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Posted on November 02, 2007

 

Hepatitis C virus (HCV) infection is the most common chronic bloodborne infection in the United States; approximately 2.7 million persons are chronically infected. Although HCV is not efficiently transmitted sexually, persons at risk for infection through injection-drug use might seek care in STD treatment facilities, HIV counseling and testing facilities, correctional facilities, drug treatment facilities, and other public health settings where STD and HIV prevention and control services are available.

Persons newly infected with HCV typically are either asymptomatic or have a mild clinical illness. HCV RNA can be detected in blood within 1–3 weeks after exposure. The average time from exposure to antibody to HCV (anti-HCV) seroconversion is 8–9 weeks, and anti-HCV can be detected in >97% of persons by 6 months after exposure. Chronic HCV infection develops in 60%–85% of HCV-infected persons; 60%–70% of chronically infected persons have evidence of active liver disease. The majority of infected persons might not be aware of their infection because they are not clinically ill. However, infected persons serve as a source of transmission to others and are at risk for CLD or other HCV-related chronic diseases for decades after infection.

HCV is most efficiently transmitted through large or repeated percutaneous exposure to infected blood (e.g., through transfusion of blood from unscreened donors or through use of injecting drugs), although less efficient, occupational, perinatal, and sexual exposures also can result in transmission of HCV.

The role of sexual activity in the transmission of HCV has been controversial. Case-control studies have reported an association between acquiring HCV infection and exposure to a sex contact with HCV infection or exposure to multiple sex partners. Surveillance data also indicate that 15%–20% of persons reported with acute HCV infection have a history of sexual exposure in the absence of other risk factors. Case reports of acute HCV infection among HIV-positive MSM who deny injecting-drug use have indicated that this occurrence is frequently associated with other STDs (e.g., syphilis). In contrast, a low prevalence (average: 1.5%) of HCV infection has been demonstrated in studies of long-term spouses of patients with chronic HCV infection who had no other risk factors for infection, and multiple published studies have demonstrated the prevalence of HCV infection among MSM who have not reported a history of injecting-drug use to be no higher than that of heterosexuals. Because sexual transmission of bloodborne viruses is more efficient among homosexual men compared with heterosexual men and women, the reason that HCV infection rates are not substantially higher among MSM compared with heterosexuals is unclear. Overall, these findings indicate that sexual transmission of HCV is possible but inefficient. Additional data are needed to determine whether sexual transmission of HCV might be increased in the context of HIV infection or other STDs.

  

Diagnosis and Treatment

 

Anti-HCV testing is recommended for routine screening of asymptomatic persons based on their risk for infection or based on a recognized exposure. For such persons, testing for HCV infection should include the use of an FDA-cleared test for antibody to HCV (i.e., immunoassay, EIA, or enhanced chemiluminescence assay and, if recommended, a supplemental antibody test).

Persons counseled and tested for HCV infection and determined to be anti-HCV positive should be evaluated (by referral or consultation, if appropriate) for presence of active infection, presence or development of CLD, and for possible treatment. Reverse transcriptase polymerase chain reaction to detect HCV RNA may be used to confirm the diagnosis of current HCV infection, and an elevated alanine aminotrans-ferase (ALT) level is biochemical evidence of CLD. Combination therapy with pegylated interferon and ribavirin is the treatment of choice for patients with chronic hepatitis C. Because of advances in the field of antiviral therapy for acute and chronic hepatitis C, clinicians should consult with specialists knowledgeable about management of hepatitis C infection.

  

Prevention

 

No vaccine for hepatitis C is available, and prophylaxis with immune globulin is not effective in preventing HCV infection after exposure. Reducing the burden of HCV infection and disease in the United States requires implementation of both primary and secondary prevention activities. Primary prevention reduces or eliminates HCV transmission; secondary prevention activities reduce liver and other chronic diseases in HCV-infected persons by identifying them and providing appropriate medical management and antiviral therapy, if appropriate.

