than age 18 months because anti-HCV from the mother might last until this age. If diagnosis is desired before the child turns 18 months, testing for HCV RNA could be performed at or after the infant's first well-child visit at age 1–2 months. HCV RNA testing should then be repeated at a subsequent visit, independent of the initial HCV RNA test result.

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