A serological and molecular study of hepatitis B virus (HBV) infection was carried out in dialysis units in Central Brazil. Between 1995 and 1999, serum samples from all HBsAg-positive hemodialysis patients (n = 43) were tested for HBeAg/anti-HBe and subtyping by monoclonal ELISA. HBV DNA was detected by PCR and positive samples were genotyped by restriction fragment polymorphism pattern (RFLP) methodology. TheHBsAg prevalence declined in this population during the survey period (12-5.8%). HBeAg and anti-HBe were detected in 23 (53.5%) and 18 (41.9%) sera, respectively. Thirty-six samples could be HBsAg subtyped: 21 were subtype ayw(3), 14 belonged to adw(2) and one was identified as adw(4). HBV DNA was present in 30 serum samples. Of these, 20 (66.7%) were genotype D, 9 (30%) genotype A, and 1 (3.3%) genotype F. In addition, the RFLP pattern could be determined in samples from 18/20 genotype D patients: D3 (10 strains), D7 (7 strains) and D4 (1 strain); from 8/9 genotype A patients: A1 (6 strains) and A3 (2 strains); and from the patient infected with genotype F: F1. Patterns D3 and D7 were associated closely with HBV infection in the two largest hemodialysis units studied. These findings confirm the value of the RFLP method as an effective molecular epidemiological tool for elucidating HBV transmission in hemodialysis units.

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Hepatitis B vaccine is the most effective strategy for preventing the transmission of hepatitis B virus (HBV) in haemodialysis centers. Nevertheless, lower vaccine responses have been reported in haemodialysis patients as compared with healthy subjects. This study examines the response to Euvax-B in Brazilian haemodialysis patients and staff. A total of 102 eligible patients (n = 42) and staff members (n = 60) consented to be studied. Patients were immunized intramuscularly with four doses of 40 microg of Euvax-B vaccine at 0, 1, 2 and 6 months. In staff members, the vaccine was administered in three doses of 20 microg at 0, 1, and 6 months. Post-vaccine samples were taken from all subjects I month after each dose. The vaccine response was determined by measuring antibody to the hepatitis B surface antigen (anti-HBs) levels using ELISA. Subjects with anti-HBs titres equal to or higher than 10 UI/L were considered immune protected. Of the haemodialysis patients who received four doses of hepatitis B vaccine, 89.5% responded to Euvax-B vaccine. The geometric mean of anti-HBs titres was 322.8 IU/L (95% CI: 317.7-328). Among staff members, 93.3% reached anti-HBs protective titres after the third vaccine dose. The geometric mean of anti-HBs titres was 2,209 IU/L (Cl: 2,198-2,219). Age, male gender and body mass index were not associated with vaccine response in either group. This study showed a good immunogenicity response to Euvax-B in haemodialysis patients and staff.

A survey was conducted in the hemodialysis population of the state of Tocantins, Brazil, aiming