Feasibility of Postexposure Prophylaxis (PEP) Against Human Immunodeficiency Virus Infection After Sexual or Injection Drug Use Exposure: The San Francisco PEP Study [Kahn JO, et al. JID 2001;183:707]: This is the report from the San Francisco PEP Study for non-occupational HIV exposure. The criteria for treatment include the following: exposure within 72 hours, age >13 years, informed consent, anal or vaginal intercourse without a condom or a failed condom, receptive oral intercourse, sharing of IDU equipment, or "other activities that resulted in exposure of blood or genital fluids on a mucous membrane or broken skin." The source had to have known HIV infection or be in a high-risk category, including gay men, IDUs, commercial sex workers or an anonymous source. This report concerns the analysis of 401 participants; 375 (94%) were sexual exposures. The median time from exposure to treatment was 33 hours. Antiviral drugs consisted of two NRTIs for 97%; the most common was AZT plus 3TC for 351 of 397 (86%) who chose to be treated. With regard to the source, 43% reported a partner who was known to have HIV infection and 57% were uncertain. Of the 397 who elected to receive antiretroviral treatment, 309 (78%) completed the four-week course. Toxicity reported by these participants included nausea in 52%, fatigue in 44%, headache in 24%, diarrhea in 15%, and anorexia in 12%. Monitoring of laboratory tests showed essentially no important complications. None of the participants seroconverted.
Comment: This is an important study because it addresses an issue that is confronted by virtually all HIV care providers. The investigators have demonstrated the feasibility of PEP for non-occupational HIV exposures. The decision to use two NRTIs rather than HAART is arbitrary. The fact that there were no transmissions is not conclusive. The report from Uganda by Ron Gray at the 8th CROI indicated an average of 560 sexual exposures for one transmission [8th CROI, 2001, Chicago, Abstract 266]. This report includes about 400 patients with 57% having uncertain HIV status, and many of the others presumably receiving antiretroviral agents that would presumably reduce risk of transmission. A limitation in the practical application of this experience is the support that is provided, which was listed as NIAID, CFAR, University of California University-Wide AIDS Research Program, the W. McCarty-Cooper Trust, and four drug companies. Most will not have this kind of support and may find great difficulty in getting the resources to do this. Nevertheless, this experience will be viewed as important information for dealing with the issue even if it will be difficult to match the resources.
posted 3/29/2001

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