@crinrict is right that vampire breakins don't happen very often anymore. But they will still happen. What I found is that it happens most often in a single sim household that goes to bed early, before midnight. It still happens occasionally in multiple sim households but if any sim in the household is awake, then they won't break in. My vampires do come around on a more or less regular basis but usually my sims are awake so they just knock. If I ignore them, they go away eventually. But I think, but am not sure, that if you invite them in once, that it might improve the odds of one coming back when your sim is asleep and breaking in. Also don't have any garlic in the house and don't use the vampire lock on the door. Another thing I am not sure about but it seems to happen more often after you have played vampire households for a while and bought them perks. Then you might see them more often.
But tbh, the odds of a vampire breakin are very low now. I haven't seen one in a long time. It is certainly less likely now than it uses to be.
Hope this helps.
Thank you so much
