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Background:  Post-exposure prophylaxis (PEP) is offered following sexual assault (SA) in South Africa, but adherence and side effects have not been described in this setting.

Methods:  An observational cohort of subjects enrolled within 2 weeks of a SA involving potential HIV transmission. Those presenting within 72 hours are offered PEP. Adherence is assessed at 1 and 4 weeks. Subjects are followed for 6 months for symptoms, potential interim HIV exposure, and HIV seroconversion.

Results:  We enrolled 116 eligible subjects from March 2004 to September 2004; 113 were women. The median age is 20.5 (14 to 67) years. Eighty-four (72%) were African and 30 (26%) were “colored.” Vaginal penetration was reported by 95 (82%), anal penetration by 6 (5%), and vaginal penetration plus other exposure(s) by 15 (13%). Twenty-seven (23%) were assaulted by more than 1 perpetrator, and 11 (9%) subjects reported previous sex with the perpetrator for a median of 1.4 years (1 day to 8 years). Of the group, 114 (98%) of the subjects were eligible for, and105 (92%) received, PEP. Median time from the assault to PEP initiation was 24 hours (4 hours to 5 days). PEP was initiated within 24 hours by 42 (40%); 25 to 48 hours by 50 (48%); 49 to 72 hours by12 (11%), and after 72 hours by 1. Five subjects discontinued PEP prior to 28 days, and 23 (26%) of 87 subjects taking PEP at week 1 reported missing any doses in the prior 4 days. Of 49 subjects taking PEP at week 4, 3 (6%) reported missing any doses in the prior 4 days. Fift-nine (51%) of 116 subjects reported a ± grade 2 symptom at their initial visit. At week 1, 35 (36%) of 96 subjects reported a ± grade 2 symptom at week 1; 26 (32%) of 81 reported a ± grade 2 symptom at week 4. Unprotected intercourse since the last visit was reported by 42 (44%) at week 1, 20 (25%) at week 4, and (33%) at week 12. There was 1 HIV seroconversion at week 12 in a subject who reported excellent adherence and whose regular sexual partner’s HIV status is unknown.

Conclusions:  SA in this setting involves high-risk exposures and often multiple perpetrators. PEP is often available within 48 hours and is well-accepted. Few discontinue PEP, but a quarter report missed doses in the first week. Symptoms are common, although without a placebo or no-treatment control we cannot attribute them to PEP as opposed to trauma-associated distress. More intensive counseling and/or a shorter course regimen with few side effects may improve adherence. Counseling to minimize subsequent HIV exposure in this high-HIV prevalence context is critical.

Keywords: Post-exposure prophylaxis; Prevention; Sexual Assault