Memorandum from Alan Harvey to Stephen Waring, cc P. Macnaught, PS/PS, J. Orr, APS/PS(H), H. Causley, PS/CMO, R. Dickson, PS/CMO, N. Raisen, PS/DCMO, Dr A. Wight, inter alia, Re Risk assessment for transmission of vCJD via surgical procedures, inter alia