I'm thinking that we're looking at a few factors at least, once it become obvious that we're looking at bodily fluid exchange. The first would be an even stronger "Jesus Freak" movement in response to the plague. The second would be an aborted gay rights movement, once it became clear that the virus was being more prominently transmitted there (after a crossover from the straight community). While one could argue that the AIDS epidemic caused a stronger gay community in terms of visibility and political influence, it was only due to the previous post-Stonewall visibility that they had anything to build on. The third would be--of course--a sharply curtailed sexual revolution, even for those who do not turn to religion.
Culturally, I can see the burgeoning sex industry (pornography, strippers, and so on) as facing major opposition from new local ordinances stemming from a health-oriented movement. We'd also be less likely to see the OTL loosening of network standards, which butterflies away much of what was interesting on television in the 70s.