Actually when Lupin returns, he does a lesson on hinkypunks. Unless you are saying he does lessons about vampires later on? But I don’t remember him doing so.
Thanks for the catch. This woman has some ideas (spoilers for the first five books and speculation within) and details every vampire reference in HP thus far. There is a vampire lesson, but its’ later in the book.
Interesting… though I wish she’d say which chapters those quotes were in, because in my paperback version, I can’t find them anywhere at all.
Just saw it… a few lines mentioning it, though nothing more. Not sure if she was subtly trying to point the finger… Snape shows up as Harry and Nevile discuss the assignment or if it was just how it ended up (there are conspiracy theories everywhere in HP land ;))
While not in the books, the trading cards in the video games do have some vampire cards in the set. I really don’t remember anything else about them though, and I’m not sure if they would really count, but they are there.
They are mentioned, and quite early in the books, too…
Well, he does assign a vampire essay (much) later on – it’s mentioned in the scene where he confiscates the Marauder’s Map from Harry. I really doubt Snape is a vampire, though. I mean, the professors eat in front of the students – you’d think that after five years, somebody would mention it if Snape made a habit of drinking blood at mealtimes.
:: is struck by a sudden idea :: Hey, how about Professor Trelawney? She rarely eats in public, and I don’t think we’ve ever seen her out in the sunshine. Maybe it wasn’t cooking sherry in that bottle, after all… 
The other problem is that while Dumbledore may tolerate a werewolf (who can take a potion) as a teacher, would he tolerate a vampire? I don’t know how any potion would work, since they do need blood to survive. Having a bloodthirsty person need children all day wouldn’t be too wise, IMO.
It’s strongly implied that vampires don’t need blood – or at least human blood – to survive in the Potterverse. There are blood-flavoured lollypops made for their use, and the Ministry for Magic says you can’t hunt vampires (source: Fantastic Beasts and Where to Find Them) – they’re protected. I doubt they’d do that if they weren’t preying on humans.
I suspect that the Ministry tolerates them so long as they control their urges. They may be the equivalent of an ex-heroin junky in Rowling’s world – everyone nervous around them, lest they return to bad old habits.
They may not even be undead – she’s never said so, and she’s radically altered all other old legends (look what she did to fairies).
I think there’s a real possibility Snape is a vampire or a half-vampire. Have we ever seen him actually eat? Trewlaney’s an interesting theory, as well, Fretful Porpentine – I’d have never suspected her.
(I always took trewlaney as a satirical version of Lady of Shallot. After all, she spends all her time in a tower staring at the world through a crystal ball – like the Lady’s mirror. Rowling has all kinds of sly, usually comical, references to Arthurian lore peppered throughout the books).
And Guinastasia, that “garlic smell” was Voldemort. Apparently being possessed makes you smell awful – I wonder if Ginny had that problem?
Ah, found an interview transcript that puts the kibosh on the Snape theory:
And I’d be shocked if Trelawney was seriously a vampire, to the point where I may have to add it to my Big List O’ Things That Would Make Me Become A Professional Gambler If They Happened In the Harry Potter Books.
Knowing the status of vampires in fantasy history (as compared to werewolves, who do have the possibility for good… when they aren’t in wolf form), I think we may see one as a Death Eater. Perhaps Malfoy is a close vampire? 
I believe Professor Flitwik (sp?) in the first book, was rumored to have had a run in with a Vampire, which is why he took up teaching, wasn’t he?
Ah, pardon, it was Professor Quirrel, and it’s already been mentioned. :o