Blood Oath, by Christopher Farnsworth. Unabridged audio.
I read political thrillers. I read vampire novels. Why would I not read a novel that combines those two aspects?
Nathaniel Cade is a special assistant to the President, a position he has held for a century and a half -- because he is a vampire. He is forced by a blood oath to obey the current President and his specific designee. In this case, that designee is Zach Barrows, who has taken over those duties from former FBI agent William Griffin.
Throw in Dr. Frankenstein, Zombies, and the quest for eternal youth, and you have the outlines of the plot of Blood Oath. There are factions within the President's administration who don't want Cade & Zach to stop the zombies, and who may even be trying to kill the two of them. This worries Zach a lot more than it does Cade, as he is much more killable than the vampire.
Rarely do I read a book just because of the premise, but this one was so compelling -- a vampire on the President's staff -- that I did pick it up on a whim. And I'm glad I did; it moved along quickly, the main characters were developed well, the horror elements were unsettling.
The story here is completed in the main part of the narrative, although an epilogue makes it clear that a sequel is in the works. I worry a bit about that, as there seemed to be a lot thrown into this adventure, and I wonder what is left for Cade to face in further stories, but I will be there to find out.