A disinfecting cap comprising a housing, a protrusion and a cap cover (100, 200, 300), the housing comprising a top wall, an essentially cylindrical sidewall forming a first cavity, and an open bottom end opposite the top wall formed by the cylindrical sidewall with an opening (27, 114, 214, 314) to the first cavity within the housing for receiving a hub (72, 82) of a female needleless connector or a male needleless connector, wherein the protrusion is positioned within the first cavity and comprises an inner surface (21, 25, 31), an outer surface and an end that is distal the top wall of the housing, the inner surface (21, 25, 31) of the protrusion defining a second cavity, and wherein the outer surface of the protrusion and an inner surface (21, 25, 31) of the essentially cylindrical sidewall define a gap therebetween, and the cap cover (100, 200, 300) is dimensioned and positioned to cover at least a portion of the gap (28a, 35) between the outer surface of the protrusion and the inner surface (21, 25, 31) of the housing, characterized in that the cap cover (100, 200, 300) comprises a body (102, 202, 302) comprising a top surface (39, 108, 208, 308), an opposite bottom surface, an exterior wall (106, 206, 306) and an interior wall (104, 204, 304) defining an opening (27, 114, 214, 314), wherein at least a portion of the exterior wall (106, 206, 306) of the cap cover (100, 200, 300) is coupled or directly coupled to the inner surface (21, 25, 31) of the housing and the cap cover (100, 200, 300) interior wall (104, 204, 304) is positioned proximal to, adjacent to, directly adjacent to or abuts the outer surface of the protrusion such that the cap cover (100, 200, 300) is free to deflect downward into the gap (28a, 35) between the outer surface of the protrusion and the inner surface (21, 25, 31) of the housing upon insertion of a male connector into the disinfecting cap, or wherein at least a portion of the interior wall (104, 204, 304) is coupled or directly coupled to the protrusion outer surface and/or protrusion end (23, 37) and the cap cover (100, 200, 300) exterior wall (106, 206, 306) is positioned proximal to, adjacent to, directly adjacent to or abuts the inner surface (21, 25, 31) of the housing such that the cap cover (100, 200, 300) is free to deflect downward into the gap (28a, 35) between the outer surface of the protrusion and the inner surface (21, 25, 31) of the housing upon insertion of a male connector into the disinfecting cap, wherein the cap cover (100, 200, 300) comprises a resilient material, wherein upon detachment of the male connector from the cap, the cap cover returns to its original position. of the housing, the inner surface (21, 25, 31) of the protrusion defining a second cavity, and wherein the outer surface of the protrusion and an inner surface (21, 25, 31) of the essentially cylindrical sidewall define a gap therebetween, and the cap cover (100, 200, 300) is dimensioned and positioned to cover at least a portion of the gap (28a, 35) between the outer surface of the protrusion and the inner surface (21, 25, 31) of the housing, characterized in that the cap cover (100, 200, 300) comprises a body (102, 202, 302) comprising a top surface (39, 108, 208, 308), an opposite bottom surface, an exterior wall (106, 206, 306) and an interior wall (104, 204, 304) defining an opening (27, 114, 214, 314), wherein at least a portion of the exterior wall (106, 206, 306) of the cap cover (100, 200, 300) is coupled or directly coupled to the inner surface (21, 25, 31) of the housing and the cap cover (100, 200, 300) interior wall (104, 204, 304) is positioned proximal to, adjacent to, directly adjacent to or abuts the outer surface of the protrusion such that the cap cover (100, 200, 300) is free to deflect downward into the gap (28a, 35) between the outer surface of the protrusion and the inner surface (21, 25, 31) of the housing upon insertion of a male connector into the disinfecting cap, or wherein at least a portion of the interior wall (104, 204, 304) is coupled or directly coupled to the protrusion outer surface and/or protrusion end (23, 37) and the cap cover (100, 200, 300) exterior wall (106, 206, 306) is positioned proximal to, adjacent to, directly adjacent to or abuts the inner surface (21, 25, 31) of the housing such that the cap cover (100, 200, 300) is free to deflect downward into the gap (28a, 35) between the outer surface of the protrusion and the inner surface (21, 25, 31) of the housing upon insertion of a male connector into the disinfecting cap, wherein the cap cover (100, 200, 300) comprises a resilient material, wherein upon detachment of the male connector from the cap, the cap cover returns to its original position.