Pre-filled safety needle and syringe system

A needle and pre-filled syringe system that provides ultra-low dosage waste and automatic needlestick protection. A syringe assembly is pre-filled with an injection material. A needle head assembly attaches to the syringe assembly. A spacer is disposed between the needle head assembly and the syringe assembly. The spacer has a central opening. The needle head assembly supports a needle with a needle base. When assembled, the needle base passed into the central opening of the spacer. The needle head assembly also contains a safety slide that can selectively cover the needle. During an injection, pressure and/or contact with the plunger head causes the spacer to contact and move the safety slide. The safety slide moves to cover the needle during the injection procedure, therein rendering the needle safe before the injection process is even complete.