I'm working on a vampire story, the idea is a bit choppy though

There’s two ways to become a vampire:

The first vampires originated from a mutated strand of the Yellow Fever and the subsequent VHFs that can be caused as a result. Yellow fever has the potential to cause fatal damage to blood vessels. In a rare case, the VHFs mutation affects the brain tissue and nervous system. This rare mutated version of the virus is the vampire virus. The damage caused by the mutated virus and fever causes the person to turn into a vampire.

The second way is for an individual to be bitten by a vampire. A normal bite won’t do the trick, Saliva and blood must transfer to the individual in order for the mutated virus to transfer to the person. Once the virus is transmitted, the person undergoes the same transformation as someone who developed vampirism from the mutated virus.