must be assessed separately under each possible list of alternatives before the optimal group is selected.
Aside from determining interdependence among vaccines with respect to costs and effectiveness, NIAID may wish to consider certain goals with respect to specific target populations or diseases. For example, the individual rankings might reveal that vaccines K, L, and M are all of higher priority than vaccine N. However, if K, L, and M all benefit populations in one region (e.g., Africa), while N benefits the population of another region (e.g., South America), then a portfolio of three vaccines might reasonably include vaccine N along with K and L. In other words, a pairwise comparison might reveal that M is preferred to N, yet the portfolio (K, L, N) is preferred to the portfolio (K, L, M). This kind of effect may be examined as a second-order iteration after the initial rankings are in hand, or it may be built into the process by examining each possible combination of vaccines separately. However, if there were 20 candidates, and the objective was to pick the top 5, for example, then the latter approach would involve examining
combinations of 5, rather than just 20 individual candidates.
Several different criteria could be used to compile portfolios in establishing vaccine priorities for important diseases in developing countries. As the example illustrates, one criterion might be the geographic boundaries of the target population. Another might be the level of development. The needs of the world’s poorer nations may be quite different from those of developing countries that have progressed further. A third criterion might be the age range of the principal target population; diseases that affect young children may be considered separately from those that attack adults in certain occupations (e.g., in some parts of the world, young men who work in forested areas have a high risk of yellow fever).
The selection of an appropriate method is the first step in setting priorities for accelerated vaccine development. This chapter reviews five methods that have been used successfully in other efforts to choose among health-related investments: (1) multiattribute accounting, (2) multiattribute scoring, (3) decision analysis with multiple objectives, (4) cost-effectiveness and cost-utility analysis, and (5) benefit-cost analysis.
All of the methods require a mixture of factual information, carefully defined estimates, and subjective judgments. They differ in the extent to which they specify how the various elements should be combined. Multiattribute accounting, which requires the fewest