ROUTES OF INFECTION, VIREMIA, AND LIVER-DISEASE IN BLOOD-DONORS FOUNDTO HAVE HEPATITIS-C VIRUS-INFECTION

Background. For many people infected with the hepatitis C virus (HCV), the route of exposure, risk of transmission, and severity of associat ed liver disease are unknown. We studied these variables in people who donated blood voluntarily. Methods. Blood donors who tested positive for HCV antibodies on enzyme immunoassay were classified according to whether the results of a confirmatory second-generation recombinant im munoblot assay (RIBA) for HCV were positive, negative, or indeterminat e. The evaluations also included an assessment of risk factors, a phys ical examination, serial determinations of alanine aminotransferase le vels and HCV serologic assays, a polymerase-chain-reaction assay for H CV RNA, testing of sexual contacts and family members, and liver biops ies in some participants who were HCV-positive by RIBA. Results. A tot al of 481 donors were studied, among whom 248 were positive for HCV by RIBA, 102 had indeterminate results, and 131 were HCV-negative. In a logistic-regression analysis, significant risk factors for HCV infecti on among the HCV-positive participants were a history of blood transfu sion in 66 (27 percent; P<0.001 for the comparison with RIBA-negative donors), intranasal cocaine use in 169 (68 percent, P<0.001), intraven ous drug use in 103 (42 percent, P=0.001), sexual promiscuity in 132 ( 53 percent, P= 0.002), and ear piercing among men (P<0.05). Nine of 85 sexual partners of HCV-positive donors were anti-HCV-positive; 8 had used intravenous drugs or received transfusions. HCV RNA was found in 213 HCV-positive donors (86 percent), 3 who had indeterminate results by RIBA (2 of these 3 tested positive with a more specific, third-gene ration RIBA), and none who were HCV-negative. Of the HCV-positive dono rs, 69 percent had biochemical evidence of chronic liver disease; amon g 77 donors positive for HCV by RIBA who underwent liver biopsy, 5 had severe chronic hepatitis or cirrhosis, 66 had mild-to-moderate chroni c hepatitis, and 6 had no evidence of hepatitis. Conclusions. Among vo lunteer blood donors, prior blood transfusion, intranasal cocaine use, intravenous drug use, sexual promiscuity, and ear piercing in men are risk factors for HCV infection. The high frequency of intravenous dru g use was unexpected, because these donors had denied such use when qu estioned directly at the time of their blood donations. (C) 1996, Mass achusetts Medical Society.