If you've contracted Sanguine Vampiris, you can cure it like any disease - either with a potion, by visiting a shrine, or asking a vigilant of Stendarr. If you've let the disease progress to full-blown vampirism, however, you'll have to go through the quest Rising at Dawn to cure yourself.
There's currently no way to cure any NPC of vampirism apart from Serana, because it's also impossible for an NPC to even contract it in the first place (from other NPCs; the player can turn companions if they wish). Any vampires you run into are spawned as such, and can't be "cured". There might be a vampire removal mod of some kind, or one that replaces vampires with something else in much the same way some of the arachnophobe-friendly mods have done for spiders; but I haven't looked for one.
Edited by Hyacathusarullistad, 28 November 2014 - 05:42 PM.