In 1985, the Institute of Medicine (IOM) released two related reports titled New Vaccine Development: Establishing Priorities Vol. 1, Diseases of Importance in the United States and Vol. 2, Diseases of Importance in Developing Countries (IOM, 1985a,b). The project had been commissioned by the National Institutes of Health (NIH) as part of its planning for the future. The committee assembled for that project developed a quantitative model that could be used by decisionmakers to prioritize the development of vaccines against a number of disparate infectious diseases considered significant threats to public health. The variables included in that model were disease burden, costs of care, vaccine program costs, vaccine acceptance, vaccine development costs, and the likelihood of success. For volume 1, data on 14 candidate vaccines against diseases of domestic importance were analyzed with the model. Several of the candidate vaccines considered in that report have in fact been licensed since its publication. Vaccines against hepatitis B virus (recombinant), hepatitis A virus, varicellazoster virus, Haemophilus influenzae, rotavirus, and pertussis acellular vaccine are all now part of the disease prevention armamentarium. The rest of the candidate vaccines are still in the pipeline.
Ten years later, NIH requested that IOM convene a new committee to assess the progress made since publication of the reports in 1985, discuss important barriers to vaccine research and development, and develop another quantitative framework for prioritizing vaccine development. There are two important differences between the landmark project completed in 1985 and the current project:
The current analysis focuses on conditions of domestic public health importance. There is no second report on international concerns; and
The committee was explicitly asked to consider therapeutic vaccines directed against chronic conditions such as autoimmune diseases and cancers.
CONSIDERATIONS RELATED TO THE MODEL AND THE STUDY
Before embarking on a discussion of the methods used and the results obtained, it is necessary to present several caveats, as well as an historical perspective of vaccine development since publication of the 1985 report. This report, particularly the appendixes, is not the definitive cost-effectiveness analysis of any one specific vaccine-based prevention or treatment strategy. For several of the conditions under study in this report, detailed and elaborate economic analyses have been conducted and published by other researchers. For other conditions, there are none. Published studies, however, rely on different assumptions and apply different techniques. Thus, the committee could not depend on the results in the published literature for comparable estimates of the economic burdens of the conditions to be studied.
In order to compare candidate vaccines with each other, as this committee was charged with doing, the analyses needed to be conducted in comparable ways. Resource limitations meant that the committee focused on big picture descriptions of disease burden and potential gains from vaccine use. Because fine details regarding epidemiology, clinical presentation in individuals and within a population, and costs of care are not always readily available for the 30 candidate vaccines considered, the committee necessarily made many assumptions for the data used in the model. The committee assessed the published literature and the opinions of experts in the field, and then the members of the committee used their collective scientific and clinical judgment to estimate values when there was no published consensus.
Third, the committee knows that there will be readers of this report who will object to the individual numbers used in (or omitted from) the analyses. The committee urges all readers to consider the report and its appendixes as a whole and believes the following questions can be answered in the affirmative:
If individual values for a given parameter of a given disease seem contrary to expectation, are they relatively correct compared to the values for the other conditions?
Do the data used as a whole represent an unbiased qualitative synthesis of the published values?
Are all conditions being treated similarly?
The committee offers the model as a tool for decisionmakers as they assess the needs for vaccine development and the opportunities for a vaccine development strategy. An untested model would be highly suspect. Therefore, the committee used data in the model that represent the consensus of the scientific community.
The committee intends this model to be used as a dynamic instrument for the responsible prioritization of vaccine development and vaccination program implementation. The basic model and the mathematics used to create the model are described in detail in Chapter 4 and 5. Anyone with a personal computer and a spreadsheet software package could reprogram this model. Those with a mathematical understanding of modeling could do so quickly and easily. A reader could change the basic model if he or she so desired. A reader could change the data run through the model if the reader takes great exception to the data used by the committee. In order to facilitate such use of this model, it can be accessed electronically without charge (see Appendix 27). The committee also believes that this model has great utility even for those not charged with prioritizing vaccine development. Because only part of the model accounts for vaccine development time and costs, the model can be used after licensure of a vaccine to study and plan for vaccination program implementation.
ORGANIZATION OF THE REPORT
Charge to the Committee
The Committee to Study Priorities for Vaccine Development was charged with three main tasks:
Assessing the progress in vaccine development since publication of the 1985 IOM report.
Describing barriers to vaccine research and development.
Developing a framework by which vaccine research and development could be prioritized.
The first part of the charge is addressed in Chapter 2. The second task is addressed in part in Chapter 2 and in part in Chapter 7. The third part of the charge is addressed in Chapters 4 and 5. The application and interpretation of the analytic framework are discussed in Chapters 5 and 6 and the appendixes. It is important to discuss the specifics of the committee’s third task with particular emphasis on what it does not entail. Specifically, the committee was asked to develop a model that could be applied to diseases affecting the U.S. population. As discussed in several places within the report, this influenced specific variables in the model and the choices of candidate vaccines to be used to illustrate the model. This restriction also caused the committee great concerns. Concerns about international health and disease burden are expressed in this chapter and in Chapter 7, Observations.
The committee was also asked to exclude vaccine candidates directed against human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS). Research and development (R&D) related to these vaccines is a priority of the National Institutes of Health (NIH) and many vac
cine R&D companies. The rapidly changing dynamics of basic, clinical, and applied research related to HIV and AIDS could make any assumptions used in the application of the model obsolete before the report is published. The committee notes, however, that one could apply this model to HIV vaccines. The committee was also asked to consider vaccines that it thought could be licensed within the next 10 years or within the decade after that.
Committee Membership and Meetings
The committee was established in the winter of 1995. National Research Council policies on bias and conflict of interest were observed. These policies necessitated excluding from committee membership anyone employed by or with significant financial interest in any vaccine research and development company. In assembling the committee, individuals with expertise in economic modeling, public health, ethics, epidemiology, immunization policy, infectious diseases, vaccinology, immunology and pathology, and clinical medicine were sought. The committee, whose members are listed at the beginning of this volume, consisted of individuals with expertise in all of these areas. The committee met as a whole seven times. Five small-group meetings were also held throughout the deliberations. The committee also sponsored two public workshops on the science base for new vaccine development. Summaries of those workshops can be found in Appendix 28. The purpose of the workshops was to supplement the knowledge of the committee on the current science base of vaccine development as it narrowed the scope of the vaccine candidates to be included in the analysis. The committee also heard presentations from program officers at NIH, staff members responsible for federal data sources such as those managed by the National Center for Health Statistics and other components of the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration, and representatives from vaccine R&D companies.
As will be described in a subsequent section of this chapter, the committee also enlisted the aid of many experts on the conditions and candidate vaccines under consideration. They did so by asking for responses to targeted questions about disease epidemiology, clinical care issues, and vaccine development issues. The questions and a list of the experts who responded can be found in Appendix 29.
Organization of the Report
The report is organized as follows: Chapter 2 describes progress in vaccine development and in basic biomedical sciences important to vaccine development since publication of the last reports in 1985. Chapter 3 describes the choice of candidate vaccines. Chapter 4 gives an overview of the analytic model and the methods used in the analysis and presents the results. Chapter 5 gives a detailed
explanation of the model. Chapter 6 offers a discussion of ethical issues in modeling exercises and measures of quality of life and caveats that should be used in interpreting the results of the model. Chapter 7 concludes the report with some observations regarding vaccine research and development. The main body of the report is followed by appendixes that provide and discuss the condition-specific data used in the calculations.