Ah, but the plague then infected the internet.
As it was designed to target any and all files with the meshes and textures of Oblivion, an epidemic broke out. Now, all across the world, you'll find that nobody plays Oblivion on their consoles anymore. At least, not while within distance of a wifi hotspot.
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Okay, in all seriousness... I don't know about Vampirism much.
If they clearly defined exactly how the infection which causes vampirism spreads in the Elder Scrolls universe, that would be one thing. But instead, their diseases seem to spread arbitrarily by contact. As in, just being around the NPC/Critter for long enough in Morrowind.
In Oblivion, I think they -at least- have to attack you... but I can't swear to it.
It'd be interesting to see... but... I don't know. It might not play out the way you'd expect, either.