Imunogenicidade da vacina brasileira contra hepatite B em adultos

Abstract

OBJECTIVE:To evaluate the immunogenicity and safety of a novel hepatitis B vaccine, after increasing antigen concentration to 25 μg, in comparison to the reference vaccine. METHODS:Single-blinded randomized trial comparing VrHB-IB (Instituto Butantan) and the reference vaccine (Engerix B®, Glaxo Smith Kline). Volunteers aged 31 to 40 years were randomized to either experimental (n=216) or control (n=203) groups, and were given three doses of vaccine. The fi rst dose was administered upon recruitment, and the second and third doses 30 and 180 days later, respectively, between 2004 and 2005. Blood samples were collected for analysis before randomization and after the second and third doses. Active search for adverse effects was perforned in the fi rst fi ve days after vaccination. Differences were evaluated using chi-square and Fisher's exact tests, with a 5% signifi cance level. RESULTS:No severe adverse effects were observed. Seroprotection was confi rmed in 98.6% (213/216) of volunteers in the experimental group and 95.6% (194/203) of those in the control group. Geometric mean titers were 12,557 and 11,673, respectively. CONCLUSIONS:The Brazilian vaccine was considered to be equivalent to the reference vaccine and its use is recommended for adults.

Prevalence of hepatitis B and C seropositivity in pregnant women

“…As years go by and people age, the vaccine response decreases, for instance, from 90% in adolescents and young adults, the vaccine response falls to 70% in people aged 50-59 years. In addition, there are other factors influencing the immunogenicity of the vaccine such as smoking, obesity, diabetes mellitus and HIV infection (6) . Studies have found that immunization of the mother against hepatitis B during pregnancy is safe and that the primary infant immunization with a recombinant vaccine confers long-term protection against clinical disease and chronic infection (7) .…”

Low Immunogenicity of Recombinant Hepatitis B Vaccine Derived from Hansenula polymorpha in Adults Aged Over 40 Years

“…A clinical trial comparing the immunogenicity of VrHB-B with Engerix-B in patients in this age group found that the vaccine produced in Brazil at the current concentration is equivalent to the gold standard. 6 The aim of our study was to evaluate the immunogenicity of VrHB-IB vaccination in rural settlers in central Brazil. Rural settlers who were susceptible to HBV comprised the vaccination group, and most of them were > 40 years of age.…”

“…13 The concentration of VrHB-IB is greater than recombinant HBsAg to the gold standard, Engerix-B. 6,14,15 According to Moraes and others, 6 with an HBsAg concentration of 25 μg/mL, the immunogenicity of the vaccine produced in Brazil for adults 31-40 years of age is equivalent to the gold standard, for which 98.6% of the vaccinees developed protective titers. In fact, in subjects < 40 years of age, the vaccine response was equivalent to that reported by other authors using vaccines expressed in S. cerevisiae (Engerix-B) 16 and H. polymorpha (GeneVac B).…”

“…However, our findings suggest that the immunogenicity of the Brazilian recombinant vaccine is even lower in individuals > 40 years of age compared with the gold-standard vaccine and others. 6,18 The greatest discrepancy in protection rates was found between the two vaccines that are expressed in H. polymorpha, and which also use the same adsorbent (aluminum hydroxide). 6,18 Therefore, it seems likely that factors such as storage, transport, and packaging may influence the effectiveness of the Brazilian vaccine.…”

“…6,18 The greatest discrepancy in protection rates was found between the two vaccines that are expressed in H. polymorpha, and which also use the same adsorbent (aluminum hydroxide). 6,18 Therefore, it seems likely that factors such as storage, transport, and packaging may influence the effectiveness of the Brazilian vaccine. However, all these factors were thoroughly checked during the developmental stages of this investigation, according to Brazilian recommendations.…”