Per-contact probability of HIV transmission in homosexual men in Sydney in the era of HAART

Postexposure prophylaxis for HIV following sexual exposure

PURPOSE OF REVIEW

Postexposure prophylaxis (PEP) has become an important part of combined approaches to the prevention of onward HIV transmission. As PEP becomes more widely available after sexual as well as occupational exposure, there are ongoing debates about cost-effectiveness and utility. Different regions have adopted different PEP strategies and the availability of new antiretroviral drugs and classes means that options for PEP regimens are increasing. This review is timely and of importance as it summarizes the evidence supporting current PEP usage and discusses potential future strategies for PEP prescribing.

RECENT FINDINGS

This review covers the biology and risk of HIV transmission and evidence supporting the use of PEP. It gives a summary of current guidelines including which agents to use, the potential for drug-drug interactions, possible alternative and potential novel PEP regimens, cost-effectiveness and research on effects of PEP on sexual behaviour.

SUMMARY

While reinforcing current practice around PEP prescribing, this review discusses possible future developments including the use of new antiretroviral drugs, new classes of antiretroviral drugs or novel strategies for PEP which are likely to be areas of research in the near future.

An overview of the relative risks of different sexual behaviours on HIV transmission

PURPOSE OF REVIEW

Sexual intercourse represents the majority of HIV transmission and is preventable. Overall, the risk of HIV transmission following a single sexual exposure is low especially in comparison with other sexually transmitted infections (STIs), with estimates of the average probability of male-to-female HIV transmission only 0.0005-0.0026 per coital act. The risk of acquiring HIV from a single contact varies enormously and is dependant upon the infectiousness of the HIV-positive individual and the susceptibility to HIV of their sexual partner.

RECENT FINDINGS

Of concern, unprotected sex among men who have sex with men (MSM) has increased in recent years and HIV incidence in both MSM and heterosexuals remains a considerable public health concern. Sexual practices and health optimism about HIV have changed, which have significantly impacted HIV risk behaviour.

SUMMARY

In this review article we summarize the current evidence regarding the observed relative risks of HIV transmission for each different types of sex act, relationship type and the strategies that have been tested to interrupt transmission.