The science of vaccines in present and future perspective.

Vaccinology, while affording great opportunities in the prevention of infectious diseases, also poses the problem of stretching the possible beyond the practicable. Politics, economics, and technology all come together at the point of resource allocation. It is important to maintain a balance between expenditure for the development of vaccines and for the application of vaccines if maximal good is to be achieved in this new era of technical opportunity. A promising approach is to include in single "polytopic" vaccines the largest number of immunogenic epitopes for the greatest number of important diseases.