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Low-dose vaccination against hepatitis B in children: one-year follow-up
Insights
Hepatitis B vaccination in children using H-B-Vax showed high antibody response rates. Booster doses effectively induced anamnestic responses in non-responders, indicating vaccine efficacy.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Hepatitis B virus (HBV) infection poses a significant public health risk.
- Assessing the immunogenicity and efficacy of plasma-derived hepatitis B vaccines in pediatric populations is crucial.
Purpose of the Study:
- To evaluate the immunogenicity of a plasma-derived hepatitis B vaccine (H-B-Vax) in children.
- To assess seroconversion rates, antibody titers, and the response to booster doses.
Main Methods:
- 643 HBV-marker-negative children received three 2-microgram doses of H-B-Vax at monthly intervals.
- Antibody to hepatitis B surface antigen (anti-HBs) levels were measured by RIA and EIA 12 months post-vaccination.
- A booster dose was administered to non-responders, and responses were analyzed.
Main Results:
- 89% (RIA) and 83% (EIA) seroconversion rates for anti-HBs were observed 12 months after vaccination.
- Younger children (1-4 years) showed significantly higher seroconversion rates and anti-HBs titers.
- 17 out of 18 non-responders developed anti-HBs after a booster dose, with 12 showing an anamnestic response.
Conclusions:
- The plasma-derived hepatitis B vaccine (H-B-Vax) is immunogenic in children, with higher response rates in younger age groups.
- Booster doses are effective in inducing anamnestic responses in children who did not initially seroconvert.
- The study provides evidence for the vaccine's efficacy in preventing hepatitis B infection in a pediatric cohort.
Abstract:
Six hundred forty-three children, negative for markers of hepatitis B virus (HBV) infections, were given three X 2-micrograms doses of Merck, Sharp and Dohme (MSD) plasma derived hepatitis B vaccine (H-B-Vax) at monthly intervals. Twelve months after the first dose of vaccine, antibody to hepatitis B surface antigen (anti-HBs) was detected in 89% of children by radioimmunoassay (RIA) and in 83% by enzyme immunoassay (EIA). Seroconversion rates and anti-HBs titres were significantly greater in 1-4-year-olds than in older children (p less than 0.01). Eighteen children with no anti-HBs or other markers of HBV at this time were given 10 micrograms of vaccine and tested one month later. Seventeen developed anti-HBs, 12 at levels consistent with an anamnestic response. Forty-nine HBV-marker-negative children seroconverted for antibody to hepatitis B core antigen (anti-HBc) in the 8-month period before or the 12-month period following vaccination. Forty-six of these children were positive for anti-HBs, and one has been confirmed as a chronic carrier of hepatitis B surface antigen (HBsAg). Three cases of clinical hepatitis B in children have been seen in the community since the vaccination programme began. Two of these were amongst the estimated 5% of children who were not vaccinated. The third was in a vaccinee and occurred 4 1/2 months after the last dose of vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)