RT Journal A1 Jochimsen EM, Luo C, Beltrami JF, Respess RA, Schable CA, Cardo DM T1 INvestigations of possible failures of postexposure prophylaxis following occupational exposures to human immunodeficiency virus JF Archives of Internal Medicine JO Archives of Internal Medicine YR 1999 FD October 1 VO 159 IS 19 SP 2361 OP 2363 DO 10.1001/archinte.159.19.2361 UL http://dx.doi.org/10.1001/archinte.159.19.2361 AB Although evidence suggests that PEP may be effective,3 failures of PEP with zidovudine have been reported.4- 5 It is likely that failures of PEP with combination therapy also will occur, and one possible case has recently been described.6 Since little is known about the effectiveness of PEP for occupational HIV exposures, investigation of cases of possible PEP failure can provide important information about factors that may influence PEP efficacy and occupational HIV transmission. Reports of PEP failure may help direct future epidemiologic or laboratory studies in this area and potentially could influence recommendations for management of occupational HIV exposures.