HTLV-III infection among health care workers. Association with needle-stick injuries.

Health care workers are caring for an increasing number of persons infected with human T-cell lymphotropic virus type III (HTLV-III), the primary etiologic agent of the acquired immunodeficiency syndrome (AIDS). We studied 361 health care and clinical laboratory personnel from institutions in several metropolitan areas with both high and moderate levels of HTLV-III infection among high-risk group members to evaluate routes of exposure to and seropositivity for HTLV-III. Protection of the privacy of subjects and prospective determination of risk factors were integral components of the study design. Six (26%) of 23 health care workers with recognized risk factors for AIDS had HTLV-III antibodies. Thirty-nine (14%) of 278 workers at one institution as well as a total of five workers from other institutions reported possible percutaneous exposure to HTLV-III, usually injuries with needles that had been used on AIDS patients. There were three HTLV-III seropositive subjects who reported possible parenteral exposure to HTLV-III but no recognized AIDS risk factors. One was a symptomatic female, subject A, and her apparent sources of HTLV-III exposure were two puncture wounds, without injection of blood, made with needles used on AIDS patients. Human T-cell lymphotropic virus type III was cultured from her asymptomatic, seronegative long-term sexual partner, apparently representing female-to-male transmission. For the two other seropositive workers (subjects B and C) with nosocomial parenteral exposure, we could not rule out heterosexual transmission as a possible source of HTLV-III exposure. These latter two cases as well as the identification of seropositive health care providers from known risk groups point to the need for thorough case investigation to identify routes of exposure in health care workers. The risk of nosocomial HTLV-III transmission appears to be low and related to percutaneous exposure. Medical personnel should be trained systematically in the proper techniques and handling of instruments for phlebotomy and similar procedures to decrease occupational exposure to HTLV-III.