Persons seeking care in STD clinics or other primary-care settings should be screened to identify those who should be offered HCV counseling and testing. In STD clinics and other settings that serve large numbers of persons at high risk for bloodborne infections (e.g., correctional settings), the major risk factor for which to screen for HCV infection is injection of illegal drugs. In addition, for clinical management issues, all persons with HIV infection should also be offered HCV counseling and testing. Other risk factors for which routine HCV testing is recommended include persons

  • who had a blood transfusion or solid organ transplant before July 1992,
  • who received clotting factor concentrates produced before 1987,
  • who have been on long-term dialysis, and
  • those with signs and symptoms of liver disease (e.g., abnormal ALT).

Persons who test positive for anti-HCV should be provided information regarding 1) how to protect their liver from further harm, 2) how to prevent transmission to others, and 3) the need for medical evaluation for CLD and possible treatment.

  • To protect their liver from further harm, HCV-positive persons should be advised to avoid alcohol and taking any new medicines (including OTC and herbals) without checking with their doctor.
  • To reduce the risk for transmission to others, HCV-positive persons should be advised to 1) not donate blood, body organs, other tissue, or semen; 2) not share any personal items that might have blood on them (e.g., toothbrushes and razors); and 3) cover cuts and sores on the skin to keep from spreading infectious blood or secretions. HCV-positive persons with one long-term, steady sex partner do not need to change their sexual practices. They should discuss the low but present risk for transmission with their partner and discuss the need for counseling and testing. HCV-positive women do not need to avoid pregnancy or breastfeeding.
  • HCV-positive persons should be evaluated (by referral or consultation, if appropriate) for presence of development of CLD, including assessment of liver function tests, assessment for severity of liver disease and possible treatment, and determination of the need for hepatitis A and B vaccination.

Persons who test negative for anti-HCV who had an exposure previously should be reassured that they are not infected.

Regardless of test results, persons who use or inject illegal drugs should be counseled to

  • stop using and injecting drugs;
  • enter and complete substance abuse treatment, including relapse prevention;
  • take the following steps to reduce personal and public health risks, if they continue to inject drugs:

    • never reuse or share syringes, water, or drug preparation equipment;
    • use only syringes obtained from a reliable source (e.g., pharmacies);
    • use a new, sterile syringe to prepare and inject drugs;
    • if possible, use sterile water to prepare drugs; otherwise, use clean water from a reliable source (e.g., fresh tap water);
    • use a new or disinfected container (“cooker”) and a new filter (“cotton”) to prepare drugs;
    • clean the injection site before injection with a new alcohol swab;
    • safely dispose of syringes after one use; and
    • get vaccinated for hepatitis A and B.

  

Postexposure Follow-Up

 

No PEP has been demonstrated to be effective against HCV. Testing to determine whether HCV infection has developed is recommended for health-care workers after percutaneous or permucosal exposures to HCV-positive blood and for children born to HCV-positive women.

 

Special Considerations

 

Pregnancy

 

Routine testing for HCV infection is not recommended for all pregnant women. Pregnant women with a known risk factor for HCV infection should be offered counseling and testing. Patients should be advised that approximately five of every 100 infants born to HCV-infected woman become infected. This infection occurs predominantly during or near delivery, and no treatment or delivery method is known to decrease this risk. The risk is increased by the presence of maternal HCV viremia at delivery and also is greater (2–3 times) if the woman is coinfected with HIV. Breastfeeding does not appear to transmit HCV, although HCV-positive mothers should consider abstaining from breastfeeding if their nipples are cracked or bleeding. Infants born to HCV-positive mothers should be tested for HCV infection and, if positive, evaluated for the presence of CLD.

HIV Infection

 

Because of the high prevalence of HIV/HCV coinfection and because of critical clinical management issues for coinfected persons, all HIV-infected persons should be tested for HCV. Because a small percentage of coinfected persons fail to acquire HCV antibodies, HCV RNA should be tested in HIV-positive persons with unexplained liver disease who are anti-HCV negative. The course of liver disease is more rapid in HIV/HCV coinfected persons, and the risk for cirrhosis is nearly twice that in persons with HCV infection alone. Treatment of HCV in coinfected persons might improve tolerance to highly active antiretroviral therapy (HAART) for HIV infection because of the increased risk for hepatotoxicity from HAART with HCV infection. However, anti-HCV treatment in coinfected persons is still investigational, and based on ongoing clinical trials, more data are needed to determine the best regimens.


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