This will be a story between Anna and Van Helsing/Gabriel. It goes with the idea of what would happen if, right before she injected the cure, he gained control of his wolf nature. Maybe he doesn't need a cure. When he takes Anna and they go to the Vatican to explain what happened, they turn on him, because he was bitten by a Moon Child wolf. Where did the cure come from? Who are the Moon Child wolves? Soany questions, so little time before the next full moon.
If you are interested in seeing where this goes, review and/or message me. I'd like to expand my ideas as they hit me.