Apparently the US government decided to test whether penicillin would also work as a vaccine for STDs by deliberately infecting around 700 Guatemalans with syphilis and gonorrhea in the 1940s. Most "participants" were prisoners or mentally ill and did not give consent. You can read more about this from BBC and CNN.
If this reminds you of the now infamous Tuskegee syphilis experiment-- it should. Both happened during the same time period. I wonder where else in the world we have deliberately infected people in the name of science?
