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Clinical relevance of lower Hib response in DTPa-based combination vaccines
J Poolman1, A Kaufhold, D De Grave
1SmithKline Beecham Biologicals, Rixensart, Belgium.
Insights
Combination vaccines, like diphtheria-tetanus-acellular pertussis (DTPa) with Haemophilus influenzae type b (Hib), induce similar antibody quality and immune memory. This suggests the DTPa-HBV-IPV/Hib combination vaccine is likely effective against Hib disease.
Area of Science:
- Pediatric immunology
- Vaccinology
- Infectious disease prevention
Background:
- Combination vaccines simplify infant immunization schedules.
- Some DTPa-Hib combinations show lower Hib antibody titers compared to separate administration.
- Assessing the immunogenicity of combined vaccines is crucial for public health.
Purpose of the Study:
- To evaluate the antibody response to a DTPa-HBV-IPV/Hib combination vaccine.
- To compare the quality and function of antibodies induced by the combination vaccine versus separate Hib conjugates.
- To determine if the combination vaccine induces immunological memory against Haemophilus influenzae type b.
Main Methods:
- Infants received a primary series of either a DTPa-HBV-IPV/Hib combination vaccine or separate Hib conjugate vaccines.
- Antibody levels (titers) were measured post-vaccination.
- Antibody quality was assessed by isotype, IgG subclass, avidity, and opsonic activity.
- Immunological memory was evaluated.
Main Results:
- The DTPa-HBV-IPV/Hib combination vaccine resulted in lower overall antibody levels (titers) against Hib compared to separate Hib conjugates.
- However, the nature of the induced antibodies (isotype and IgG subclasses) was comparable.
- Antibody function, including avidity and opsonic activity, was similar between the groups.
- Immunological memory was successfully induced by the combination vaccine.
Conclusions:
- Despite lower antibody titers, the DTPa-HBV-IPV/Hib combination vaccine elicits antibodies of similar quality and function.
- The induction of immunological memory suggests the combination vaccine is likely to be efficacious in preventing Hib disease.
- Combination vaccines remain a valuable tool for efficient infant immunization.
Abstract:
Combination vaccines are essential to enable administration of all the required antigens in routine infant immunisation schedules at any single visit. Some combinations of diphtheria-tetanus-acellular pertussis (DTPa) with Haemophilus influenzae type b (Hib) conjugate vaccines have been shown to result in lower Hib titres than when Hib is administered separately. While confirming that a primary series with a DTPa-HBV-IPV/Hib combination gives lower antibody levels than separate Hib conjugates, we show that the nature (isotype and IgG subclasses) and function (avidity and opsonic activity) of the antibodies are the same, and immunologic memory is induced. It is likely therefore that the DTPa-HBV-IPV/Hib combination will be efficacious against Hib disease.