Randomized, controlled intervention trial of male circumcision for reduction of HIV infection risk: the ANRS 1265 Trial

When should potentially false research findings be considered acceptable?

Ioannidis estimated that most published research findings are false, but he did not indicate when, if at all, potentially false research results may be considered as acceptable to society. We combined our two previously published models to calculate the probability above which research findings may become acceptable. A new model indicates that the probability above which research results should be accepted depends on the expected payback from the research (the benefits) and the inadvertent consequences (the harms). This probability may dramatically change depending on our willingness to tolerate error in accepting false research findings. Our acceptance of research findings changes as a function of what we call "acceptable regret," i.e., our tolerance of making a wrong decision in accepting the research hypothesis. We illustrate our findings by providing a new framework for early stopping rules in clinical research (i.e., when should we accept early findings from a clinical trial indicating the benefits as true?). Obtaining absolute "truth" in research is impossible, and so society has to decide when less-than-perfect results may become acceptable.

Circumcision for prevention against HIV: marked seasonal variation in demand and potential public sector readiness in Soweto, South Africa

The public sector delivery of male circumcision in the only public sector hospital in Soweto, South Africa was examined to gauge local capacity to deliver this procedure as an intervention for prevention of HIV acquisition. During the period from July 1998 to March 2006, approximately 360 procedures were performed per annum. Striking seasonal variations and the relatively few procedures performed may create challenges for program planning, if male circumcision is increased to a level required to have an impact on the incidence of HIV among this population.

Male Circumcision in Siaya and Bondo Districts, Kenya

BACKGROUND

Evidence for efficacy of male circumcision as an HIV prevention measure is increasing, but there is serious concern that men who are circumcised may subsequently adopt more risky sexual behaviors.

METHODS

Using a prospective cohort study, we compared sexual behaviors of 324 recently circumcised and 324 uncircumcised men at 1, 3, 6, 9, and 12 months after circumcision/study enrollment. The main outcome indicators were incidence of sexual behaviors known to place men at increased risk of acquiring HIV, namely, having sex with partners other than their wife/wives for married men or other than "regular" girlfriends for unmarried men.

RESULTS

During the first month following circumcision, men were 63% and 61% less likely to report having 0 to 0.5 and >0.5 risky sex acts/week, respectively, than men who remained uncircumcised. This difference disappeared during the remainder of follow-up, with no excess of reported risky sex acts among circumcised men. Similar results were observed for risky unprotected sex acts, number of risky sex partners, and condom use.

DISCUSSION

During the first year post-circumcision, men did not engage in more risky sexual behaviors than uncircumcised men, suggesting that any protective effect of male circumcision on HIV acquisition is unlikely to be offset by an adverse behavioral impact.

Could the CARE-SHAKTI intervention for injecting drug users be maintaining the low HIV prevalence in Dhaka, Bangladesh?

AIMS

To explore whether the low HIV prevalence observed in Bangladesh results from prevention activities, this study uses mathematical modelling to estimate the impact of a needle/syringe exchange intervention for injecting drug users (IDUs) in Dhaka, Bangladesh.

DESIGN

Epidemiological, behavioural and intervention monitoring data were used to parameterize a dynamic mathematical model, and fit it to National HIV Sero-surveillance data among IDUs (2000-02). The model was used to estimate the impact of the intervention on HIV transmission among IDUs and their sexual partners.

SETTING

Dhaka, Bangladesh, where the HIV prevalence has remained low despite high-risk sexual and injecting behaviours, and growing HIV epidemics in neighbouring countries.

FINDINGS

The model predicts that the intervention may have reduced the incidence of HIV among IDUs by 90% (95% CI 74-94%), resulting in an IDU HIV prevalence of 10% (95% CI 4-19%) after 8 years of intervention activity instead of 42% (95% CI 30-47%) if the intervention had not occurred.

