Sue Desmond-Hellmann has a problem.
The Bill & Melinda Gates Foundation, of which Desmond-Hellmann is chief executive, is one of the biggest donors to a handful of multibillion-dollar global funds that have made huge strides in combating diseases such as malaria, tuberculosis, polio and HIV. These vast pools of money, backed by philanthropists and government foreign aid budgets, have tilted pharmaceutical markets with bulk orders and fixed on-the-ground logistics so that vaccines and other medications get to hundreds of millions of people who need them, especially in the developing world.