Is there a some secret sign or plant or something that attracts Vampire to one's home?

Btw, locking all the doors (household members only) has worked for me, even against Vlad himself...though this was before the Nov. patch. Worth trying, anyway, in case it works for you, too.

If nothing else, you can enter each vamp's home and use cheats to reset all their vamp points. Then don't give them the ability to enter homes without permission, to resist garlic, to make more vampires, etc. Weaken those suckers! Then play without fear.

Don't forget to un-toggle the 'played households' button to put the vamps back in the 'unplayed' category, if that's what you'd prefer.