Anyone who has any remnants of humanity inside has asked this question.
One answer is no secret to anyone: poor countries. But that’s not always the case, and this is where it gets darker.

The ethics of deliberately infecting volunteers with Covid-19 to test vaccines are a complicated issue only if you value something more than human life, which is actually common, but not the case here. So I’m not making a secret that everything I know and feel made me conclude long ago that most medical tests that occurred on humans were abominations permitted only by a massive lack of empathy / humanity and usually driven by financial incentives. Everything that followed after that was but a confirmation. Point being: I’m long over that debate, there is absolutely no essential difference between the Bayer labs in Auschwitz and the Pfizer Labs in London (or wherever).
And I know a…