That flight attendent who had sex with half of the original cases of HIV was not the cause of the epidemic.
the virus was already here.
The study came from the HepB epidemic information in gay men: Most folks don't know that the valuable vaccine was made from investigating the HepB epidemic. Before these easily found cases were used, Hep B was called "serum hepatitis" and was mainly found in those who got blood, or in medical personnel.