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Postexposure Prophylaxis for HIV After Sexual Assault

Administration is feasible, but loss-to-follow-up rates are high, and completion rates are low.

Postexposure prophylaxis (PEP) for HIV is recommended by international, national, and state guidelines, but implementation among sexual assault survivors is challenging. To better identify and characterize barriers to service delivery, investigators conducted a protocol-driven pilot program at 18 sexual-assault treatment facilities in Ontario, Canada. The program was free to patients and involved risk assessment, PEP recommendation (based on source characteristics and exposure type), medication provision, and intensive medical follow-up.

From September 2003 through January 2005, 1103 individuals (97% women) were evaluated for PEP eligibility after sexual assault. The 121 who presented 72 hours after assault were excluded, as were the 81 who were determined to have "no" risk for HIV acquisition. Of the subjects who were at "high" risk (71) or unknown risk (829), 798 were offered AZT/3TC plus lopinavir/ritonavir for 28 days; 347 (43%) accepted, and, of these, 111 (32%) completed the full course of treatment.

Adverse events accounted for 81% of the discontinuations for which explanations were available. Most PEP recipients (96%) reported at least one adverse event of any grade; 77% reported at least one event of grade 2 to 4 severity. Notably, adverse event rates did not differ between those who completed PEP and those who did not. Interestingly, no blood dyscrasias were reported.

Comment: PEP is receiving increased attention as a biomedical HIV prevention strategy at a time when vaccines and microbicides have proven disappointing. This important prospective cohort study highlights some of the key issues associated with PEP delivery. First, completion of the 28-day treatment course is likely paramount to efficacy but remains a major challenge. Adverse events have often been thought to cause discontinuations, but this idea has limited support in the data. Second, the context of sexual assault and its attendant traumatic nature complicates the emotional milieu for service delivery and underscore the need for PEP medication administration to be integrated into a program of tailored services, in this case, involving rape crisis specialists, longitudinal mental health linkages, and intensive adherence support services. Third, the cost-effectiveness of PEP is exquisitely sensitive to the source individual’s risk status. In this study, as is often the case clinically, most sources were of unknown serostatus; offering PEP to these patients is unlikely to be cost-effective. However, calculating an individual’s risk in this situation is extremely difficult, given the many unknown variables, and an incorrect determination could have serious consequences. Finally, the wisdom of using three-drug regimens in all cases, as was done here, is questionable; such regimens are more expensive and more toxic than two-drug PEP regimens and offer no documented incremental benefit in prevention efficacy.

— Raphael J. Landovitz, MD

Dr. Landovitz is an Assistant Professor in the Division of Infectious Diseases, Center for Clinical AIDS Research and Education, at the University of California, Los Angeles.

Published in AIDS Clinical Care March 17, 2008

Citation(s):

Loutfy MR et al. Prospective cohort study of HIV post-exposure prophylaxis for sexual assault survivors. Antivir Ther 2008; 13:87.

• Medline abstract (Free)