Connector for connecting a medical injection device having a distal tip and a sleeve extending around the tip, the sleeve being provided with an inner threaded portion , to a container closed by a pierceable septum , said connector comprising: - a proximal part configured to sealingly engage the tip of the injection device , the proximal part comprising an outer threaded portion configured to be removably screwed to the inner threaded portion of the sleeve, - a distal part configured to be connected to the container , - a hollow spike extending distally from the proximal part , having an internal volume configured to be in fluidic connection with the injection device , the spike being configured to perforate the pierceable septum of the container when the distal part is connected to the container, the spike comprising an opening in a distal end, said opening being configured to create a fluidic connection between the medical injection device and the container , and - a sealing cap mounted on the hollow spike so as to sealingly enclose at least the opening of the hollow spike , the distal part comprising a skirt extending around the hollow spike , the skirt being adapted to enclose at least the collar of the container when connected to said container, the skirt comprising a flange , the sealing cap comprising a closed distal part , a proximal part provided with an opening , and a hollow body that extends from the opening towards the distal part, the hollow body being configured to sealingly engage the hollow spike , characterized in that the proximal part of the sealing cap is configured to be sealingly and at least partially inserted into a groove provided in the flange so that said proximal part of the sealing cap radially abuts an inner surface of the groove . - a proximal part configured to sealingly engage the tip of the injection device , the proximal part comprising an outer threaded portion configured to be removably screwed to the inner threaded portion of the sleeve, - a distal part configured to be connected to the container , - a hollow spike extending distally from the proximal part , having an internal volume configured to be in fluidic connection with the injection device , the spike being configured to perforate the pierceable septum of the container when the distal part is connected to the container, the spike comprising an opening in a distal end, said opening being configured to create a fluidic connection between the medical injection device and the container , and - a sealing cap mounted on the hollow spike so as to sealingly enclose at least the opening of the hollow spike , the distal part comprising a skirt extending around the hollow spike , the skirt being adapted to enclose at least the collar of the container when connected to said container, the skirt comprising a flange , the sealing cap comprising a closed distal part , a proximal part provided with an opening , and a hollow body that extends from the opening towards the distal part, the hollow body being configured to sealingly engage the hollow spike , characterized in that the proximal part of the sealing cap is configured to be sealingly and at least partially inserted into a groove provided in the flange so that said proximal part of the sealing cap radially abuts an inner surface of the groove . <EOS>