An outbreak of hepatitis C virus infections among outpatients at a hematology/oncology clinic.

BACKGROUND

Approximately 2.7 million persons in the United States have chronic hepatitis C virus (HCV) infection. Health care-associated HCV transmission can occur if aseptic technique is not followed. The authors suspected a health care-associated HCV outbreak after the report of 4 HCV infections among patients at the same hematology/oncology clinic.

OBJECTIVE

To determine the extent and mechanism of HCV transmission among clinic patients.

DESIGN

Epidemiologic analysis through a cohort study.

SETTING

Hematology/oncology clinic in eastern Nebraska.

PARTICIPANTS

Patients who visited the clinic from March 2000 through December 2001.

MEASUREMENTS: HCV infection status, relevant medical history, and clinic-associated exposures. Bivariate analysis and logistic regression were used to identify risk factors for HCV infection.

RESULTS

Of 613 clinic patients contacted, 494 (81%) underwent HCV testing. The authors documented infection in 99 patients who lacked previous evidence of HCV infection; all had begun treatment at the clinic before July 2001. Hepatitis C virus genotype 3a was present in all 95 genotyped samples and presumably originated from a patient with chronic hepatitis C who began treatment in March 2000. Infection with HCV was statistically significantly associated with receipt of saline flushes (P < 0.001). Shared saline bags were probably contaminated when syringes used to draw blood from venous catheters were reused to withdraw saline solution. The clinic corrected this procedure in July 2001.

LIMITATION: The delay between outbreak and investigation (>1 year) may have contributed to an underestimate of cases.

CONCLUSIONS

This large health care-associated HCV outbreak was related to shared saline bags contaminated through syringe reuse. Effective infection-control programs are needed to ensure high standards of care in outpatient care facilities, such as hematology/oncology clinics.