The movie lacks any explicit showing of siring, the creation of a vampire. All we see is biting. The vamps at the beginning were bit on the plane before it crashed, and the Second Bride, the Reporter Solina afterwards. Lucy the Third Bride, is also shown just being bit.
Solina makes a vague reference to being chosen (as a lover) while she is in an interrogation room at a police station. Soon after, she breaks through and the movie implies she feeds on the Detective, while Dracula feeds on the Doctor. We don't see either of those two, or if anyone else in the police station who may have been killed, turned into vamps later in the movie. We also see that Prof. Van Helsing was killed, supposedly drained by the 3 Brides, but he also remains dead. Nor do we see the cameraman that Dracula attacks before he turned Solina.
The closest thing we see is the dream sequence/flashback when Dracula turns Mary and shows her how he was created. After biting her in the real world, she also drinks his blood in the dream sequence. Given that we are then shown a flashback to Dracula's disciple days, can't be sure if it is required for turning into a vampire or just the flashback or if it even happened in the real world.
So conclusively, the only thing that was shown is that Dracula bit them, and some turned while others might not have (or were completely ignored afterwards), and it might have to be a conscious choosing on Dracula's part on who turns.
One possible clue is that in the end, Dracula releases Mary of her vampirism.
I guhgrr release gurchoakingnoises you.
*Mary's pupils go from blood red, to white, to normal*
He had magical control over her vampirism and could release it by will alone, indicates that turning people into vampires could also be purely done by choice.
Dracula, as written by Bram Stoker, required multiple days (nights) of feeding on Lucy before she was turned, so it cannot be used as a base reference.
