Among volunteer 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 drug use was unexpected, because these donors had denied such use when questioned directly at the time of their blood donations.

No abstract

The precore-core gene of hepatitis B virus (HBV) was directly sequenced from serum samples of 42 patients with chronic B hepatitis (19 hepatitis B e antigen [HBeAg]+ and 23 anti-HBE+). Viral genotypes were determined by comparison with 11 reference sequences and by restriction analysis. Genotype A was identified in 16 cases, genotype D in 24 cases, and other genotypes in 2 cases. Precore mutations, mainly M1 (stop at codon 28), were differently distributed among the viral genotypes: 3 cases (18.8%) with genotype A and 18 cases (75%) with genotype D. In sequences with precore mutants, the encapsidation signal was more stable (negative stabilization energy) than in sequences without precore mutants. In genotype A, the M1 mutation coexisted with a second mutation (C-->T at position 1858 in codon 15), and both mutations were paired in the secondary structure of the RNA encapsidation signal, which justified the rare presence of precore mutants in this genotype. The analysis showed different distribution of mutations depending on the viral genotype; patients with genotype D were more likely to have persistent HBV infection by selection of precore mutants. Multiple amino acid substitutions were detected in the core region, mainly in two subsequences that have been previously described as epitopes (flanked by codons 11 to 27 and 74 to 83); the presence of these mutations was significantly related to the presence of precore variants which abolished the expression of HBeAg.(ABSTRACT TRUNCATED AT 250 WORDS)

About 90 percent of blood donors with antibody to HCV have infectious virus in their blood. The screening of blood donors for anti-HCV antibody should prevent about half the cases of transfusion-associated hepatitis, but the donors with infectious virus who are anti-HCV-negative may remain seronegative for prolonged periods.

Although the efficacy of hepatitis B vaccines in patients under chronic hemodialysis treatment has been well documented, the persistence of immunity in this population remains largely unknown. In this study we have followed 60 hemodiaysis patients up to 3 years after primary hepatitis B vaccination (four doses of recombinant hepatitis B vaccine; Engerix B, 20 mg/dose) to evaluate the persistence of immunity (as indicated by serum levels of antibody to hepatitis B surface antigen – anti-HBs – higher than or equal to 10 mlU/ml). Four-ty-four (73%) patients developed anti-HBs levels above 10 mlU/ml after vaccination; the remaining 16 (27%) vaccinees were considered nonresponders and were given a booster dose that again failed to elicit an immunoresponse. After 3 years of follow-up, 18 out of 44 (41 %) responders had no detectable anti-HBs levels in the serum (antibody loss occurring within 8 and 12 months in 3 cases, within 1 and 2 years in 13, and within 2 and 3 years in 2 other cases). When compared with the responders that lost their antibodies during the follow-up period, those who remained immunoreactive 3 years after vaccination was initiated were younger and had higher anti-HBs levels at 8 months of follow-up. Two hepatitis B virus infections were detected among nonresponders during the follow-up period. Based on these data, we conclude that patients undergoing chronic hemodialysis therapy not only have lower response rates to hepatitis B vaccination than healthy adults, but also that these are frequently transient. We then recommend for this population (1) anti-HBs testing soon after vaccination and (in case of response) every 6 months thereafter and (2) to give a booster dose to primary responders whenever their antibody levels decrease below 10 mlU/ml.