We conducted a systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact. The search to September 2008 identified 43 publications based on 25 different study populations. Pooled female-to-male (0·0004,95%CI=0·0001-0·0014) and male-to-female (0·0008,CI=0·0006-0·0011) transmission estimates in developed countries reflected a low risk of infection in the absence of antiretrovirals. Developing country female-to-male (0·0038,CI=0·0013-0·0110) and male-to-female (0·0030,CI=0·0014-0·0063) estimates in absence of commercial sex(CS) work were higher. In meta-regression analysis, the infectivity across estimates in absence of CS work was significantly associated with gender, setting, the interaction between setting and gender and HIV prevalence. The pooled receptive anal intercourse estimate was much higher (0·017,CI=0·003-0·089). Estimates for the early and late phase of HIV infection were 9·2(CI=4·5-18·8) and 7·3(CI=4·5-11·9)-fold larger than for the asymptomatic phase, respectively. After adjusting for CS exposure, presence or history of genital ulcers in either couple member increased per-act infectivity 5·3(CI=1·4-19·5)-fold compared to no sexually transmitted infection. Study estimates among non-circumcised men were at least twice those among circumcised men. Developing country estimates were more heterogeneous than developed country estimates, which indicates poorer study quality, greater heterogeneity in risk factors or under-reporting of high-risk behaviour. Efforts are needed to better understand these differences and quantify infectivity in developing countries.

Objective To determine the safety and effectiveness of BufferGel and 0.5% PRO2000 microbicide gels for the prevention of male to female HIV transmission Design Phase II/IIb, randomized, placebo-controlled trial with three double-blinded gel arms and an open label no gel arm. Methods Study participants from Malawi, South Africa, Zambia, Zimbabwe and USA were instructed to apply study gel ≤1 hour before each sex act and safety, sexual behavior, pregnancy, gel adherence, acceptability, and HIV serostatus were assessed during follow-up. Results The 3101 enrolled women were followed for an average of 20.4 months with 93.6% retention and 81.1% self-reported gel adherence. Adverse event rates were similar in all study arms. HIV incidence rates in the 0.5% PRO2000 Gel, BufferGel, Placebo Gel and No Gel arms were 2.70, 4.14, 3.91 and 4.02 per 100 women-years, respectively. HIV incidence in the 0.5% PRO2000 Gel arm was lower than the Placebo Gel arm (Hazard Ratio (HR)=0.7; p=0.10) and the No Gel arm (HR=0.67; p=0.06). HIV incidence rates were similar in the BufferGel and both Placebo Gel (HR=1.10; p=0.63) and No Gel control arms (HR=1.05; p=0.78). HIV incidence was similar in the Placebo Gel and No Gel arms (HR=0.97; p=0.89). Conclusions 0.5% PRO2000 Gel demonstrated a modest 30% reduction in HIV acquisition in women. However, these results were not statistically significant and subsequent findings from the MDP 301 trial have confirmed that 0.5% PRO2000 has little or no protective effect. BufferGel did not alter the risk of HIV infection. Both products were safe.

The high incidence of HIV infection places St Petersburg among the worst IDU-concentrated epidemics in Europe. Interventions targeting psychostimulant and heroin users and their accompanying behaviors such as frequent injections and increased sexual activity are needed immediately.

Heterosexual anal intercourse confers a much greater risk of HIV transmission than vaginal intercourse, yet its contribution to heterosexual HIV epidemics has been under researched. In this article we review the current state of knowledge of heterosexual anal intercourse practice worldwide and identify the information required to assess its role in HIV transmission within heterosexual populations, including input measures required to inform mathematical models. We then discuss the evidence relating anal intercourse and HIV with sexual violence.