A while back I saw the film Day Breakers:
If you're not familiar with this film, it's about a future world where bats have attacked people and spread the plague of vampirism across the human race. In an attempt to determine a viable substitute for human blood, the main character comes across a man who was a vampire but has turned back to human. They attempt to recreate his experiment (a crazy sunlight on the chest event) but ultimately *SPOILER ALERT* find out that the blood of a human turned vampire turned human is a antidote to vampirism. The good thing about this, minus the human turned vampire turned human casualties, this antidote spreads faster and is less risky than the sun experiment.
I did wonder though, since the movie essentially ends with a huge massacre where starving vampires attack the human turned vampire turned human characters, and as the first wave of people turn human from ingesting the blood, they, in turn, are attacked and consumed. This leaves a room full of dead humans, like 50-60 dead humans, all of who are carrying the antidote.
Now, if the characters who survive, take these dead humans with the antidote and toss them into the subway where a lot of starving vamps are hanging out, will this spread the antidote or create a new type of creature, a zombie? If the blood turns them human, but its the blood from a dead human, would they then become a dead human? If that's the case, they could create a sequel called "Death Breakers":
I think it's also interesting to note that as the vampires were starving, they began to resemble bats, as their bodies morphed into bald, superhuman creatures with pseudo wings. Now I know what your thinking, Batmen? Do you mean Batman? To clarify, I made this picture:
Also, I'm really enjoyed Willem Dafoe's performance as the human turned vampire turned human named Elvis, but there always is a small part of me that thinks back on his performance in Boondock Saints and wonders if he would have been better in this film as a woman. To clarify which Willem was in this film, I made myself this picture, which I did bring to the theater just so I wouldn't get confused:
Overall, the premise is thought provoking, the film is dark and dramatic, the storyline is lacking in some ways but is a good conversation starter (primarily based in the "I could do it better and here's how" conversations which sometimes lead to more interesting and satisfying stories from writers who watch the film) and lastly the screeching bat that flies at the screen at the end of the film reminds viewers that this movie is, in fact, a comedy.