First, the drawbacks. The design limits the nanites in several substantial ways. The new generation of nanites cannot reproduce. The programming is deliberately missing, and the nanite operates as an isolated unit, motivated by a simple pilot program, one of thousands in any given application of units. Basic pack guidance protocols eliminate redundancy, allowing a nanite to move on to another zone of activity if it sees the one it goes for is already cared for. Without a wireless connection to coordinate and guide them, the nanites are essentially free-roaming drones in the body. They depend entirely on chemical markers and preprogrammed guidance protocols to do their jobs, cut off from all but a chemical trigger to harmlessly self-terminate. Each acts as an individual, blind to anything its sensors cannot detect. This means it cannot spread or maintain function for any signifcant amount of time, which, while saving the user from the risk of CFD, also means the nanites are unable to self-sustain or adapt. It also means the nanite is less sophisticated than in the past. Its program follows a strict, linear dynamic, incapable of fuzzy logic and unable to escape its very particular function.
In terms of practical applications, this makes a repair nanite impossible, whether for technological or medical uses. Mender nanites, universal nantidote, and the much-hoped-for hunter-killer anti-nanite, all require complex diagnostic data and interactivity, medical interface, and coordination to be effective. As a CFD vaccine, the new nanites can’t keep up with the self-evolving, reinforcing, coordinated defense of the infected breeds. Similarly, the bacteria used to cleanse a system is an early-stage prototype for a CFD vaccine, but it is currently unable to sustain the effect on a rapidly adapting nanite population like those found in head cases.