Scientific American discusses the need for better forecasting of need for drugs and vaccines:
Unpredictable demand creates a three-way catch-22 problem, as pointed out in a 2002 study commissioned by the GAVI Alliance, formerly the Global Alliance for Vaccines and Immunization. Poor countries have to know the price of a vaccine to see if they can afford it. Manufacturers, however, are hesitant to set a price unless they know how many doses will be bought. And aid donors cannot be sure they can subsidize a purchase without knowing the price and quantity of the sale. Vaccine purchases have occurred anyway, but not without difficulty. In 2002, when GAVI convinced suppliers to manufacture extra courses of an existing vaccine against Haemophilus influenzae type b, poor countries were slow to buy it. "We were very naive at that time and thought countries would take up the vaccine much faster than they did," recalls Michel Zaffran, the group's deputy executive secretary. "The tools that we had available were very poor."
I am not personally convinced that the problem is forecasting demand in the sense of uncertainty about how many doses of vaccine we are likely to need. In principle, the number of children in a cohort, the extent to which they are at risk of particular diseases, and the the capacity of health services to reach them with vaccines, are all likely to vary little from one year to another.
The big driver of uncertainty in demand seems to be the behaviour of donors, capriciously moving money from one priority to another according to the latest political priority or development fad, or unpredictably dumping their unspent budget at the end of the year on easy-to-buy goods such as pharmaceutical companies. As well as improving our techniques for forecasting demand, we need to take a long hard look at how we can make aid budgets more predictable, so that developing countries have much more information with which to plan, long in advance, how many drugs and vaccines they will be able to afford.