I can give you the more common ones, at least. As I've mentioned, "vampire" is a fairly large umbrella term for a varied subset of creatures, and those variations can make a significant amount of difference. That said, it's far more likely that a variant will prove immune to something unexpected rather than unusually susceptible to something unexpected, so my list should cover you on the basics.
I see. So it's possible he's masking the extent of his infirmity behind a stimulant already.
...Ugh. Like I said, I'm not a doctor, but I hate not being able to offer some type of avenue to pursue. Is it possible the blood he's imbibing is the wrong type somehow? Like a vegetarian with a nutrient deficiency. Rather than having taken in something actively harmful, maybe he's not getting enough of something he needs?
no subject
I see. So it's possible he's masking the extent of his infirmity behind a stimulant already.
...Ugh. Like I said, I'm not a doctor, but I hate not being able to offer some type of avenue to pursue. Is it possible the blood he's imbibing is the wrong type somehow? Like a vegetarian with a nutrient deficiency. Rather than having taken in something actively harmful, maybe he's not getting enough of something he needs?