Speculative Question re Vampires

So. If you invite a vampire into your house, they can come in.

If you then move house, and someone else buys it, the vampire can't come in anymore.

But... If you have two people living in the house (person A and person B), and A invites the vampire in - so the vampire can come in - and then A moves house (and B is still living there), and then person C moves in, and after B and C have shared the house for a while, B moves out, so that C is living there alone...

...at that point, can the vampire still come in?