April 2000 - Demand for AIDS vaccines varies by level of risk and by national wealth. At-risk individuals in poor countries suffer on both counts. Providing funds to develop and distribute AIDS vaccines should be a global concern. Bishai, Lin, and Kiyonga delineate two different algorithms for the purchase of AIDS vaccines, to show how differences in policy objectives can greatly affect projections of the number of courses of vaccine that will be needed. They consider a hypothetical vaccine costing