Immunogenicity and reactogenicity of two regimens of diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio and Haemophilus influenzae type b vaccines administered to infants primed at birth with hepatitis B vaccine.

An open, randomized study evaluated the immune response and safety of two different regimens of diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-Haemophilus influenzae type b (DTPa-HBV-IPV-Hib) immunization in infants primed at birth with hepatitis B vaccine. One-half of the 150 healthy, full-term infants received a DTPa HBV-IPV-Hib vaccine at 1 1/2, 3 and 5 months of age; the other received a DTPa-IPV-Hib vaccine at 1 1/2, 3 and 5 months of age with separate HBV vaccine at 1 and 5 months of age. Immune response was similar following the two regimens with 100% of the vaccinees seroprotected for HBV, diphtheria, tetanus, Hib and poliovirus types 2 and 3 diseases after the full vaccination course. One vaccinee in the DTPa HBV-HPV- Hib group failed to respond to the poliovirus type 1 antigen. Response to the three pertussis antigens ranged from 92-97% in the DTPa-IPV-Hib plus separate HBV group and 100% in the DTPa HBV-IPV-Hib group. The most frequently reported post-vaccination symptoms were irritability in the DTPa-IPV-Hib plus separate HBV group (49% of vaccinees) and fever, defined as axillary temperature > or =37.5 degrees C, in the DTPa HBV- IPV-Hib group (50% of vaccinees).

Comparison of the reactogenicity and immunogenicity of two different dose levels of hepatitis A vaccine in healthy children and adolescents.

An open study was performed to compare the reactogenicity and immunogenicity of an inactivated hepatitis A vaccine administered in two different doses and schedules to 460 healthy volunteers aged 3-18 years. Participants were randomized to two groups to receive either two doses of 720 ELISA Units (EL.U) inactivated hepatitis A per 0.5 ml dose according to a 0, 6-month schedule, or three doses of 360 EL.U according to a 0, 1, 6-month schedule. Transient local injection soreness was the most commonly reported symptom in almost half of both groups with no serious adverse events. One month after the primary course (one dose of 720 EL.U and two doses of 360 EL.U), 99% of 720 EL.U vaccinees had seroconverted, compared with 100% seroconversion in the 360 EL.U group. All vaccinees were seropositive after the booster dose of both vaccines with geometric mean anti-HAV titers of 2,359 and 2,967 mIU/ml in the 720 EL.U and 360 EL.U groups, respectively. The vaccine containing 720 EL.U of antigen per dose offers the advantage of convenience and acceptance of immunization afforded by a two-dose course of vaccination accompanied by a comparable antibody response with that achieved after three doses of vaccine containing 360 EL.U of antigen per dose.

Comparison study of combined DTPw-HB vaccines and separate administration of DTPw and HB vaccines in Thai children.

The safety, immunogenicity and tolerability of two different DTPw-HBV combination vaccines, containing 5 and 10 microg of HBsAg; were investigated in comparison with separate administration of DTPw and HBV (10 microg of HBsAg). A three dose primary vaccination course at 2, 4 and 6 months of age was followed by a booster dose at 18 months. All vaccines were safe and well tolerated. The DTPw-HBV combination vaccine containing 10 microg of HBsAg elicited significantly higher anti-HBs titres than the other two vaccines after the primary and booster vaccination course. All vaccines elicited a high response against the other components. Based on these results, DTPw-HBV (10 microg HBsAg) was the most effective vaccine at this schedule.

Hepatite A: uma doença possível de prevenção com vacina / Hepatitis A can be prevented with a vaccine

A doença causada pelo virus da hepatite A (VHA) costuma ser considerada como benigna, afetando principalmente os pré-escolares. Contudo, nesta revisäo se discutem os vários grupos da populaçäo em geral, nos quais a infecçäo pelo VHA pode apresentar consequências mais graves. Em consequência da alteraçäo epidemiológica verificada na América Latina, um número cada vez maior de adolescentes e adultos jovens se mantêm suscetíveis à infecçäo pelo VHA. A infecçäo por esse vírus, neste grupo etário, irá representar grave impacto no futuro, ausência prolongada ao trabalho e/ou escola e custos maiores para os sistemas locais de saúde. Em estudos recentes na Argentina e Chile, o VHA foi, também, o agente etiológico mais prevalente nos casos de insuficiência hepática fulminante em pré-escolares. A hepatite A aguda em pacientes com doença hepática crônica subjacente, especialmente hepatite C crônica, tem sido associada à insuficiência hepática grave ou fulminante. A prevençäo da hepatite A através da vacinaçäo parece ser o meio mais potente de se conter o VHA. As vacinas inativadas contra a hepatite A comprovaram ser seguras, altamente imunogênicas e indutoras de proteçäo duradoura contra infecçöes pelo VHA

The new DTPw-HBV-Hib combination vaccine can be used at the who schedule with a monovalent dose of hepatitis B vaccine at birth.

An open, randomized, clinical trial was conducted in order to assess the reactogenicity and immunogenicity of DTPw-HBV and Haemophilus influenzae type b (Hib) vaccines when given either as a mixed administration or as separate concomitant injections using the WHO schedule at 6, 10 and 14 weeks of age, following a dose of HBV at birth. There were no clinically relevant differences in the immune response to any component between the mixed and separate administrations. In fact the anti-tetanus GMTs were significantly higher (p=0.002) in mixed administration (3.9 IU/ml) compared with the separate administration (1.9 IU/ml). However although all subjects achieved anti-PRP titers > or = 0.15 microg/ml, higher anti-PRP GMTs were seen in the group receiving the separate administration. Importantly, the addition of Hib did not adversely alter the reactogenicity profile of DTPw-HBV. This report which demonstrates that this novel combination can be used in WHO recommended schedule.

Randomized, single-blind comparison of the immunogenicity and reactogenicity of 20 micrograms and 10 micrograms doses of hepatitis B vaccine in adolescents.

The study compares the effect of two different doses of a recombinant DNA hepatitis B vaccine (Engerix-B) administered to 320 healthy adolescents divided randomly into two equal groups, using the 0, 1 and 6 month's vaccination schedule. Initially the larger dose elicited protective levels of antibody in a greater proportion of subjects. The seroprotection rates were significantly higher at both months 1 (17.6% v/s 9.2%) and 2 (68.8% v/s 56.7%). The difference was especially relevant 6 months after the start of the vaccination schedule when a 92.4% seroprotection rate was obtained in the 20 micrograms dose group, whereas only 78.3% of subjects in the 10 micrograms dose group had protective antibody levels. Furthermore there were significant differences in anti-HBs geometric mean titers for seroconverters at months 6 (109 v/s 56mlU/ml) and 7 (4774 v/s 2705mlU/ml). However one month after the third vaccine administration, both doses produced similar high seroprotection rates (97.9% and 97.1%, respectively). The difference in the generally mild overall reactogenicity for the 2 dose levels was not remarkable although the higher dose produced more local symptoms. The conclusion from the study was that the 10 micrograms dose produces a very good antibody response in adolescents, provided the full vaccination course of three doses, according to a 0, 1 and 6 month's schedule, is administered. However, the 20 micrograms dose should be used if compliance to the full course is in doubt since a 92.4% seroprotection rate can be obtained with 2 injections compared to only 78.3% with the 10 micrograms dose.