CONCLUSIONS

The analysis highlights the potential for rapid HIV spread among IDUs in Dhaka, and suggests that the intervention may have substantially reduced IDU HIV transmission. However, there is no room for complacency. Sustained and expanded funding for interventions in Dhaka and other regions of Bangladesh are crucial to maintaining the low HIV prevalence.

The role of sexually transmitted infections in male circumcision effectiveness against HIV--insights from clinical trial simulation

Background

A landmark randomised trial of male circumcision (MC) in Orange Farm, South Africa recently showed a large and significant reduction in risk of HIV infection, reporting MC effectiveness of 61% (95% CI: 34%–77%). Additionally, two further randomised trials of MC in Kisumu, Kenya and Rakai, Uganda were recently stopped early to report 53% and 48% effectiveness, respectively. Since MC may protect against both HIV and certain sexually transmitted infections (STI), which are themselves cofactors of HIV infection, an important question is the extent to which this estimated effectiveness against HIV is mediated by the protective effect of circumcision against STI. The answer lies in the trial data if the appropriate statistical analyses can be identified to estimate the separate efficacies against HIV and STI, which combine to determine overall effectiveness.

Objectives and Methods

Focusing on the MC trial in Kisumu, we used a stochastic prevention trial simulator (1) to determine whether statistical analyses can validly estimate efficacy, (2) to determine whether MC efficacy against STI alone can produce large effectiveness against HIV and (3) to estimate the fraction of all HIV infections prevented that are attributable to efficacy against STI when both efficacies combine.

Results

Valid estimation of separate efficacies against HIV and STI as well as MC effectiveness is feasible with available STI and HIV trial data, under Kisumu trial conditions. Under our parameter assumptions, high overall effectiveness of MC against HIV was observed only with a high MC efficacy against HIV and was not possible on the basis of MC efficacy against STI alone. The fraction of all HIV infections prevented which were attributable to MC efficacy against STI was small, except when efficacy of MC specifically against HIV was very low. In the three MC trials which reported between 48% and 61% effectiveness (combining STI and HIV efficacies), the fraction of HIV infections prevented in circumcised males which were attributable to STI was unlikely to be more than 10% to 20%.

Conclusion

Estimation of efficacy, attributable fraction and effectiveness leads to improved understanding of trial results, gives trial results greater external validity and is essential to determine the broader public health impact of circumcision to men and women.

Interactions between schistosomiasis and infection with HIV-1

In many regions of the world, both schistosomiasis and HIV/AIDS are endemic, resulting in patients harbouring co-infections. Because interaction with host CD4(+) T cells is a characteristic of schistosome as well as HIV-1 infections, bi-directional disease effects may be sufficiently different from sequelae caused by either infectious agent alone to warrant alteration of public health approaches in areas of co-endemnicity. Studies published over the past decade provide useful insights into interactions between schistosomiasis and infection with HIV-1, and overall support the hypothesis that special emphasis on treatment of schistosomiasis in populations with elevated prevalence or risk of HIV-1 infection is justified.

Global control of sexually transmitted infections

Sexually transmitted infections other than HIV are important global health issues. They have, however, been neglected as a public-health priority and control efforts continue to fail. Sexually transmitted infections, by their nature, affect individuals, who are part of partnerships and larger sexual networks, and in turn populations. We propose a framework of individual, partnership, and population levels for examining the effects of sexually transmitted infections and interventions to control them. At the individual level we have a range of effective diagnostic tests, treatments, and vaccines. These options are unavailable or inaccessible in many resource-poor settings, where syndromic management remains the core intervention for individual case management. At the partnership level, partner notification and antenatal syphilis screening have the potential to prevent infection and re-infection. Interventions delivered to whole populations, or groups in whom the risks of infection and onward transmission are very high, have the greatest potential effect. Improvements to the infrastructure of treatment services can reduce the incidence of syphilis and gonorrhoea or urethritis. Strong evidence for the effectiveness of most other interventions on population-level outcomes is, however, scarce. Effective action requires a multifaceted approach including better basic epidemiological and surveillance data, high quality evidence about effectiveness of individual interventions and programmes, better methods to get effective interventions onto the policy agenda, and better advocacy and more commitment to get them implemented properly. We must not allow stigma, prejudice, and moral opposition to obstruct the goals of infectious disease control.

