Are their any vampire witnesses or vampires still alive?

There never were any vampires in the sense of supernatural immortal undead creatures, so no.

There have been some pretty disturb[ed|ing] people who behave in much the same way that the mythical vampires do (either because they're mentally ill and really believe themselves to be vampires, or because they just think it "sounds cool"), though, and undoubtedly some of them are still alive.