Paradiso P R
Lederle-Praxis Biologicals, Rochester, New York, USA.
Ann N Y Acad Sci. 1995 May 31;754:108-13. doi: 10.1111/j.1749-6632.1995.tb44443.x.
The ability to combine the standard DTP and Haemophilus b conjugate vaccine considerably simplifies the childhood immunization schedule and process. In addition to reducing the number of immunizations by half, the combination product reduces administrative aspects associated with vaccination including tracking. Simplification of the immunization process should have a positive impact on the vaccine delivery and utilization. Perhaps more importantly, an ability to create combination vaccines will be critical for inclusion of new antigens appropriate for infant vaccines. The combination of DTP and HbOC reduces the number of immunizations routinely given at 2, 4, and 6 months of age by half. Since it is unlikely that parents or pediatricians will accept more than two shots per visit, this reduction is critical. As new vaccines are licensed for such important childhood pathogens as Streptococcus pneumoniae and respiratory syncytial virus, designing stable combination products will become even more critical. Having stated that, we must also not lose site of the fact that combination products must meet the criteria for stability, safety, and efficacy comparable to the separately delivered products. These considerations are not trivial. In the development of Tetramune (DTP-HbOC), stability of the product and consistency of the immune response were critical design parameters for both the preclinical and clinical research. Likewise, the experience with other DTP-Haemophilus b combinations has shown that simple mixing of products prior to injection can reduce the immune response in ways that are not necessarily predictable. In contrast, the response to each of the components of Tetramune was in fact higher than when the vaccines were given separately. This increased response to all of the antigens was not anticipated based on the vaccine composition and points to the need for not only physical characterization of new combinations, but also clinical testing of final combined products before they are introduced for routine use.
