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Very low dose hepatitis B vaccination in the newborn: anamnestic response to booster at four years
Insights
Infant hepatitis B vaccination with plasma-derived vaccine (PDV) primes for long-term immunity. A recombinant DNA (rDNA) booster vaccine effectively restores protective antibody levels years later.
Area of Science:
- Immunology
- Vaccinology
- Hepatology
Background:
- Hepatitis B virus (HBV) infection poses a significant global health risk.
- Infant vaccination is crucial for preventing chronic HBV infection.
- Long-term immunogenicity of early low-dose plasma-derived vaccines (PDV) requires evaluation.
Purpose of the Study:
- To assess the durability of immune response after low-dose PDV in infancy.
- To evaluate the efficacy of a recombinant DNA (rDNA) hepatitis B vaccine as a booster.
- To determine if immunological memory persists despite low antibody levels.
Main Methods:
- Follow-up study of 78 children vaccinated in infancy with low-dose PDV (1 or 2 microg).
- Measurement of anti-HBs antibody levels at approximately four years of age.
- Administration of a 2 microg dose of MSD rDNA hepatitis B vaccine as a booster and assessment of response.
Main Results:
- After primary low-dose PDV, anti-HBs levels fell below 10 mlU/ml in 38% (1 microg) and 17% (2 microg) of responders by age four.
- No children showed evidence of past HBV infection (anti-HBc positive).
- A 2 microg rDNA booster vaccine successfully restored anti-HBs levels above 10 mlU/ml in all subjects, with 90% exceeding 1,000 mlU/ml.
Conclusions:
- Infant response to hepatitis B vaccine establishes effective immunological memory lasting several years.
- Low anti-HBs antibody levels do not necessarily indicate loss of protection.
- The MSD 2 microg rDNA hepatitis B vaccine is an effective booster for individuals previously vaccinated with PDV.
Abstract:
Seventy-eight children who had received three very low doses (1 or 2 microg) of Merck, Sharp and Dohme (MSD) plasma-derived vaccine (PDV) in early infancy were followed to approximately four years of age. Of the 70 who had responded to the initial course of vaccine with measurable anti-HBs, levels had fallen to below 10 mlU/ml in 38% of subjects given 1 microg doses and in 17% of those who had been given 2 microg doses. None of the children were positive for anti-HBc. Two weeks after 2 microg dose of MSD recombinant DNA (rDNA) vaccine all subjects had more than 10 mlU/ml of anti-HBs, with 90% exceeding 1,000 mlU/ml. A response to hepatitis B vaccine in infancy is followed by an effective immunological memory for several years, even if anti-HBs falls to low levels. The rDNA hepatitis B vaccine (MSD) in 2 microg doses is an effective booster following a primary course of plasma derived vaccine.