An injector includes a housing, a needle hub movably mounted within the housing and an injection needle supported by the hub. The hub and the needle are axially translatable between retracted and injection positions. A needle shield, having an aperture, is movably connected to the housing between first and second positions. The needle extends through the needle shield aperture in the injection position of the needle and the first position of the needle shield, and the needle is blocked from extending through the needle shield aperture in the second position of the needle shield. When the needle shield is in the second position and the hub and the needle are in the injection position, the needle shield covers the tip of the needle and subsequent movement of the needle shield toward the first position axially translates the hub and the needle back toward the retracted position.