title: A large nosocomial outbreak of hepatitis C virus infections at a hemodialysis center.
abstract: OBJECTIVE
  To identify modes of HCV transmission during an outbreak of HCV infection in a hemodialysis unit.
  
  
  METHODS
  An epidemiologic study, virologic analysis, assessment of infection control practices and procedures, and technical examination of products and dialysis machines.
  
  
  METHODS
  A private hemodialysis unit treating approximately 70 patients.
  
  
  METHODS
  Detection of HCV RNA by PCR was performed among patients receiving dialysis in 2001. Case-patients were patients who had a first positive result for HCV RNA between January 2001 and January 2002 and either acute hepatitis, a seroconversion for HCV antibodies, or a previous negative result. Three control-patients were randomly selected per case-patient.
  
  
  RESULTS
  Of the 61 patients treated in the unit in 2001 and not infected with HCV, 22 (36.1%) became case-patients with onset from May 2001 to January 2002 for an incidence density rate of 70 per 100 patient-years. Phylogenic analysis identified four distinct HCV groups and an index case-patient for each with a similar virus among patients already known to be infected. No multidose medication vials or material was shared between patients. Connection to a dialysis machine by a nurse who had connected an HCV-infected patient "just before" or "one patient before" increased the risk of HCV infection, whereas using the same dialysis machine after a patient infected with HCV did not. Understaffing, lack of training, and breaches in infection control were documented. Direct observation of practices revealed frequent flooding of blood into the double filter on the arterial pressure tubing set.
  
  
  CONCLUSIONS
  During this outbreak, HCV transmission was mainly patient to patient via healthcare workers' hands. However, transmission via dialysis machines because of possible contamination of internal components could not be excluded.
authors.affiliation: C. Clin Sud-Est, Centre Hospitalier Lyon Sud, Lyon, France. anne.savey@chu-lyon.fr
authors.forename: Anne
authors.initials: A
authors.lastname: Savey
authors.forename: Fernando
authors.initials: F
authors.lastname: Simon
authors.forename: Jacques
authors.initials: J
authors.lastname: Izopet
authors.forename: Agnès
authors.initials: A
authors.lastname: Lepoutre
authors.forename: Jacques
authors.initials: J
authors.lastname: Fabry
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Desenclos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003428:Cross Infection / Q000453:epidemiology*; D004196:Disease Outbreaks; D004866:Equipment Contamination; D005260:Female; D005602:France / Q000453:epidemiology; D006436:Hemodialysis Units, Hospital; D006526:Hepatitis C / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D017053:Infection Control / Q000458:organization & administration; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis
chemical_list: D012367:RNA, Viral