purchased 351 million doses of oral polio vaccine (OPV), which cost $25.6 million including air freight delivery (John Gilmartin, UNICEF, personal communication, 1993; World Health Organization/Children's Vaccine Initiative, 1992b). It is estimated that to duplicate polio eradication efforts elsewhere in the world, the annual purchase of OPV must increase to $87 million (Agency for Cooperation in International Health, 1992).

Vaccine wastage has been identified as another major problem, not only in terms of cost but also in terms of forecasting the demand for vaccine (World Health Organization/Children's Vaccine Initiative, 1992c). Between 1982 and 1992 the demand for EPI vaccines rose 10-fold (Agency for Cooperation in International Health, 1992; UNICEF, 1991b). This kind of growth in demand has forced UNICEF to try to predict the number of doses needed, so that manufacturers will have enough time to increase their production. This has not been an easy task, primarily because the month-to-month variation in demand for a vaccine can vary as much as sevenfold (World Health Organization/Children's Vaccine Initiative, 1992c). Up until 1990, UNICEF's annual forecast of worldwide vaccine demand was fairly accurate. However, in both 1991 and 1992, countries requested substantially less vaccine from UNICEF than estimated (Terrel Hill, UNICEF, personal communication, 1993). The precise reasons for the decreased country demand for UNICEF-supplied vaccine are not fully understood at this time. It is likely, however, that increased local production of vaccines in some countries has led to decreased country-level demand. In addition, improved national census data in many countries may have resulted in a more realistic assessment of vaccine need. Of great concern, however, is that the decreased demand for vaccine may be a result of a slippage in immunization coverage in many countries (Terrel Hill, UNICEF, personal communication, 1993).

Vaccines are manufactured by both industrialized and developing countries around the world. It is estimated that almost 60 percent of the diphtheria and tetanus toxoids and pertussis vaccine (DTP) currently being used in the world is actually produced in the country that uses it (World Health Organization/Children's Vaccine Initiative, 1992a). The annual production of 500 million doses of EPI vaccines by the People's Republic of China is equivalent to roughly half of all vaccines purchased by UNICEF each year (Agency for Cooperation in International Health, 1992). Currently, OPV is produced or bulk finished in over 25 nations (of which half are considered to be developing countries). (The quality control requirements for the production of OPV differ from those for the finishing