Literature Reviews
Mann KR, Davis GL. Hepatitis C virus infection among health care workers (questions and answers). JAMA 1996; 275:1,474-1,475.
Mann, a physician, poses a question that is answered by Davis, a hepatobiliary diseases doctor at the University of Florida College of Medicine in Gainesville. Mann asks whether job restrictions are appropriate for a 38-year-old circulating and surgical nurse who recently tested positive for antibody to hepatitis C virus. No evidence was found of active hepatitis C. Occupational exposure was identified as the only risk factor. Since her seroconversion was discovered, the nurse no longer has been permitted to circulate or scrub on surgery patients. Mann asks whether evidence exists to support those restrictions.
The reply suggests that first, because the nurse has normal aminotransferase levels, a supplemental test such as the confirmatory strip immunoblot assay should be performed. Positive results would confirm prior exposure but would not determine whether current infection exists. Documentation of HCV RNA in the serum by reverse transcription polymerase chain reaction testing is advised to support the presence of infection, but its absence would not eliminate the possibility of low-level viremia. For purposes of discussion, Davis assumes that the nurse is confirmed HCV-infected.
He points out that health care workers have an increased risk of acquiring HCV infection, with seroprevalence rates ranging from 0.6% to 4.5%. Increased prevalence of anti-HCV antibodies among HCWs results from exposure to infected patients’ blood; the higher the degree of exposure, the greater the risk. Risk magnitude is illustrated by serological surveys among emergency department patients, of whom 18% on average are HCV-infected. The proportion with HCV is higher in patients with histories of intravenous drug use (83%), blood transfusion (21%), or a male homosexual lifestyle (21%).
Needlestick injuries probably account for a large proportion of HCV infection among HCWs, Davis notes. The risk of acquiring HCV infection by this route could be as high as 10.3%, and in general is higher than the risk of acquiring hepatitis B or HIV infection by needlestick.
Unlike HBV, the risk of chronic hepatitis is more than 70% after acute HCV infections, and more than 20% of patients will progress to cirrhosis. Therefore, the risk of acquiring irreversible liver injury from an infected needlestick is 0.4% to 1.0% for HCV, compared with approximately 0.04% for HBV. Also, no evidence suggests that HCV transmission can be prevented by immune globulin, and it is not indicated for treatment of acute exposure.
Davis says HCV-infected HCWs are not likely to place patients at risk. No studies have prospectively screened patients of HCV-positive HCWs. Only one report suggests transmission occurred. In that study, six patients among a group of 525 transfusion recipients being monitored for post-transfusion hepatitis in Spain were found to have acquired HCV infection despite having received blood only from HCV-negative donors. All had undergone cardiac procedures by the same thoracic surgeon, who subsequently was found to be anti-HCV-positive and to have elevated levels of serum alanine aminotransferase and HCV RNA. Nucleotide sequencing analysis indicated that the surgeon and five of the six patients were infected with the same HCV genotype.
In summary, Davis states that although some evidence exists that the patients of HCV-positive HCWs are exposed to an increased infection risk, "considering the current universal use of appropriate precautions, the risk to . . . patients should be minimal."
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