Health Care-Associated Hepatitis C Virus Infections Attributed to Narcotic Diversion

Background: Three cases of genetically related hepatitis C virus (HCV) infection that were unattributable to infection control breaches were identified at a health care facility. Objective: To investigate HCV transmission from an HCV-infected health care worker to patients through drug diversion. Design: Cluster and look-back investigations. Setting: Acute care hospital and affiliated multispecialty clinic. Patients: Inpatients and outpatients during the period of HCV transmission. Measurements: Employee work and narcotic dispensing records, blood testing for HCV antibody and RNA, and sequencing of the NS5B gene and the hypervariable region 1 of the E2 gene. Results: 21 employees were recorded as being at work or as retrieving a narcotic from an automated dispensing cabinet in an area where a narcotic was administered to each of the 3 case patients; all employees provided blood samples for HCV testing. One employee was infected with HCV that had more than 95% NS5B sequence homology with the HCV strains of the 3 case patients. Quasi-species analysis showed close genetic relatedness with variants from each of the case patients and more than 97.9% nucleotide identity. The employee acknowledged parenteral opiate diversion. An investigation identified 6132 patients at risk for exposure to HCV because of the drug diversion. Of the 3929 living patients, 3444 (87.7%) were screened for infection. Two additional cases of genetically related HCV infection attributable to the employee were identified. Limitation: Of the living patients at risk for HCV exposure, 12.3% were not tested. Conclusion: Five cases of HCV infection occurring over 3 to 4 years were attributed to drug diversion by an HCV-infected health care worker. Studies of drug diversion and assessments of strategies to prevent narcotics tampering in all health care settings are needed.