Most injuries accounted for in the Dead and Back combat system are ones that (usually literally) take a chunk out of someone - enough to impair their ability to keep running. However, not all injuries in life are those that will permanently cripple a person. Fortunately, only a very few do that.
One of the easier ways to model relatively minor injury, is to apply the same impairment as when low on fatigue or lucidity - die rolls use only six as the target number. At the Game Master's discretion, this is further limited to only problems where the pain might come into issue. A hurt hand doesn't impair thinking, an injured leg has little to do with aim and sense of direction.
Standard Nano Vaccine does not protect against chemical hazards. A specialized form of the stuff can remove toxins, but can't actually prevent them from acting. For one, it can't act fast enough (generally the micro robots need an outside way of identifying the toxin) and often blocking a chemical entirely is problematic, since a great deal of poisons are analogs for internal chemistry. Blocking a neurotoxin, for example, would probably end up with the nano affecting the hormones that are supposed to be acting on the receptors as well. Internal surgeons do at least mitigate the damage and speed up recovery.
As with minor injuries, many chemical effects can be modeled by either role-play or assigning higher difficulties to tasks.