Background and objective: In August 2002, the Oklahoma State Department of Health received a report of six patients with unexplained hepatitis C virus (HCV) infection treated in the same pain remediation clinic. We investigated the outbreak's extent and etiology.
Design, setting, and participants: We conducted a retrospective cohort study of clinic patients, including a serologic survey, interviews of infected patients, and reviews of medical records and staff infection control practices. Patients received outpatient pain remediation treatments one afternoon a week in a clinic within a hospital. Cases were defined as HCV or hepatitis B virus (HBV) infections among patients who reported no prior diagnosis or risk factors for disease or reported previous risk factors but had evidence of acute infection.
Results: Of 908 patients, 795 (87.6%) were tested, and 71 HCV-infected patients (8.9%) and 31 HBV-infected patients (3.9%) met the case definition. Multiple HCV genotypes were identified. Significantly higher HCV infection rates were found among individuals treated after an HCV-infected patient during the same visit (adjusted odds ratio [AOR], 6.2; 95% confidence interval [CI95], 2.4-15.8); a similar association was observed for HBV (AOR, 2.9; CI95, 1.3-6.5). Review of staff practices revealed the nurse anesthetist had been using the same syringe-needle to sequentially administer sedation medications to every treated patient each clinic day.
Conclusions: Reuse of needles-syringes was the mechanism for patient-to-patient transmission of HCV and HBV in this large nosocomial outbreak. Further education and stricter oversight of infection control practices may prevent future outbreaks.