Vaccines directed against human immunodeficiency virus are not within the scope of this project because of the rather prominent place that such vaccines already have within NIH.
A variety of analytic methods are available for comparative assessments to support priority-setting and resource allocation decisions. In selecting the approach to be used for this study, the committee had to have a means of comparing the anticipated health benefits and costs of vaccine use across drastically different forms of illness, ranging from pneumonia, ulcers, and cancers to temporary and long-term neurologic impairments. Furthermore, although some of the vaccines included in the study are intended to treat illness, most will be used in the more familiar role of preventing disease.
The committee adopted a cost-effectiveness approach that makes it possible to compare potential new vaccines on the basis of their anticipated impact on morbidity and mortality and on the basis of the costs for health care, use of the vaccine, and vaccine development. The analysis cannot provide the value judgments required to determine whether expected health benefits and costs justify a particular investment in vaccine development. The aim of the analysis is to clarify trade-offs in decisions to invest in the development of one vaccine as compared to another. The basis of comparison is a cost-effectiveness ratio that is expressed as cost per unit of health benefit gained. Monetary costs—the numerator of the ratio—reflect changes in the cost of health care that are expected to result from the use of an intervention such as a new vaccine plus costs associated with developing and delivering the intervention. Health benefits—the denominator of the ratio—are measured in terms of quality-adjusted life years (QALYs) gained by using the intervention under study. QALYs are a measure of health outcome that assigns to each period of time a weight, ranging from 0 to 1, corresponding to the health-related quality of life during that period, where a weight of 1 corresponds to optimal health, and a weight of 0 corresponds to a health state judged equivalent to death. These are then aggregated across time periods. The concept of QALYs, developed in the 1970s, was designed as a method that could integrate for an individual the health improvements from changes in both the quality and quantity of life, and could also aggregate these improvements across individuals. QALYs provide a summary measure of changes in morbidity and mortality that can be applied to very different health conditions and interventions. Interventions that produce both a health benefit and cost savings are inherently cost-effective, but many other interventions that do not save costs produce benefits at costs that are judged to be reasonable. An analysis such as the one performed by the present committee is a valuable tool for decisionmakers who must set priorities and allocate resources. It simplifies a complicated picture in which vastly different forms of illness and health benefits