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.