Control of hepatitis B: evaluation of two different vaccinal schedules in newborns from HBsAg negative mothers
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C Belloni1, P Orsolini, M Martinetti
1Division of Neonatal Intensive Care, I.R.C.C.S. Policlinico S. Matteo, Pavia, Italy.
Insights
An accelerated hepatitis B vaccine schedule for infants demonstrated high protection rates, comparable to traditional schedules. This study highlights the effectiveness of early infant vaccination against hepatitis B virus (HBV).
Area of Science:
- Pediatric Immunology
- Vaccinology
- Hepatology
Background:
- Hepatitis B virus (HBV) infection poses a significant global health risk.
- Infant vaccination is crucial for preventing chronic HBV infection and its sequelae.
- Evaluating different immunization schedules optimizes vaccine efficacy and infant immune response.
Purpose of the Study:
- To compare the immunogenicity and efficacy of an accelerated versus a traditional HBV vaccination schedule in infants.
- To assess infant immune response, including antibody titers and responder status, to recombinant HBV vaccine (Engerix B).
- To investigate the potential influence of human leukocyte antigen (HLA) haplotypes on vaccine response.
Main Methods:
- 504 healthy infants were randomized into two groups: accelerated (vaccination at 4 days, 1 month, 3 months) and traditional (vaccination at 4 days, 1 month, 6 months).
- All infants received 10 micrograms of recombinant HBV vaccine.
- Serum antibody levels (HBsAb) were measured after the first and booster doses. Immunogenetic analysis of HLA haplotypes was performed on non-responders and hypo-responders.
Main Results:
- Both accelerated and traditional schedules induced high seroprotective antibody levels (>10 mIU/ml) in over 97% of infants after the booster dose.
- Non-response ( < 2 mIU/ml) was minimal (none in the accelerated group, 2 in the traditional group).
- Hypo-response (2.1–9.9 mIU/ml) occurred in 4 infants in each group. HLA haplotype analysis revealed associations with both hypo- and hyper-responsiveness.
Conclusions:
- An accelerated infant immunization schedule using recombinant HBV vaccine is highly effective and comparable to the traditional schedule in inducing protective immunity.
- Early infant vaccination starting at birth provides a high degree of protection against hepatitis B virus.
- While most infants respond well, immunogenetic factors like HLA haplotypes may play a role in vaccine response variability.
Abstract:
504 healthy infants, born to HBsAg negative mothers from May 1st to December 31st 1991, were randomly allocated to an accelerated (group A) or traditional (group B) immunization schedule. The group A infants were immunized at 4 days, 1 month and 3 months of life with 10 micrograms of recombinant HBV vaccine (Engerix B, SKF) while the group B infants were immunized at 4 days, 1 month and 6 months of life with the same dose of vaccine. One month after the first dose of vaccine, 9.2% of the infants in both groups had an HBsAb serum level > 10 mIU/ml. One month after the booster dose, at 4 months of life for group A and at 7 months for group B, 97.40% and 98.53% of the infants presented a serum level > 10 mIU/ml respectively. None in group A and only 2 patients in group B could be considered non-responders (serum concentration below 2 mIU/ml) and 4 infants in group A and 4 in group B were considered hypo-responders (serum level between 2.1 and 9.9 mIU/ml). Immunogenetic study performed on the 2 non-responders and 6 of the hypo-responders, revealed the presence in all but two of the HLA haplotypes, classically involved in the lack of hyporesponsiveness to foreign peptides, namely: HLA-DR7; DQ2, DR4; DQ3, DR15; DQ6 and DR3; DQ2. Surprisingly, 2 hypo-responders carried the HLA haplotypes (DR11, DQ7 and DR13, DQ6), usually associated with hyperresponsiveness. Both vaccinal cycles provided evidence that infants respond well to vaccination, started at birth, against hepatitis B virus with a high degree of protection.(ABSTRACT TRUNCATED AT 250 WORDS)