As everyone knows, vampires are un-dead, so I doubt very much they will be too worried about contracting a life threatening illness through infected blood. I hear they don’t even wipe the seat when using a public toilet!.
However, if the vampires victim carries a disease that turns their blood to silver (Kind of a low budget king Midus thing), or garlic sauce (which I’m sure I once had when I worked in France) then I would suspect that the vampire may experience a mild skin condition, flatulence, bad bread, or instant vaporisation of their body while their soul makes a direct journey to hell.