Vampires is a good pack, especially if you like playing with supernatural sims. Sims won't spontaneously turn into vampires. You create them in CaS or engage a vampire in interactions to "turn" your sim. The game will create some townie vampires. When the pack first released, some players complained about frequent vampire invasions of their sim's homes and the pack was retuned to decrease the frequency of those events. I've had the pack for a year and have never had a vampire invade my home. You can't toggle off any of the occult types in game options, but there are in game toggles to prevent any vampire visitations, such as placing garlic on windows and doors and using lock designations. There are also mods to give you more control. Frankly, I wish my vampires were a bit more menacing.