spective for measuring health effects and costs; a domestic perspective for identifying diseases of significance; an incremental perspective regarding the benefits that the vaccines under study would bring in comparison to current forms of care; and a steady-state perspective for assessing likely levels of vaccine use.

A societal perspective for measuring health effects and costs in the United States means that all significant health outcomes and costs are taken into consideration, regardless of who experiences them. Thus, if use of a vaccine reduces hospital care costs, the analysis does not have to distinguish between cost savings that accrue to individuals and savings that accrue to insurers.

The societal perspective can be contrasted with a more selective perspective, such as that of a particular government agency, health plan, or vaccine manufacturer, that might be used to examine these factors in other analyses. For these more selective analyses, the assessment of health effects might be limited to the members of a health plan or to a particular age group such as the Medicare population. Similarly, the costs (or savings) included in the analysis would be limited to those that would be incurred by the particular agency or organization. Costs borne by individuals or other organizations would not be considered in the analysis. A societal perspective, however, examines all costs and the health experience of the entire population.

The analysis also reflects the domestic perspective in the charge to the committee. The vaccine candidates analyzed in depth were selected on the basis of their relevance to health status in the United States, not globally. Thus, for the vaccines that are likely to be used in many countries in addition to the United States, the analysis includes only a portion of the total health benefits and savings in costs of care that can be expected for relatively little additional investment in vaccine development. Excluded from the analysis are other vaccines that would be valuable for conditions that are important health problems in other countries, such as malaria and schistosomiasis, but that pose little threat in the United States. The committee would have liked to have examined the effect of a global perspective on the results of the analysis. To do so would have greatly increased the committee’s task and would have introduced sufficient uncertainties into the estimates that their relevance for domestic policy would be greatly undermined. Additional discussions of conditions of particular importance outside of the United States appear in Chapters 3 and 7.

The cost-effectiveness ratios calculated for this study represent the estimated incremental changes in costs and health effects that can be expected with the use of a new vaccine compared to those from the use of current forms of prevention and treatment. For the vaccines against influenza and Streptococcus pneumoniae, the analysis must also consider the costs and health effects associated with the use of existing vaccines.

The committee has based its analysis on the patterns of annual vaccine use that are expected at the point at which a “steady-state” of usage has been achieved. When a vaccine is first introduced, initial patterns of use can be expected to be unstable and to differ from those that will be seen in later years when