Biological correlates of sexual transmission of HIV: practical consequences and potential targets for public health:

Antiretroviral therapy as HIV prevention: status and prospects

As antiretroviral treatment of HIV infection has become increasingly accessible, attention has focused on whether these drugs can used for prevention because of increased tolerability of newer medications, decreased cost, and the limitations of other approaches. We review the status of antiretroviral HIV prevention, including chemoprophylaxis, as well as the effects of treatment of infected individuals on prevention. It is possible that the life-saving agents that have transformed the natural history of AIDS can be a critical component of HIV prevention efforts, but their ultimate role in affecting HIV transmission dynamics remains to be defined.

Brief motivational interventions for HIV/STI risk reduction among individuals receiving alcohol detoxification

This HIV/STI risk reduction clinical trial implemented in short-term alcohol detoxification employed a randomized block design to evaluate three intervention conditions for feasibility, safety, and potential for changing sexual risk attitudes, motivations, and behavior: (a) nonintervention control (standard HIV information dissemination), (b) brief motivational intervention (BMI) for resolution of ambivalence and sex risk reduction planning, and (c) BMI with biological feedback based on testing for sexually transmitted infections (STIs). Findings revealed that BMI can be feasibly implemented during detoxification treatment with individuals with significant substance impairment. BMI, whether coupled with biological feedback or not, enhanced motivation for increasing behaviors that protect from STI. Sexual risk behavior did not change in any of the groups to a statistically significant degree; however, additional analyses suggest negative biological feedback may have resulted in slightly increased level of sexual activity, undoing behavioral effects of increased motivation for sexual risk reduction, perhaps by distorting participants' perception of risk.

Potential impact of early antiretroviral therapy on transmission

PURPOSE OF REVIEW

In this review, we will discuss the potential of early highly active antiretroviral therapy (HAART) to reduce the sexual transmission of HIV on an individual and population level. We will focus on the biological plausibility and behavioural factors associated with HAART use and interventions that might influence such a strategy.

RECENT FINDINGS

Empiric and phylogenetic studies support the view that recent HIV infection is a highly infectious disease stage. Evidence increasingly demonstrates that individuals on fully suppressive HAART are significantly less likely to transmit HIV to sexual partners and some even suggest that such individuals cannot transmit HIV. Changes in risk behaviour are associated with the availability of HAART but behavioural studies offer contradictory observations regarding the direction and magnitude of these changes. This in turn makes the intricate assumptions and therefore outcomes of many complex mathematical modelling studies less secure. Furthermore, there is evidence that it is those individuals with undiagnosed HIV infection who contribute significantly to onward sexual transmission.

SUMMARY

At an individual level, HAART will reduce viral load and, therefore, infectiousness, although whether to zero or not remains controversial. At a population level, if recent infection and undiagnosed infections continue to drive onward transmission, earlier treatment will only alter the pandemic if accompanied by an improvement in diagnosing the undiagnosed and recognizing recent infection.

Protease inhibitor and nonnucleoside reverse transcriptase inhibitor concentrations in the genital tract of HIV-1-infected women

The pharmacokinetics of antiretrovirals (ARVs) in the female genital tract (FGT) are likely to influence vertical and sexual transmission of HIV, the development of viral resistance, and post-exposure prophylaxis regimens. This study is the first to compare ARV concentrations in direct aspirates of cervicovaginal fluid (CVF) and blood plasma (BP). This unique method provides direct assessment of concentrations without the confounding of cervicovaginal lavage dilution. Of 8 ARVs, CVF concentrations ranged from <10% to >100% of BP concentrations. These large differences in CVF penetration suggest that further research into ARV pharmacokinetics and drug efficacy in the FGT is necessary.

HIV/AIDS in Asia

HIV (ie, HIV-1) epidemics in Asia show great diversity, both in severity and timing. But epidemics in Asia are far from over and several countries including China, Indonesia, and Vietnam have growing epidemics. Several factors affect the rate and magnitude of growth of HIV prevalence, but two of the most important are the size of the sex worker population and the frequency with which commercial sex occurs. In view of the present state of knowledge, even countries with low prevalence of infection might still have epidemics affecting a small percentage of the population. Once HIV infection has become established, growing needs for care and treatment are unavoidable and even the so-called prevention-successful countries of Thailand and Cambodia are seeing burgeoning care needs. The manifestations of HIV disease in the region are discussed with the aim of identifying key issues in medical management and care of HIV/AIDS. In particular, issues relevant to developing appropriate highly active antiretroviral treatment programmes in the region are discussed. Although access to antiretroviral therapy is increasing globally, making it work effectively while simultaneously expanding prevention programmes to stem the flow of new infections remains a real challenge in Asia. Genuine political interest and commitment are essential foundations for success, demanding advocacy at all levels to drive policy, mobilise sufficient resources, and take effective action.

Effects of formulation and dosing strategy on amprenavir concentrations in the seminal plasma of human immunodeficiency virus type 1-infected men

We compared seminal plasma pharmacokinetic data for the investigational amprenavir prodrug GW433908 with those for amprenavir and an amprenavir-ritonavir combination regimen. All 3 regimens resulted in detectable blood plasma and seminal plasma concentrations of amprenavir. The majority of these concentrations were greater than the plasma protein-corrected 50% inhibitory concentration for wild-type human immunodeficiency virus type 1.

Can antiretroviral therapy be used to prevent sexual transmission of human immunodeficiency virus type 1?

Approximately 5 million people annually are newly infected with human immunodeficiency virus (HIV). Although education, behavior modification, and promotion of condom use are effective transmission-prevention measures, the severity of the pandemic demands that all possible prevention strategies be explored. Antiretroviral therapy has the potential to decrease sexual transmission of HIV type 1 by reducing levels of HIV RNA and thus decreasing the risk that infected persons will transmit the disease or by its use as preexposure or postexposure prophylaxis. In this article, we explore the rationale for using antiretroviral therapy to prevent sexual transmission of HIV, as well as the limitations of this approach.