The answer is, by and large, doctors. Within the hospitals they really do have the power of life and death, deciding who gets treatment when supplies are thin.

The answer is, by and large, doctors. Within the hospitals they really do have the power of life and death, deciding who gets treatment when supplies are thin. Generally the decisions are made using the heuristic of "With this limited stock of X, who should we give it to to save the maximum possible number and quality of lives?" It's not playing god, it's just making rational decisions in times of scarcity. That's something humans do constantly, no god necessary.