pertussis vaccine (DTP) and IPV became available (estimated at the time to require 2 to 5 years); separate administration of IPV was thought to be too difficult to implement. The combined product is still not available in the United States. The 1988 committee further stated that “If it is demonstrated later that 90 percent or more of preschool children are immune without significant pockets of nonimmune individuals, and wild virus is indeed absent from the environment, the use of OPV might be terminated [replaced by IPV] except in special circumstances . . .” (p. 28).
Two major differences affect the current climate of decisionmaking about polio vaccination policy compared with that of earlier years. The first is that poliomyelitis disease from wild virus has been eradicated from the Western Hemisphere. The relatively few cases of polio occurring in the hemisphere are attributable to the live attenuated polio vaccine, OPV. These cases are known as vaccine-associated paralytic polio, or VAPP. Second, incidence of the natural disease has also substantially decreased internationally. However, because natural polio disease has not yet been entirely eliminated from the rest of the world, it is possible for international travelers to bring (import) poliovirus into the country, potentially infecting others and causing disease. The present challenge for policymakers is to decide what action to take until polio disease is eradicated globally. It is to be hoped that the IOM workshop contributed to the ability of policymakers to meet that challenge.
Following presentations on the history and the current status of polio vaccines and on the characteristics of the vaccines themselves, discussion at the IOM workshop centered around five options for vaccination against poliomyelitis: (1) primary reliance on OPV, which is the current U.S. policy; (2) primary reliance on IPV; (3) a sequential schedule in which one or more doses of IPV would be followed by one or more doses of OPV; (4) informed parental choice of the polio vaccine that a child would receive; and (5) cessation of vaccination against poliomyelitis.
This summary begins with a description of U.S. and international experience with polio vaccination, including the importance of such issues as vaccine-associated polio and the risk of importation of poliovirus. It continues with a description of the presentations and discussion of each of the five options mentioned above. The summary is an attempt at a faithful representation of the activities of the workshop. As mentioned earlier, it does not contain conclusions and recommendations, and it is not intended to be an introduction to or primer on issues of vaccination and immunity. For background information on polio vaccination, and immunization in general, the reader is referred to Plotkin and Mortimer (1994).