The availability of new vaccines for pediatric use provides an unprecedented opportunity to prevent serious infectious diseases and their associated morbidity and mortality. However, each new product entails the need for additional injections that could become so numerous as to discourage the administration of new vaccines. This challenge can be overcome by mixing individual vaccines before delivery such that multiple vaccines are administered as single combination vaccines. Technical, clinical, manufacturing, regulatory and marketing issues relative to combination vaccines in general are the major challenges for ongoing and future development.

If the visionary goals of the Children's Vaccine Initiative (CVI) are to be achieved, it will have to be an initiating, integrating, and propelling force in the development, manufacturing, and use of vaccines. Success in solving the major technological challenges may depend first on solving the problem of incorporating the major players into the CVI. Today's relationship between private vaccine manufacturers and publicsector purchasers must give way to a new era of cooperation and coordination.