A passive needle safety device for protecting the needle of an injection syringe after medication has been delivered to a patient comprising a body that can hold a syringe, a telescoping guard fitting over the body, and a spring deployed between the guard and body such that the guard is urged in an extend configuration distally relative to the body, the improvement comprising, trigger fingers for holding the guard and body together in an un-extended configuration against the force of the spring, and a plunger rod with a plunger head which pushes against the trigger fingers, the head having an angled surface that provides a lateral component of force to the trigger fingers to displace them from the latched configuration to an unlatched configuration.