successive steps of development.
This chapter describes the various phases of vaccine development and a number of obstacles that can arise in this process. These barriers can discourage initial investment or prevent the vaccine from advancing beyond a certain stage. At every step, commercial manufacturers weigh the likelihood of product success against its market potential.
The decision-making process for the development and production of vaccines should be guided by an assessment of critical public health needs. Priorities should be established and the desired vaccine characteristics should be defined. In this way, the vast resources of the U.S. and international public and private sectors can be directed to a set of common and complementary goals.
There have been major efforts over the past decade to establish priorities for vaccine development (Institute of Medicine, 1986a,b; National Institute of Allergy and Infectious Diseases, 1992a,b; World Health Organization, 1991; World Health Organization/Children's Vaccine Initiative, 1992c). As discussed in Chapter 3, much of the basic vaccine research conducted by the National Institute of Allergy and Infectious Diseases (NIAID) targets the development of priority vaccine candidates identified in 1986 by the Institute of Medicine (Institute of Medicine, 1986a,b; National Institute of Allergy and Infectious Diseases, 1992a,b), and much progress has been made (National Institute of Allergy and Infectious Disease, 1992b).
At present, new efforts are under way to develop priorities for vaccine R&D. The Task Force on Priority Setting and Strategic Plans of the World Health Organization's (WHO's) Children's Vaccine Initiative (CVI) recently completed a major cost-effectiveness assessment of vaccine-development priorities, and the WHO/United Nations Development Program's (UNDP) Program for Vaccine Development maintains a list of priority areas for vaccine development. In addition, the World Bank, as part of the World Development Report of 1993, Investing in Health (World Bank, 1993), is using Disability Adjusted Life Years to estimate the burden of disease and priorities for intervention.
Whatever priorities are set by the public sector, the ultimate decision to develop and manufacture a vaccine for general use in the United States rests entirely with the commercial vaccine manufacturers (see Chapters 3, 4 and 5 and Appendix H). Commercial manufacturers vigorously pursue the development of those products with market potential (see Chapter 4). Vaccines used exclusively in the developing world hold little promise of