It was definitely Under the Eye of God.
Thanks again to vicki_girl and everyone else who suggested books! Oh, my TBR pile...

@vicki_girl I think David Gerrold is it! I think I may have only read the second one and missed the start of the series. Thanks! And thanks to everyone for the great recommendations! I'm going to go read some vampire sci-fi -- it'll be like middle school all over again.

Kathryn wrote: "TAS focuses more on computers, computer viruses, and a crazy girl. There are mutated humans, but the only ones that are described in detail are basically autistic (though that term is never used).
"

Actually they're not just autistic. Each of the various types in that culture represent a different type of what we consider mental disorders. It just happens that the iru are very similar to autistic savants. Good book, I highly recommend it.

I can also verify it isn't anything else by Friedman or anything from Asaro's Skolian Empire series.

There's Vampire Apocalypse A World Torn Asunder but I think it was published too late.

There is also a series of books (or multiple series) by Brian Lumley. Poking through the descriptions it they sound like they have a lot of the elements you mentioned (like twin brothers in Vampire World I Blood Brothers) and published around the correct time frame.

Could it be the following duology by David Gerrold?

Under the Eye of God
A Covenant of Justice

The second book is what caught my attention as possibly matching your descriptions.

M— wrote: "This Alien Shore is fantastic, was published in the 90s, has a full cast of differently mutated humans in outer space with inter-group conflict (the dominate group headed by a female, too), but I do not directly recall vampires."

From Miriam's description, it is definitely not This Alien Shore. I've read that a few times, and it has no vampires or suggestion of vampires (though the rest of C.S. Friedman's works are absolutely inundated with vampires which might be why it seemed a likely culprit). TAS focuses more on computers, computer viruses, and a crazy girl. There are mutated humans, but the only ones that are described in detail are basically autistic (though that term is never used).

Books, yay! I don't think it was any of those, but they all look good and are going on my list. Thanks!

GAH! Teh internets ate my long response. Suffice it to say that House of Zeor, the first book in the wonderful Sime/Gen series, is not a match to what the OP described.

But you should read it anyway. ;D

Hee! I've been flexing my google skills in trying to find likely books for you, and I found a comment of yours from another GR thread that seems to have been the genesis for your search for this title.

But. Blindsight probably isn't it; it's only very recently published. The Hunger kicks off a series of mutated/evolved vampires, but I don't recall any spaceship elements. This Alien Shore is fantastic, was published in the 90s, has a full cast of differently mutated humans in outer space with inter-group conflict (the dominate group headed by a female, too), but I do not directly recall vampires. Maybe the House of Zeor, although it published in the 70s?

Definitely no illustrations, and I don't think they were meant for a YA audience.

Diana wrote: "Yeah, I realized that the OP would probably remember if they were graphic novels, too. I edited my post."

I don't think they were graphic novels or manga, just young adult (light) novels, but there were some illustrations in them and you are right, those illustrations would probably have been memorable.

Definitely not Benighted -- it had no werewolves. It was pretty much a sci-fi "future with spaceships interstellar battles" type of setting, only with the vampire twist.

Yeah, I realized that the OP would probably remember if they were graphic novels, too. I edited my post.

The Kikuchi (Vampire Hunter D) light novels were first published in the 1980s, but English translations of them were not officially released until 2005. Neither date matches well with when the OP read her book.

Sounds like Benighted by Kit Whitfield, but that's werewolves.

No, those were actual aliens, and V was set in the present.

Sounds a little like the movie 'V' to me...

It was definitely not The Madness Season. There were lots of vampires, led by a queen (or queens). There may have been aliens, but the vampires were the dominant power. I don't think it was the Ruby Dynasty either, as I don't recall anything about psions or any complicated class systems. And it sounds like there was a lot about sex and breeding, which I don't think there was in the book I'm looking for. But I will try to find a copy to be absolutely certain.

Alycia wrote: "Were they actually called 'vampires'? I can think of several series which have this theme, but the genetically engineered race were not referred to as vampires."

I had a similar thought. The two stories that came immediately to my mind was The Madness Season, a standalone scifi featuring vampires as alien invaders, and Catherine Asaro's Ruby Dynasty series, which has a group of 'psychic vampires' as the main antagonists (who were related to the main protagonists, sometimes, depending on which book you read).

There is a wiki write-up on Asaro's psychic vampires.

It is definitely older than Fledgling. It takes place in the future, in outer space, and I think there were at least 2 books. I don't remember any kids in it. There were two adult brothers who I think were the main characters in at least one book. I believe the normal people did refer to them as vampires (maybe as a slur?). And I vaguely recall that maybe they were poisonous? Like, once you had your blood drunk by them you got sick?

Were they actually called 'vampires'? I can think of several series which have this theme, but the genetically engineered race were not referred to as vampires.

I thought Fledgling by Octavia Butler. But that was published in 2007. Hmm...

Recently someone recommended E.E. Knight's Vampire Earth series to me, and it reminded me of a science fiction series I read years ago (probably early 90s) where humanity creates a genetically engineered group that are essentially vampires (I think it was to fight or work in outer space) and eventually they use their superior strength etc to take control and regular humans become their slaves. Some humans remain free and try to resist vampire hegemony.