We performed a prospective study in a cohort of repeat To assess the incidence and source of community-acblood donors to estimate the risk of acquiring HCV infection quired hepatitis C virus (HCV) infection among subjects among individuals without parenteral exposure, and to invesat low risk for blood-borne diseases, we prospectively tigate the possible cause of infection. studied a cohort of 16,515 repeat blood donors over a mean follow-up time of 36 months. Second-and third-
PATIENTS AND METHODS generation methods were used for hepatitis C virus antibody (anti-HCV) testing. HCV RNA was determined in
A cohort of 18,109 anti-HCV-negative blood donors, candidates the serum of anti-HCV-positive donors by reverse-tranfor a second or subsequent donation, was enrolled between May 1991 scription polymerase chain reaction. Liver biopsy was and April 1992 in a longitudinal prospective study. Of this cohort, 16,515 subjects came to our center for further donations and were performed in the viremic subjects. Risk factors for HCV followed up for an average of 36 months (range, 3-52 months). The infection were identified by a psychosocial questionmedian interval between donations was 202 days. The male/female naire in the whole cohort. During follow-up, 5 donors ratio was 7:3, the median age was 32 years (range, 18-65 years). A became infected with HCV. The incidence was 1 per psychosocial questionnaire, based on 47 direct and indirect ques- 10,000 person-years (95% confidence interval, 0.3-2.4 per tions, was routinely administered to blood donors. 16 Questions re- 10,000). During the 6 months before seroconversion, four garded: 1) demographic information; 2) cigarette smoking and alcohol subjects (80%) underwent medical or surgical percutaneconsumption; 3) drug use, with reference to type, frequency, and time ous procedures, compared with 26.5% in the entire donor of last assumption; 4) sexual history; 5) history of hepatitis; and 6) cohort (difference between frequencies, 53.5%; CI: 18.9other risk factors for blood-borne infection (blood transfusion, tat- tooing, nosocomial exposure). At each donation, the clinical data