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Mass vaccination against hepatitis B in preschool children: immunogenicity after three reduced doses
Insights
This study found that a reduced dose of the MSD H-B Vax vaccine is highly effective in four-year-old children. The hepatitis B vaccine (H-B Vax) demonstrated a high seroconversion rate, indicating strong immunogenicity.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Hepatitis B virus (HBV) infection poses a significant public health risk.
- Effective vaccination strategies are crucial for preventing HBV transmission in pediatric populations.
- Assessing the immunogenicity of reduced vaccine doses can optimize public health interventions.
Purpose of the Study:
- To evaluate the immunizing effect of three reduced doses of Merck Sharp and Dohme (MSD) H-B Vax plasma-derived vaccine.
- To determine the seroconversion rates and antibody levels in four-year-old children receiving the vaccine.
- To assess the vaccine's immunogenicity across different geographical centers.
Main Methods:
- A cohort of 1225 four-year-old children received three 2 microgram doses of MSD H-B Vax intramuscularly at monthly intervals.
- Children with evidence of prior or current HBV infection were excluded from the primary analysis.
- Antibody to hepatitis B surface antigen (anti-HBs) was measured using enzyme immunoassay (EIA), with radioimmunoassay (RIA) used for quantitation in a subset of samples.
Main Results:
- Out of 1207 eligible children, 1186 (98.3%) achieved seroconversion (developed anti-HBs).
- Radioimmunoassay (RIA) confirmed positive anti-HBs in all 96 randomly selected sera, with a geometric mean titre of 1013.
- Seroconversion rates were consistently high nationwide, with 19 out of 39 centers achieving 100% seroconversion and no center below 92%.
Conclusions:
- Three reduced doses (2 micrograms each) of MSD H-B Vax plasma-derived vaccine administered monthly are highly immunogenic in four-year-old children.
- The vaccine demonstrates excellent efficacy and consistent performance across diverse geographical locations.
- This vaccination schedule represents a potentially effective strategy for hepatitis B prevention in pediatric populations.
Abstract:
The immunising effect of three reduced doses of Merck Sharp and Dohme (MSD) H-B Vax plasma derived vaccine delivered at monthly intervals was evaluated in 1225 four year old children. Eighteen children had evidence of previous or current infection with HBV. Of the remaining 1207 children, 1186 (98.3%) had antibody to hepatitis B surface antigen (anti-HBs) when tested by enzyme immunoassay (EIA). Levels of anti-HBs in 96 randomly selected sera were independently quantitated by radioimmunoassay (RIA) and all were positive for anti-HBs, with a geometric mean titre of 1013. There was no significant difference in seroconversion or anti-HBs levels between the groups of children nationwide. In 19 of the 39 centres, seroconversion was 100%. No centre had less than 92% seroconversion. This study confirms that three 2 microgram doses of MSD H-B Vax plasma derived vaccine given intramuscularly (IM) at monthly intervals are highly immunogenic in this paediatric population.