Apart from the old vampire.combat.contract that prevents players to get infected when fighting a vampire, two more permission nodes have been added.
On the one hand, we now have vampire.trade.contract, that prevents a player from becoming infected when trading blood with a vampire.
On the other hand, the vampire.flask.contract node has been added, that prevents a player from becoming infected when drinking a flask containing the blood of a vampire.

Suggested by Monipo82