Wow, that's an interesting place. I'm think about this both as if I was DMing this party and as RAW as I can get, which sometimes don't line up.
The reduction in max HPs continues until a long rest. RAW, a dead character can't take a long rest. But then RAW there's a question if the object (body of the dead character) is a valid target anymore for the HP drain. (Note that the buried & rise portion does not say that the body must still be at 0 max HPs, just that it was slain via this method, so it gives no guidance.)
Long rest mentions sleep with the possibility of light activity for up to 2 hours of it. Dead you can't sleep so by RAW that doesn't qualify.
Greater Restoration, on the other hand, is very clear that it needs to target a creature, which the dead body does not qualify as. So there's no way to cast that. Remove curse does target a creature or object so it could target the body, but there is nothing in the wording of the Vampire's Bite defining this as a curse.
Both Raise Dead and Revivify specify that you have 1 HP. How that interacts with 0 max HPs is undefined in the game, but the common usage of "maximum" implies it doesn't work.
Raise Dead, Resurrection, and True Resurrection have lists of what could be affecting a corpse, including wounds/damage, poison, disease, curses, and "the like".
Okay, here's thoughts:
Most permissive RAW: There is nothing that states that your HPs can not go above your your HP maximum via non-healing means, so Revivify (and better) would work, though the character's HP max would still be 0 (which is only death in conjunction with the Vampire's bite). A Greater Restoration or long rest to remove that penalty would be STRONGLY recommended. As a DM, I don't like this because it takes the horror away on top of it begin ridiculously legalistic and ignoring common usage of words like "maximum".
Permissive DM: I could allow that when the time for a long rest has passed, the HP maximum reduction has expired and raising after that would work. This is making a ruling that the vampire bite isn't supposed to last for more than about 24 hours so it's a temporary thing. This would still rule out Revivify so it keeps the appropriate level of horror. I might rule this for some tables I've been at.
Moderate DM: Make the ruling that Remove Curse will work (since it can target an object and "curse" seems to fit the vampire myth concept) and/or Greater Restoration can target a dead body since it once/will be a creature. I would likely go rule here myself, it gives a reasonable out and keeps the horror of vampires. (Side note, I'd also allow a Remove Curse before a corpse is buried to prevent rising as a vampire, along the same vein.)
Extreme RAW: Long rests can't happen, it's not a curse, greater Restoration can't target an object. Find another way to do it. Might be a quest or True Resurrection.