Nano Counter Phage, sometimes incorrectly described as “Nasser-Collins Procedure”, is a medical technique used to combat viral and bacterial infection.

In NCP, the patient is injected with a dose of nanomachines. These machines are equipped to recognise the specific infection agent being targeted, and destroy its cells. The NCP agent automatically self-deactivates after a period determined by the administering physician.

NCP agents are kept simple to reduce size and cost. They are custom-built on demand to target specific agents, and cannot reproduce or adapt. However, since they are immune to attack themselves, they are guaranteed to eventually clear any infection, provided a sample is available to train them to recognise.

NCP is not effective against malign growths or parasites. Custom surgical nanites can be made for those purposes, but they tend to be more expensive and require more hands-on guidance.

NCP agents share technology with the disposable repair nanites found in advanced field dressings, and the system later developed into the permanent nanomaintenance suites that were added to citizens' default personal implants by the 4700s. Although superficially similar, the SERENA (Self-Repair Nanotechnology) system carried by later models of Jiangshi is not closely related. SERENA agents are long-lived, networked, self-replicating, and primarily used for reconstruction rather than hunter-killer activities (although they can be modified to combat nanowarfare infections).