I know contraception is covered in the Edge books, but what about preventing other, less savory things?
The Storms that wrecked the world are far in our future but are hundreds of years in the raiders’ past. And a lot of things happened to the world – and in civilization in general – before the Storms hit. Not to mention during their span of terror and mayhem. Advances in science and technology in a bid to stop what was happening, attempts to change the deadly course of the Storms; anything and everything to try to minimize or reverse all that destruction. During this period of doomed advancement, all sorts of diseases were severely limited or eradicated entirely. That means that after the Storms destroyed everything and so much of the population was diminished, STDs aren’t really a factor.
Short version: the folks in the pages of the Edge books are free of disease and can confine their concerns to, you know, living through the long, hot, delicious nights. If they’re lucky.