The Vampire Plagues: London, Paris and Mexico by Sebastian Rook: young adult trilogy published by Scholastic. The writing is my own, the plot is someone else’s, hence the nom de plume.
The Vampire Plagues have already — and strangely — inspired some slash art. If you know what slash is in respect to science fiction writing, you might raise an eyebrow and may or may not want to click here, here and here. If you don’t know what slash is, give thanks for your ignorance.