Cost-effectiveness of male circumcision for HIV prevention in a South African setting

BACKGROUND

Consistent with observational studies, a randomized controlled intervention trial of adult male circumcision (MC) conducted in the general population in Orange Farm (OF) (Gauteng Province, South Africa) demonstrated a protective effect against HIV acquisition of 60%. The objective of this study is to present the first cost-effectiveness analysis of the use of MC as an intervention to reduce the spread of HIV in sub-Saharan Africa.

METHODS AND FINDINGS

Cost-effectiveness was modeled for 1,000 MCs done within a general adult male population. Intervention costs included performing MC and treatment of adverse events. HIV prevalence was estimated from published estimates and incidence among susceptible subjects calculated assuming a steady-state epidemic. Effectiveness was defined as the number of HIV infections averted (HIA), which was estimated by dynamically projecting over 20 years the reduction in HIV incidence observed in the OF trial, including secondary transmission to women. Net savings were calculated with adjustment for the averted lifetime duration cost of HIV treatment. Sensitivity analyses examined the effects of input uncertainty and program coverage. All results were discounted to the present at 3% per year. For Gauteng Province, assuming full coverage of the MC intervention, with a 2005 adult male prevalence of 25.6%, 1,000 circumcisions would avert an estimated 308 (80% CI 189-428) infections over 20 years. The cost is 181 dollars (80% CI 117-306 dollars) per HIA, and net savings are 2.4 million dollars (80% CI 1.3 million to 3.6 million dollars). Cost-effectiveness is sensitive to the costs of MC and of averted HIV treatment, the protective effect of MC, and HIV prevalence. With an HIV prevalence of 8.4%, the cost per HIA is 551 dollars (80% CI 344-1,071 dollars) and net savings are 753,000 (80% CI 0.3 million to 1.2 million dollars). Cost-effectiveness improves by less than 10% when MC intervention coverage is 50% of full coverage.

CONCLUSIONS

In settings in sub-Saharan Africa with high or moderate HIV prevalence among the general population, adult MC is likely to be a cost-effective HIV prevention strategy, even when it has a low coverage. MC generates large net savings after adjustment for averted HIV medical costs.

Male circumcision, religion, and infectious diseases: an ecologic analysis of 118 developing countries

Background

Both religious practices and male circumcision (MC) have been associated with HIV and other sexually-transmitted infectious diseases. Most studies have been limited in size and have not adequately controlled for religion, so these relationships remain unclear.

Methods

We evaluated relationships between MC prevalence, Muslim and Christian religion, and 7 infectious diseases using country-specific data among 118 developing countries. We used multivariate linear regression to describe associations between MC and cervical cancer incidence, and between MC and HIV prevalence among countries with primarily sexual HIV transmission.

Results

Fifty-three, 14, and 51 developing countries had a high (>80%), intermediate (20–80%), and low (<20%) MC prevalence, respectively. In univariate analyses, MC was associated with lower HIV prevalence and lower cervical cancer incidence, but not with HSV-2, syphilis, nor, as expected, with Hepatitis C, tuberculosis, or malaria. In multivariate analysis after stratifying the countries by religious groups, each categorical increase of MC prevalence was associated with a 3.65/100,000 women (95% CI 0.54-6.76, p = 0.02) decrease in annual cervical cancer incidence, and a 1.84-fold (95% CI 1.36-2.48, p < 0.001) decrease in the adult HIV prevalence among sub-Saharan African countries. In separate multivariate analyses among non-sub-Saharan African countries controlling for religion, higher MC prevalence was associated with a 8.94-fold (95% CI 4.30-18.60) decrease in the adult HIV prevalence among countries with primarily heterosexual HIV transmission, but not, as expected, among countries with primarily homosexual or injection drug use HIV transmission (p = 0.35).

