resulting from the adverse reactions are used to calculate values representing the potential burden of vaccine-induced illness. Where applicable, these values are then used to adjust PRMM values in the derivation of estimates for net potential health benefits (Figure 7.1).
An example of such a calculation is included in Appendix C to illustrate the procedure. Only three vaccine candidates are expected to have adverse reactions that might be equivalent to conditions serious enough to be included in the morbidity categories described in this report. Preliminary calculations of adverse reaction values for the three vaccines resulted in all cases in values less than one-half of one unit (generally well under 1 percent of the PRMM). All were considered negligible in relation to the total PRMM values for the vaccines.
In the tables and discussion that follow in this chapter, adverse reaction values and their costs are not included for the reasons described above. If other vaccine candidates are added to the analysis, however, their potential for adverse reactions should be evaluated.
The purpose of the program of accelerated vaccine development is to expedite the realization of the benefits theoretically possible with various vaccines. It is appropriate, therefore, to consider the times at which benefits and costs associated with vaccine development and use would occur. This is normally done through a process termed discounting (Weinstein and Stason, 1977). Discounting can be applied both to the health benefits (of morbidity and mortality averted) and the costs involved (saved or incurred) in vaccine development and use.
Time to Licensure Factors affecting the predictions of the time it will take to develop the vaccine candidates are discussed in Chapter 5. The predictions are related to probability of success and other issues discussed in that chapter and shown in Table 5.1.
Time to Adoption and Steady-State Yield of Benefits After licensure, the utilization of a vaccine increases until it reaches a steady state. The costs of the vaccination program also increase to reach a steady state (as would the numbers of adverse effects, if applicable). The rate at which a vaccine is adopted depends on physician and target population attitudes toward the new vaccine. The issues determining these are similar to those discussed in Chapter 6.
The Centers for Disease Control, under the auspices of the United States Public Health Service’s 1990 prevention objectives (1980), has adopted a goal of 50 percent or greater utilization for new vaccines at a time five years after licensure. While the utilization rate predicted by the committee for some vaccines is less than 50 percent,