in children 2 years of age or older, but not in infants. It could be argued that the health benefits of an improved pneumococcal vaccine are simply the incremental benefit that could be obtained from extending protection to the child population under 2 years of age who would respond to the conjugated improved vaccine. However, a more reasonable assumption is that the current vaccine would not be used in the developing world for the reason stated above and because the delivery requirement (children 2 years and older) could not conveniently be added to existing vaccination schedules. Additionally, it is doubtful the existing vaccine would be used if the improved version becomes available. Hence, the potential benefits of an improved vaccine are calculated using the entire existing disease burden as a starting point. The proportion of the TDBV that is vaccine preventable is discussed in Appendix D-17.
This analysis does not include calculation of the potential benefits of improving any vaccine that is in widespread use in the developing world. For such calculations it is necessary to estimate the incremental benefits (e.g., in efficacy, disease proportion amenable to vaccine prevention by virtue of effectiveness at younger ages, etc.) or costs associated with its use as compared to the existing vaccine. The analyses of potential benefits for improved influenza and pertussis vaccines presented in the committee’s first report illustrate the approach needed in such calculations (Institute of Medicine, 1985).
The results of the central analysis, presented below, are based on the following assumptions:
the probability of successful development and other vaccine characteristics, e.g., efficacy, described in Chapter 5
a discount rate of 0.05
the IME perspective representing the median of values derived from public health professionals in various developing countries (as described in Chapter 4)
the uniformity of utilization rates across target populations (Chapter 6)
Table 7.4 shows values representing the possible health benefits resulting from the development of each vaccine candidate. Total disease burden values represent the burden of illness resulting from the pathogen(s) against which the vaccine is directed.
Vaccine preventable illness values represent the burden of illness that could be averted by delivering a hypothetical vaccine that is 100