The proposed model is based on comparison of the relative potential health benefits calculated for each vaccine candidate. Calculations of potential expenditures on vaccines to achieve these benefits—representing “affordability”—are also made and can be incorporated into the decision process, if desired. This approach combines elements of decision analysis and cost-effectiveness analysis. The approach was selected by the committee because it identifies each logical component contributing to vaccine benefits and costs* without placing a monetary value on human life or suffering. The approach requires substantial amounts of information about diseases and vaccine candidates. Committee members believe that the activity of gathering this information is beneficial in itself; it strengthens the decision-making process and highlights areas in which more research is needed. Chapter 2 describes four other approaches to establishing priorities that were considered and judged less satisfactory.
It should be emphasized that the proposed system is designed as an aid to decision making and not as a definitive answer to the selection process. Rather than merely providing a single list of priorities, the committee also demonstrated with sensitivity analyses how different rankings could result from the adoption of various viewpoints on the affordability of benefits, on the undesirability of illness or death in specific age groups, or from assumptions about disease incidence, the possible effect of new treatments, and other factors that cannot be predicted with certainty.
Several other nonquantifiable issues, all of which concern the policymaker, also must be incorporated into the final judgment on vaccine priorities. These include:
goals of the responsible agency and its schedule for achieving them
ethical questions on the distribution of benefits between socioeconomic or age groups, countries, or regions
most appropriate time at which the agency can exert influence and the opportunity and need for such influence
extent of private sector activities
the desired balance of the development portfolio (e.g., pediatric versus adult vaccines, global versus regional diseases)
arguments that can be made for treating certain vaccine development projects as unique because of their potential for facilitating immunization programs in general (e.g., by eliminating constraints on delivery, such as poor stability) or by improving public confidence (e.g., by reducing adverse reactions)
the prospect that a particular project may serve as a useful model for a number of other desired vaccines
disease related factors, such as epidemiologic and clinical characteristics likely to overwhelm medical services, and the