(price) of the vaccine for the immunization program (Cv in Figure 3.2) is included, the cost of vaccine administration is a primary economic impact that is not included in the analysis. As discussed in Chapter 6, it was assumed for the purposes of this analysis that all vaccines would be delivered through the World Health Organization’s Expanded Program on Immunization (WHO-EPI). All vaccine candidates could then reach the level of utilization achieved by that program, and differences in utilization need not be incorporated as a factor in the analysis. Similarly, the cost of vaccine administration is assumed not to be significantly different between vaccine candidates if all are delivered through the EPI (although there may be some differences in cost, e.g., between injected and oral vaccines).
The first volume of the committee’s report (Institute of Medicine, 1985) presents a method that can be used to estimate the net costs associated with vaccine use, where the cost of treatment averted and differential vaccine utilization are incorporated into the calculations of costs and health benefits. This more detailed approach may be possible where these factors can be reliably estimated, for example, within a specific country.
Secondary impacts of vaccines deal with changes in the costs of care for patients who avoid having the disease in question or who develop side effects requiring treatment. (These impacts are sometimes called “induced costs and savings.”) For the reasons discussed in Chapter 4, it was judged impractical to attempt to estimate global averages for treatment costs for the conditions resulting from the target diseases. The tertiary impacts, which are also not considered in this analysis, involve changes in the costs of care for other diseases that the patient may get because the vaccine has prevented death due to the target disease.
This analysis covers vaccine priorities for the population of the developing world as a whole. It aggregates vaccine benefits and costs irrespective of the local, national, or regional groupings affected by particular diseases. Chapter 4 contains the working definition of the developing world adopted for this analysis.
The analysis treats each potential vaccine as an independent investment decision. For example, the analysis, for reasons discussed in Chapters 4 and 8, does not attempt to incorporate quantitatively the synergism that exists between some diseases, resulting in mortality or more severe morbidity (e.g., measles and diarrhea). Thus, some vaccines may in practice avert a disease burden greater than that nominally attributable to the pathogens against which they protect. Additionally, the analysis does not take into account other interactions, such as the effect of an improved pertussis vaccine on the long-term acceptance of immunization in general or the benefits of an improved polio vaccine on the ease of delivery of other childhood vaccines (see Chapter 8).
The method of estimating disease burdens used in this analysis treats diseases as noninteracting phenomena, although possible interactions are recognized as a factor for consideration in the final choice of priorities for accelerated development. If it becomes possible to better quantitate known or suspected interactions, for example, between measles and diarrhea or between viral and bacterial