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[Evaluation of the effectiveness nine years after primary immunization with local produced plasma-derived hepatitis B
Insights
Hepatitis B vaccine remains effective nine years after initial immunization, showing sustained protection against infection. No booster dose is currently needed for vaccinated children, indicating long-term immunity.
Area of Science:
- Immunology
- Vaccinology
- Public Health
Background:
- Hepatitis B remains a significant global health concern.
- Long-term effectiveness of childhood hepatitis B vaccination is crucial for disease control.
Purpose of the Study:
- To evaluate the sustained effectiveness of a plasma-derived hepatitis B vaccine nine years post-primary immunization.
- To assess antibody persistence and protection rates against hepatitis B virus (HBV) infection in children.
Main Methods:
- A randomized, double-blind, placebo-controlled trial involving children immunized nine years prior.
- Monitoring of hepatitis B surface antigen (HBsAg), anti-HBc, and anti-HBs antibody levels.
- Analysis of factors influencing antibody decline and HBV infection occurrence.
Main Results:
- Nine years after immunization, vaccine recipients showed significantly higher anti-HBs positive rates and geometric mean titers (GMT) compared to placebo controls.
- Antibody titers in vaccinees were lower than at the 6-year follow-up but remained protective.
- The vaccine demonstrated high protection rates against HBV infection (81.4%) and HBsAg seroconversion (84.6%) at nine years.
Conclusions:
- The hepatitis B vaccine provides sustained protection for at least nine years after primary immunization.
- Current data suggest no immediate need for a booster dose in this cohort.
- Early antibody response post-immunization is a key factor in long-term antibody persistence.
Objective:
To observe the effectiveness of hepatitis B vaccine nine years after primary immunization.
Methods:
A randomized, controlled and double-blinded trial was designed with 126 children primarily immunized with local produced plasma-derived hepatitis B vaccine nine years ago and 135 placebo-control children aged five to nine years. All the children were followed-up, their blood samples collected and their disease occurrence examined. Their hepatitis B surface antigen (HBsAg), antibody against hepatitis B core antigen (anti-HBc) and antibody against hepatitis B surface antigen (anti-HBs) were tested. Causes of lowering in their antibodies were analyzed with multivariate methods.
Results:
During the nine-year follow-up, 4% to 19% of the study subjects dropped out. In the ninth year after immunization (T108), anti-HBs positive rate in the vaccinees and their geometric mean titer (GMT) (65.3% and 5.47, respectively) were still significantly higher than those in the placebo-controls (28.3% and 1.46, respectively), but significantly lower than those in the 6th year after immunization (T72). Multivariate analysis for the causes of lowering in the antibody during the 4th, 6th and 9th year after immunization showed that antibody titer in the vaccines first year after immunization (T12) was a crucial factor for the persistence of the antibody, and natural booster might also played a certain role in it. In the T108, one clinical case of hepatitis B occurred in the placebo control group, but no cases in the vaccinees found, with a protection rate of 81.4% from HBV infection and 84.6% from HBsAg positive-coversion, similar to those in the T72.
Conclusion:
The effectiveness of HB vaccine still existed nine years after primary immunization, and no booster dose was needed so far.