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Placebo-controlled efficacy study of hepatitis A vaccine in Valdivia, Chile
S Riedemann1, G Reinhardt, G G Frösner
1Institute of Microbiology, Universidad Austral de Chile, Valdivia.
Insights
This study demonstrated high efficacy for a hepatitis A vaccine in children, with over 95% seroconversion rates. The vaccine was well-tolerated, showing no serious side effects, supporting its use in pediatric populations.
Area of Science:
- * Virology
- * Immunology
- * Vaccinology
Background:
- * Hepatitis A virus (HAV) poses a significant public health concern.
- * Development of effective vaccines is crucial for preventing HAV infection.
Purpose of the Study:
- * To evaluate the efficacy and safety of a hepatitis A vaccine in children.
- * To compare the hepatitis A vaccine against a hepatitis B vaccine control.
Main Methods:
- * A placebo-controlled, double-blind study involving 260 healthy children aged 6-15 years.
- * Participants received either hepatitis A vaccine or hepatitis B vaccine at 0, 1, and 6 months.
- * Serological testing for anti-HAV, anti-HAV IgM, and transaminases conducted at multiple time points.
Main Results:
- * Hepatitis A vaccine (Group 1) achieved high seroconversion rates: 95.5% at month 1, 99.2% at month 2, and 100% by month 7.
- * Geometric mean anti-HAV concentrations showed a robust immune response.
- * Both vaccines were equally well-tolerated with no serious adverse events observed.
Conclusions:
- * The hepatitis A vaccine demonstrated excellent efficacy and safety in the studied pediatric population.
- * The findings support the use of this hepatitis A vaccine for preventing HAV infection in children.
Abstract:
A placebo-controlled, double-blind study on the efficacy of a hepatitis A vaccine (SmithKline Beecham Biologicals) was started in a region of Chile in September 1990, using hepatitis B vaccine as control. A total of 260 healthy children, 6-15 years of age, negative for antibody to hepatitis A virus (anti-HAV), antibody to HAV immunoglobulin M (IgM), hepatitis B surface antigen, and antibody to hepatitis B surface and core antigens by ELISA tests within 7 days before vaccination, were randomly assigned to two study groups: 128 children received the vaccine with a yellow label (group 1), and 132 children the vaccine with an orange label (group 2) at months 0, 1 and 6. Blood for serology and transaminase determination was drawn at months 1, 2, 6, 7 and 12. Both vaccines were tolerated equally well and no serious side effects were seen. In group 1 (presumed hepatitis A vaccine group), anti-HAV was detected (20% inhibition was used as the cut-off level) in 122 of 128 children (95.5%) tested at month 1, in 126 of 127 (99.2%) at month 2, in 126 of 127 (99.2%) at month 6 and in 126 of 126 (100%) at month 7. One anti-HAV seroconversion seen at month 1 was associated with presence of anti-HAV IgM and therefore probably represents HAV infection. Geometric mean anti-HAV concentration of the other children was 128, 342, 214 and 2301 mIU/ml at months 1, 2, 6 and 7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)