made it feasible to complete testing for only three of the candidate vaccines. The committee chose the universal influenza vaccine, the tuberculosis vaccine, and the group B streptococcal vaccine for this phase for a collection of reasons related to how the candidate vaccines helped capture various health, economic, and vaccine attributes.
For example, the universal influenza vaccine addresses a disease that is important in both high- and low-income countries, and the convenience of a single vaccine for all influenza strains would make it readily useful for all parts of the world. Furthermore, influenza affects all age groups and causes widespread morbidity worldwide. In contrast, tuberculosis does not pose a significant threat in high-income nations, thus a vaccine for tuberculosis would likely be of most use in the low- and middle-income countries. And group B streptococcus vaccine would be pertinent for both low- and high-income countries but is designed for administration to pregnant women (a special population) and would confer benefits to their infants. Additional information on the impact of influenza, tuberculosis, and group B streptococcus can be found in Boxes B-1, B-2, and B-3 in Appendix B.
In its data-gathering process, the committee did not attempt to develop the best or most detailed estimates about each disease. The objective was instead to obtain reasonable data that could help the committee evaluate the model rather than to generate precise projections about specific vaccines.
The committee chose to develop reasonable estimates for data based on literature reviews and expert opinion, and it sometimes also relied upon committee-generated assumptions because much of the information required for the model, especially information concerning South Africa, was not available. It is thus reasonable to view the data inputs as characterizing hypothetical vaccines against influenza-like, tuberculosis-like, and group B streptococcus–like syndromes.
The estimates and assumptions used in this model were based upon literature reviews, publicly available data provided by international agencies such as the World Health Organization (WHO), and publications of various other organizations, such as the Agency for Healthcare Research and Quality (AHRQ) and the Healthcare Cost and Utilization Project (HCUP) in the United States.
For each candidate vaccine, the model used several categories of inputs (see Table 3-1 for specifics):