A needle assembly that has a flexible shield movable between (i) a first position, where the flexible shield is uncompressed, and (ii) a second position, where the flexible shield is compressed and an administering member located within the flexible shield, where at least one of the administering member and the flexible shield is axially movable with respect to the other of the administering member and the flexible shield in an unlocked position prior to and during usage of the needle assembly, and the at least one of the administering member and the flexible shield is no longer axially movable with respect to the other of the administering member and the flexible shield in a locked position. Prior, during and after use of the needle assembly, the needle is never exposed. After a single usage of the needle assembly, the needle is locked within the flexible shield and cannot be reused.
