How "in your face" are the vampires?

Hmmm, I will look it up, but I'm positive a guru said that was the way to prevent vampires from acting out in your save -- not doing anything at all vampire. If you have already triggered it, though, there's no way to turn it off. But it works for almost everyone -- if that doesn't work for you on a save where you're sure you did nothing vampire, you probably should repair your game. However, you cannot answer the call from Vlad, you cannot look up vampire lore on the computer, and in conversations, you cannot choose anything with a bat next to it. If you do those even once, the vampires will come.

Edit: In any event, if you want to buy the pack for the build/buy options, you can always try modding them out. TwistedMexi had a mod for awhile but he hasn't updated it. However, there is a new mod out that should do the same thing, but without the toggle that was built into TwistedMexi's mod. http://www.modthesims.info/download.php?t=603329