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HIV post-exposure prophylaxis after sexual assault
  1. J Crossley
  1. Correspondence to:
 Dr J Crossley
 Sheffield Children’s Hospital, Western Bank, Sheffield S10 3TA, UK;

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The decision for HIV post-exposure prophylaxis after sexual assault should be considered on an individual basis

Merchant and colleagues report an audit of adherence in their paediatric emergency department to the New York State Department of Health guidelines on HIV post-exposure prophylaxis (PEP).1 The guidelines recommend that every victim of unprotected vaginal or anal rape presenting within 36 hours should receive HIV PEP unless the assailant is known to be HIV negative. Where possible, they should receive treatment within one hour of assault. Over six months, 14 of 25 patients received HIV PEP. No patient presented within one hour. Even after presentation, the minimum triage to medication time was two hours. The authors suggest strategies to speed the delivery of prophylaxis.

Many of the important questions come well before an audit of adherence to guidelines. What are the risks associated with sexual assault? What are the risks and benefits of HIV PEP?

These are thorny issues, and it is notable that only a minority of the states in the USA have produced guidelines concerning HIV PEP in adolescents. In the UK there are no national guidelines. In 2002 the Medical Society for the Study of Venereal Diseases surveyed opinion and practice in genitourinary medicine clinics across the UK.2 Since 1997, requests and prescriptions for HIV PEP had risen fourfold to 242 and sevenfold to 130 respectively. Most clinicians surveyed would prescribe prophylaxis where a known HIV positive person had assaulted an HIV negative person.

Regarding risk, the authors quote seroconversion rates of 0.1%–0.2% after vaginal and 0.1%–3% after anal intercourse. The rate is probably higher in assault because of the greater incidence of traumatic penetration. However, these are not the risks of the adolescent in front of you. The risk for the adolescent is multiplied by the fractional chance that the assailant has HIV. Thus, in sub-Saharan Africa I would want HIV PEP but in rural England I would feel very differently. None of the New York group knew the HIV status of their assailant—and if they did I would question whether this information should be relied upon. The prevalence of HIV in any given population demonstrates extreme regional, gender, and lifestyle variation. The PHLS currently estimates on overall prevalence in the UK of 1:1000. If prevalence rates reflect attendances for care then the prevalence is about 20 times greater in London than in any other region and much greater still in black Africans.3

Regarding benefit, the authors provide an honest review. There is no direct evidence. The benefit quoted for occupational HIV PEP (a fivefold risk reduction) is based on a sophisticated case-control study. While Cardo and colleagues made every effort to optimise their data, the sample of cases is small and the controls are retrospective.4 Certainly PEP should not be regarded as a proved and effective treatment for occupational exposure, and any extrapolation to the non-occupational setting can only be based on (reasonable) assumptions.

Anyone who has provided health care to this group of patients is well aware of the problems. A typical recommendation is a six week to three month course of triple therapy. Most patients report significant side effects and some are unable to work or attend school for the duration of treatment. There have been two case reports of liver failure requiring transplantation. Compliance is poor.

It is this author’s view from the front line that the complexity of individual risk assessment, the lack of evidence for effectiveness, the severity of side effects, and the multiple factors that determine compliance, make each decision about HIV PEP unique. It is no coincidence that guidelines are few and non-prescriptive. If you have immediate access to a genitourinary clinic or advice then discuss early. If not, then don’t let concern over the very low risk of HIV blind you to the far more prevalent issues of chlamydial infection, psychological trauma, and child protection. Consider a baseline HIV test or at least saving some serum for future reference.

The decision for HIV post-exposure prophylaxis after sexual assault should be considered on an individual basis


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