Orphan diseases -- diseases which are common in the poorer parts of the world, but less of a problem in the wealthier parts -- present a particularly thorny problem for global public health advocates: how do you get the world's pharmaceutical scientists working on drugs for these diseases when the markets for them are not likely to be very lucrative? Here's one answer: create prizes.

Kremer advocates constructing a kind of artificial market for a vaccine. A donor would commit to paying a certain sum, a few hundred million dollars up to perhaps $5 billion, on delivery of a viable vaccine. Once a vaccine is manufactured, the donor would purchase it at a high price per dose until the sum is exhausted; thereafter, the company would be obligated to supply the vaccine to poor countries at a low price.

(Thanks, Tony!)