A needle protection device for use with a vial that contains medicament to be used with applicators such as the TUBEX and CARPUJECT applicators is disclosed in the aforenoted related '819 application. One embodiment of the related device disclosed in the '819 application has a collar that slidably fits over the hub of a vial and secures thereto by means of a number of extending fingers. Another embodiment of the '819 device has an open collar that mounts about the vial. A pair of interlocking extensions from the collar coact to secure the collar about the vial. Although work well, these devices fail to take full advantage of the structure of the vial itself and the interaction between the vial and the applicator in order to securely couple the needle protection device to the vial.