[dalke]

That's what the FDA does now, yes. However, the polio vaccine was introduced when the FDA had weaker powers. It wasn't until after the Thalidomide tragedy and the 1962 Kefauver-Harris Amendment where pharmaceutical companies also needed to demonstrate effectiveness. Before then, companies only needed to demonstrate safety.

As it was, the Cutter polio vaccine incident shows that making the vaccine was not easy.

> I'm sure that Salk knew ...

How are you sure? Is this discussed in his biography or autobiography? I see the topic is covered in Jane S. Smith's "Patent the Sun", but I haven't read it.

Other vaccines (or vaccine preparations) at the time were patented. Was your described behavior typical for them?