Abstract: The invention relates to a shield (1) for covering at least part of a needle (2) and needle hub (6) of a needle assembly, said shield (1) having an open proximal end (1a), a closed distal end (1b) and a longitudinal wall (4) extending from said proximal end (1a) to said distal end (1b) and defining an interior cavity (5) for receiving at least part of the needle (2) and needle hub (6), characterized in that it comprises at least a first retainer (9) defined on said wall (4) and extending into said cavity (5) and, at least one second retainer (8) defined on said wall (4) and extending into said cavity (5), said annular bead portion (9) and second retainer (8) being designed to be able to, resiliently and releasably, engage a part of said needle assembly to secure said shield (3) thereto, said first retainer (9) and second retainer (8) having at least their shape or one of their dimensions different from the other.