I would recommend this episode of Radiolab: https://radiolab.org/episodes/great_vaccinator

About Maurice Hilleman who created over 40 vaccines. If I remember correctly, they talk about trials for the polio vaccine and how hard it was knowing that some of the children that were in the study who got the placebo would die, when if they had gotten the vaccine they would have lived. Roll of the dice.

It's not a comprehensive examination of the ethics, but interesting hearing their first-hand experience grappling with it.