A needle covering system for a needle of a syringe. A boot of the system defines a contaminant-proof pocket for the needle. A sealing ring portion of the boot forms a seal with a support portion of the syringe. A body of the boot is collapsible to allow movement of a needle pierceable end portion of the boot toward the sealing ring portion for a tip of the needle to pass through the boot end portion for an injection. A securement collar of the system presses the sealing ring against the support portion of the syringe and is a remnant portion of a protective shell.