The vacc shot is basically a super-vitamin. It gives a substantial increase to your (hidden) Health stat, meaning that you’re pretty much set against getting a Cold or Flu (the ambient diseases) for a while. Since your Health trends to 0 (middling), it’ll wear off in time.
The infection you get from zed bites is a mundane infected-wound. Everyone’s got the reanimate-on-death disease already.
