Clinical Guidelines for the Medical Management of Hepatitis C
C. Risk Assessment and Screening
Persons at increased risk for HCV infection should be screened for serum HCV antibody.
HCV testing should be available to any patient who requests it.
Approximately 90% of patients with HCV have identifiable risk factors for infection. Understanding the relative risk for HCV infection is helpful for patient selection for screening (see Table 1).
|Relative Risk Factors for Hepatitis C Transmission|
|High Risk||Injection drug use||Blood or blood product transfusion or transplantation prior to 1992|
|Moderate Risk||High-risk sexual activity*||Vertical transmission from mother to baby|
|Low risk||Occupational exposure||Sexual activity between long-term spouses/sexual partners|
|Very low/No risk||Casual contact||Household contact|
|*Sexual transmission of HCV is not clearly understood. However, certain high risk sexual behaviors have been associated with HCV transmission such as anal sex, sex with trauma, sex in the presence of a sexually transmitted disease (STD), and sex without a condom.|
HCV is transmitted primarily through percutaneous exposure to infected blood. At least two-thirds of the patients currently identified with CHC infection were infected through injection drug use.19 Transfusion of blood or blood products is also strongly associated with the transmission of HCV. Although transmission of HCV by transfusion has declined dramatically in the U.S. following the introduction of more sensitive serological tests for HCV in 1992, some patients transfused before adequate screening was available are still being identified.19
The sexual transmission of HCV is not clearly understood. HCV is transmitted uncommonly between long-term spouses/sexual partners, with an average prevalence of 1.5%.19 Men who have sex with men (who do not engage in IDU) do not appear to be at substantially increased risk compared to controls.21 However, hepatitis C is more prevalent among those with multiple sex partners, a history of STDs, and/or failure to use a condom.19,22-24 In contrast, transmission via non-sexual household contact is rare in the U.S. and there is no evidence to suggest that HCV is transmitted by casual contact such as hand shaking, kissing, or sharing eating utensils.19,25 HIV and HCV share similar modes of transmission. The overall frequency of those with HIV being co-infected with HCV ranges from 16% to 30%, depending on the population studied.26,27 The overall rate of co-infection in those with HIV living New York City, is estimated to be 40%, with much higher rates among those with IDU as a risk factor for HIV.
Overall, the vertical transmission rate is approximately 5% (3-7% when the mother is only infected with HCV), and is not influenced by the method of delivery.28 The transmission rate of HCV is higher when the mother has a higher HCV RNA and when the mother is also co-infected with HIV.29 It is important to note that HCV antibodies may be transmitted passively from mother to baby. Thus, many children born to HCV-infected mothers will have passive antibody that may persist up to 18 months following delivery, but will not become infected with HCV. Therefore, testing for HCV antibody may be deferred until after 18 months of age. If there is a need for earlier diagnosis, HCV RNA may be measured at one to two months of age, at the time of the child's first well-child visit.30,31 Breast-feeding does not appear to be a significant risk factor, and should not be discouraged unless the nipples are cracked or bleeding.30
Transmission of HCV from patients to healthcare workers has been reported but is uncommon and the prevalence of hepatitis C in healthcare workers is similar to the general population.19,32 Seroconversion following accidental needle puncture is also uncommon and appears to be approximately 2% with a range of 0-7%.19,33 The exposure of mucous membranes or intact skin to infected blood does not appear to be a factor for transmission of HCV. Although rare, HCV transmission from infected healthcare workers to patients has been reported.34,35
While there is neither a standard approach nor definitive guidelines for management of occupational exposures or infected healthcare providers, this document provides some guidance for post-HCV exposure management (Section G). Although the NYSDOH does not address HCV specifically in policies for prevention of transmission of bloodborne pathogens, an existing policy statement does address prevention of exposure to HIV, hepatitis B virus (HBV), and other bloodborne pathogens, balanced against the rights of infected workers (Appendix B). HIV or HBV infection alone does not justify limiting a healthcare worker's professional duties.36 Limitations, if any, should be determined on a case-by-case basis after consideration of the factors that influence transmission risk, including inability or unwillingness to comply with infection control standards or functional impairment which interferes with job performance. The policy statement also requires the use of standard precautions and infection control training for licensed healthcare professionals every four years.
Up to 10% of those infected with HCV have no identified risk factor for acquisition of the virus. These patients may not recall past exposures, or may be reluctant to report risk factors. Intranasal cocaine use, tattoo application, religious scarification and body piercing have been associated with HCV infection.19 Finally, the guidelines panel's opinion is that HCV testing should be available to any patient who requests it. However, there is insufficient evidence to support routine screening in asymptomatic persons not at increased risk for HCV infection, according to the U.S. Preventive Services Task Force (USPSTF). In this group, the risks of screening and the subsequent diagnostic testing, if positive, may have risks outweighing the benefits.37