Tangential: this reminds me of the intentional infection with disease / virus in one of the Takeshi Kovacs novels (Woken Furies, I think), in which one characte

Tangential: this reminds me of the intentional infection with disease / virus in one of the Takeshi Kovacs novels (Woken Furies, I think), in which one character deliberately maintains a level of infection due to the body's reaction to the infection being a net positive in regards to <something I can't remember>, and there being mention of the fact that they know it's unsustainable, but want to ride it as long as their body is able. Something along the lines of increasing the body's core temperature in order to be able to deal better surfing in colder water. Designer viruses to get a specifically desired symptom. Interesting concept.