Another one based on parasites just occurred to me. An Apple of Knowledge hack that makes the non-fit infected more attracted to and interested in people with high intelligence and status, while making those infected obsessed with Titans and wanting to go to active Titan sites/quarantine zones and have their behavior and risk evaluation shifted. So you have mostly asymptomatic carriers and the targets, the people with high mental abilities and in positions of power basically offer themselves up on a platter for forced uploading.
This reminds me on a TITAN nanovirus I came up with, formally referred to as Lethe but nicknamed Brain Drain. It worked on the principle of brain fingerprinting (
https://en.wikipedia.org/wiki/Brain_fingerprinting) which, to grossly oversimplify, allows you to tell what someone does or doesn't know by seeing if their brain gives the "nope, no need to remember this stuff; we already know it" signal when it receives certain data. So, if only the murderer would recognise the murder weapon, you could literally look at a suspect's brain and go "he knows that weapon; therefore he's the murderer". (Well, again over-simplifying - it doesn't know WHY the information is in the brain, just that it is there. So a detective would recognise the murder weapon and wouldn't be the murderer. But you get the point.)
How this translated to Lethe/Brain Drain was a way the TITANs subverted the R&D efforts against them. Essentially it was a culling of the most intelligent and technically training egos, especially in the field of nanotechnology. It jacked into your nervous system, tapped into your sensory feeds and waited. It still exists in 10 AF because of this very long latency period; it's possible for someone infected to never turn symptomatic. It triggered when the host was processing and understanding advanced technical data, eroding the walls of blood vessels in the brain to cause a cerebral haemorrhage. In true Lovecraftian (and Calebian) fashion, the most reliable way to trigger it was to learn you were infected and understand exactly what that meant; by understanding why you were doomed, you doomed yourself. It was most deadly against the people most likely to be able to fight it.
(I hope that mild anecdote is permitted if you consider my bringing up of brain fingerprinting as fodder to the thread)