Before discussing the results obtained by applying the model developed for this report to the selected candidate vaccines, the committee provides some examples of results obtained from an analysis of a hypothetical candidate vaccine X directed for use for the prevention of disease X.
The characteristics of a base case scenario (Case 1) for vaccine X-1 are presented in Table 4–2. Candidate vaccine X-1 is under development and would be directed against disease X-1, which affects 100,000 people annually. Disease X-1 has a 1% case fatality rate (CFR). All age groups are affected equally. Half of the people experience a mild illness (2-week duration; HUI=.90) and half experience a moderate illness (2-week duration; HUI=.70). The health care costs include a physician visit for patients with mild cases and more extensive and more expensive treatment (including a brief hospitalization) for patients with moderate illness. The candidate vaccine will be licensed within 7 years, after expenditures of $240 million in additional research and development costs. The vaccine will cost $50 for each dose of the 3-dose series, which will be given in infancy. The vaccine will be 75% effective, and 90% of the target population (i.e., infants) will be vaccinated.
In such a hypothetical scenario, the cost per QALY gained by use of the vaccine is approximately $125,000. The number of QALYs lost to disease X-1 is 7,000, almost 6,800 of which are due to the effects of mortality. With the specified assumptions regarding effectiveness and utilization, only 4,700 QALYs would be gained if the vaccine were available immediately. Discounting to allow for the time needed for vaccine development reduces the annualized present value of the QALYs gained to 3,300.
The discounted cost of care saved by this vaccine strategy is approximately $43 million. Program costs for vaccinating all infants with three doses of the $50 vaccine amount to $720 million; adjustments for the rate of utilization and discounting for vaccine development time reduces the annualized present value of those costs to approximately $450 million. Although the investment required to bring this vaccine to licensure is estimated to be $240 million, the amortized amount attributed to a single year is $7.2 million. The net cost (development cost plus delivery costs minus health care savings) is approximately $420 million.
The following examples (Table 4–3) are based on modifications of Case 1 and will demonstrate the effects of changes in target population, program considerations, disease severity, and discounting. This section closes with a description and example of how the cost-effectiveness model developed for research and development prioritization can be used by other policymakers to plan vaccine programs, for example. The chapter then closes with the results obtained for the 26 candidate vaccines chosen by the committee for further illustration.