Thinking downstream to accelerate the introduction of new vaccines for developing countries.

Introduction of new vaccines into public health programs in developing countries requires 'translational research', initiated even during the phase of vaccine development, to generate the evidence base necessary for rational public health decision-making. Translational research encompasses assessments of the local disease burden, demonstration projects of vaccines in realistic public health programs, analysis of the economic impact of vaccine introduction, assessment of community and policy-maker perceptions about the importance of a disease and the need to vaccinate against it, and identification of distribution channels and financial mechanisms for deploying and paying for a new vaccine. In the absence of this background information, even a successful vaccine may risk substantial difficulties and delays in its introduction into programs for the poor in developing countries.