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BACKGROUND: Hemodialysis patients are at increased risk for acquiring hepatitis C virus (HCV) infection. Through annual HCV antibody screening in December 2012, an outpatient hemodialysis center (Clinic A) identified five patients who seroconverted. Upon detection, health authorities were notified and an investigation launched. Monthly screening was implemented and after a sixth patient seroconverted in April 2013, the investigation was expanded to further identify and describe case-patients, characterize lapses in infection control (IC) and to prevent additional transmission.
METHODS: Case-patients were defined as antibody to HCV negative upon facility admission, but subsequently found positive by antibody or RNA. Exposure period for case-patients was three months to two weeks prior to first documented alanine aminotransferase level elevation preceding HCV seroconversion. Previously-infected patients included those HCV positive upon admission. HCV antibody screening was performed by the facility and followed by RNA confirmation. CDC conducted quasispecies analysis to determine HCV relatedness. The investigation included chart review from 2008–present, case-patient interviews, and IC observation. A chemiluminescent agent was used to identify blood contamination on environmental surfaces.
RESULTS: Clinic A dialyzed 66 patients three days a week, during three shifts. Chart review identified 18 case-patients with HCV seroconversion from 2008-2013, of which, four (22%) had documented symptoms. Information from twelve case-patient interviews revealed no risk factors or common healthcare exposure outside of Clinic A. Case-patients were often proximally located to previously-infected patients, either in the same treatment station on consecutive shifts or adjacent to each other in the same shift. Quasispecies analysis detected four distinct viral sequence clusters which included 11/13 case-patients and 4/10 previously-infected patients tested. Environmental sampling revealed human blood contamination on dialysis chairs and side tables. Observation detected multiple IC lapses, including aseptic technique breaches during site access and insufficient and rapid cleaning of hemodialysis stations, often while patients were still present. The medication preparation area had been moved into a dedicated room prior to our observations during which no significant injection safety breaches were identified.
CONCLUSIONS: A large HCV outbreak occurred in a hemodialysis clinic where suboptimal IC practices were identified. Allowing insufficient time between patients for adequate environmental cleaning contributed to IC lapses that may have led to HCV transmission. Prevention of HCV infection in hemodialysis facilities can be supported through bi-annual HCV screening of susceptible patients, routine IC auditing, and continued education. Health departments can contribute to prevention efforts through technical support in outbreak investigation and response and provision of educational materials.