All communications between the individual defendant and any person in or engaged by the Public Defender shall be fully protected by the attorney-client privilege to the same extent and degree as though counsel had been privately engaged. This in no way precludes the use by the Public Defender of material in his files, otherwise privileged, for the preparation and disclosure of statistical, case study, and other sociological data provided always that in any such use there shall be no disclosure of the identity of particular defendants.