Immunogenicity of a Hepatitis B Recombinant Vaccine Produced by Intituto Butantan among Children in Rio de Janeiro.
Recently, the Instituto Butantan (São Paulo, Brazil) produced the first Brazilian recombinant vaccine against hepatitis B (BUTANG-BUT). To enlarge the existing data, the GPNI/FNS/MS promoted a multi-center study, carried out in 5 localities and among different age strata. As part of this project, we investigated the immunogenicity of BUT among children aged 1-10 years from Educandário Lar de Frei Luiz, Rio de Janeiro, during the period 2001-2002. Children were immunized with 3 doses (10ug) of BUT (N=219) or Engerix B (?EB?, Glaxo SmithKline Biologicals, N=264), following the schedule 0, 1, 6 months. Blood samples were collected prior to the first (C0) and 28-100 days after the third doses (C1). Detection of HBV markers was performed using immunoassays (BioMerieux) (C0) and anti-HBc was retested in C1. Anti-HBs titer was determined using a paramagnetic-particle chemiluminescent immunoassay (Access Ab HBs II, Beckman-Coulter) and seroprotection was defined as anti-HBs amp;#8805;10mUI/ml. Equivalence between vaccines was defined as i) a difference not larger than 5% between seroprotection proportions (BUT? EB) and ii) GMT-BUT/GMT-EB ratio gt;0.67. Seroprotection was observed in 100.0% and 97.7% of children, with GMTs of 3.600 mUI/ml and 2761 mUI/ml for BUT and EB, respectively. The difference between seroprotection proportions was 2.3% and GMT ratio was 1.3. During the project we evaluated different commercially assays to assess HBV vaccine response. A total of 163 samples were further tested using a microparticle enzyme immunoassay (IMx AUSAB, Abbott Laboratories) and a method based in EIA (ETI-AB-AUK-3, Diasorin). The tests presented concordant results (plt;0.01). We analyzed in pairs ? Access/IMx, Access/Diasorin and IMx/Diasorin. The linear coefficients were 0.960, 0.913 and 0.943, respectively. The highest correlation was among Access/IMx. These results showed that both vaccines are equivalent and suitable for use among children and that commercial assays are suitable for vaccine response evaluation.
Advisor:Clara Fumiko Tachibana Yoshida
School:Faculdades Oswaldo Cruz
Source Type:Master's Thesis
Date of Publication:04/08/2006