There is a strange misconception around that differential pricing of pharmaceuticals (in which rich countries pay more than poor countries) is a form of subsidy by the rich of the poor. In fact, the opposite is true. If the people in poor countries pay something above the marginal cost – even if only slightly – then they are contributing towards the R&D costs. If you have a single price and so exclude the poor – so that they cannot buy the medicines at all – then they use nothing and contribute nothing. So differential pricing allows the burden of paying for the R&D to be spread more widely, and so the poor, to some (possibly small) extent, contribute to the costs of medicines used by the rich. Which means we should not think of differential pricing as a form of subsidy by the rich to the poor.