Challenges in the development, licensure, and use of combination vaccines

Before substantial public health benefits associated with use of combinatio n vaccines can be realized, a variety of challenges must be addressed. In F ebruary 2000, the National Vaccine Program Office convened the Internationa l Symposium on Combination Vaccines to explore solutions for barriers to de velopment, licensure, and use of safe and effective combination vaccines. T he symposium focused on the following questions: (1) What immunologic stand ards should be used to evaluate new combination vaccines? (2) How should co rrelates of protection be developed, and how should the data they provide b e interpreted? (3) What sample size is adequate for prelicensure safety tri als of combination vaccines? (4) Should standards for evaluation of combina tion vaccines containing licensed components be different from standards fo r evaluation of combinations containing unlicensed components? (5) How can the "great expectations" of postlicensure surveillance be realized? Availab le data relevant to these issues were presented, providing a foundation for furthering the science of combination vaccines.