The Jeremiah Metzger Lecture. Vaccine prophylaxis today: its science, application and politics.

In summary, I have addressed 5 key issues concerning vaccines today. First is the essentially empiric nature of vaccinology. Vaccinology is not a rational science. Each idea must be tested by experiment. This need for trial and error experimentation is a substantial barrier to new vaccines. The proven track record of existing vaccines to eradicate disease, to reduce occurrence of disease, reduce human suffering and contain health care spending--when coupled with the potential for new discoveries against significant disease targets--is unparalleled by other therapeutic areas. The complexity of vaccine delivery today in clinical practice with 15-17 injections in the first two years of life emphasizes the need for development of combination pediatric vaccines, for example, putting DTaP, HBV, HIB, and IPV together. This has proved to be far more difficult than previously believed due to unpredicted immune interference and incompatibilities on mixing of different components, demonstrating again the inadequacy of our understanding of how vaccines work and the empiric nature of the science. Similar complexity will face adult vaccines in the future, as new adult vaccines are developed. Next, vaccines remain undervalued by people, by government, and by society. Government-controlled prices in many areas of the world prohibit a return on investment that supports innovative R&D. New vaccines may be unavailable in certain markets because of pricing restraints. Prices of new vaccines in the developed world will rise as will prices in the developing world for products currently available only in the developed world. Reluctance to use vaccines is an especially disturbing symptom of the undervaluation issue. In the U.S., school entry requirements have kept childhood immunization rates high by five years of age. But this is a new phenomenon, driven in part by the measles outbreaks. The risk is that history will repeat itself. In the absence of disease and lack of public knowledge of these diseases, complacency sets in, immunization rates fall, with the expected result on occurrence of disease. For adults, we may hope that managed care with its interest in cost saving and disease prevention may actually help in achieving the goals of the Year 2000. Finally, I have talked about the anti-vaccine attitudes and forces that impede control of disease by vaccines. It is important that new initiatives be undertaken that will be successful in providing a balanced view of vaccine safety, efficacy and benefits to the public, to the provider and to the payers.