Seroconversion following nonoccupational PEP against HIV

University of California, San Francisco, San Francisco, California, United States
Clinical Infectious Diseases (Impact Factor: 8.89). 12/2005; 41(10):1507-13. DOI: 10.1086/497268
Source: PubMed


The efficacy of antiretroviral postexposure prophylaxis (PEP) against infection with human immunodeficiency virus (HIV) following occupational exposures has prompted the use of PEP after nonoccupational exposures. There are, however, important differences between occupational and nonoccupational exposures, and the effectiveness of PEP following nonoccupational exposure is unknown. We sought to describe the occurrence and circumstances of HIV seroconversion following nonoccupational PEP.
HIV uninfected individuals reporting potential sexual or injection drug use exposures to HIV in the preceding 72 h received a 28-day regimen of antiretroviral therapy and counseling in a nonrandomized trial. The level of HIV antibody was measured 12 weeks after PEP initiation.
Of 877 exposed subjects, 702 were evaluable 12 weeks after exposure. Seroconversion was detected in 7 subjects (1%; 95% confidence interval, 0.4%-2%). Three seroconverters reported having no exposures after PEP initiation and, thus, probably represent evidence of chemoprophylactic failure. In the other 4 subjects, additional exposures to HIV after PEP initiation or detection of HIV RNA in plasma specimens obtained at baseline precluded determination of the source of seroconversion. No exposure source was available to assess genetic concordance with the seroconverter's virus.
As for occupational exposure, PEP is not completely effective in preventing HIV infection following nonoccupational exposure. Therefore, primary prevention remains essential. In contrast to the occupational setting, the potential source of exposure is rarely available for testing in the nonoccupational setting, and exposures are often not isolated. Thus, it is often impossible to determine whether seroconversion resulted from failure of PEP or from other exposures, posing difficulties for future comparative studies seeking to evaluate the effectiveness of PEP.

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    • "Following extensive public and political debate, the South African Government adopted a policy in 2002 to provide anti-retroviral medication to prevent HIV transmission as part of comprehensive post-sexual assault care (South African Department of Health, 2005). There is no direct evidence of the efficacy of post-exposure prophylaxis (PEP) for sexual exposure, but studies on animals, on occupational exposures and prevention of mother-to-child transmission suggest that PEP is highly effective if commenced within 72 hours of exposure and 28 days of uninterrupted prophylaxis are completed (Roland et al., 2005). Based on this research, South Africa adopted the use of dual therapy with both Lamivudine and Zidovudine, and in some provinces triple therapy is given with inclusion of Kaletra for ''high risk'' cases. "
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