Conclusion

Male circumcision was significantly associated with lower cervical cancer incidence and lower HIV prevalence in sub-Saharan Africa, independent of Muslim and Christian religion. As predicted, male circumcision was also strongly associated with lower HIV prevalence among countries with primarily heterosexual HIV transmission, but not among countries with primarily homosexual or injection drug use HIV transmission. These findings strengthen the reported biological link between MC and some sexually transmitted infectious diseases, including HIV and cervical cancer.

Understanding the scourge of HIV/AIDS in sub-Saharan Africa

Sub-Saharan Africa is the part of the world that has been hit hardest by the HIV epidemic. To fight the spread of HIV in the continent, it is necessary to know and effectively address the factors that drive the spread of HIV. The purpose of this article is to review the factors associated with the spread of the HIV epidemic in sub-Saharan Africa and to propose 6 essential activities, which we refer to by the acronym "ESCAPER," to help curb the spread of HIV/AIDS in Africa.

Criteria for drugs used in pre-exposure prophylaxis trials against HIV infection

The authors formulate criteria for an optimal pre-exposure prophylaxis drug candidate, and evaluate existing antiviral drug classes for their suitability.

Circumcision status and risk of sexually transmitted infection in young adult males: an analysis of a longitudinal birth cohort

OBJECTIVES

Previous research suggests that male circumcision may be a protective factor against the acquisition of sexually transmitted infections; however, studies examining this question have produced mixed results. The aim of this study was to examine the association between circumcision status and sexually transmitted infection risk using a longitudinal birth cohort study.

METHODS

Data were gathered as part of the Christchurch Health and Development Study, a 25-year longitudinal study of a birth cohort of New Zealand children. Information was obtained on: (1) the circumcision status of males in the cohort before 15 years old, (2) measures of self-reported sexually transmitted infection from ages 18 to 25 years, and (3) childhood, family, and related covariate factors.

RESULTS

Being uncircumcised had a statistically significant bivariate association with self-reported sexually transmitted infection. Adjustment for potentially confounding factors, including number of sexual partners and unprotected sex, as well as background and family factors related to circumcision, did not reduce the association between circumcision status and reports of sexually transmitted infection. Estimates of the population-attributable risk suggested that universal neonatal circumcision would have reduced rates of sexually transmitted infection in this cohort by 48.2%.

CONCLUSIONS

These findings suggest that uncircumcised males are at greater risk of acquiring sexually transmitted infection than circumcised males. Male circumcision may reduce the risk of sexually transmitted infection acquisition and transmission by up to one half, suggesting substantial benefits accruing from routine neonatal circumcision.

Strategies for global HIV prevention

Despite significant advances in the development of therapeutic strategies for HIV over the past 25 years, the AIDS pandemic continues to grow worldwide. Access to life-saving medicines is not universal and there is a critical need for better prevention strategies. This review will highlight current research in the area of HIV prevention strategies, including preventive HIV vaccines, effective microbicides, treatment of sexually transmitted infections and the impact on HIV transmission, in addition to the role of male circumcision and pre-exposure prophylaxis with antiretroviral medications in HIV prevention.

Independent association of hygiene, socioeconomic status, and circumcision with reduced risk of HIV infection among Kenyan men

Among Kenyan men recruited as sex partners of women with genital symptoms, 22 of 150 were HIV seropositive. Because male HIV infection and male hygiene were unexpectedly found to be associated with each other, we examined the relationship of 5 hygiene variables with HIV infection in the men in a principal components analysis, controlling for socioeconomic status and other potential confounders. By multivariate analyses, HIV infection in men was not only independently associated with previous illness (odds ratio [OR], 5.1; 95% confidence interval [CI], 1.4-19.1) and inversely associated with being circumcised (OR, 0.12; 95% CI, 0.02-0.91), but also independently associated with a combined measure of hygiene (OR, 0.41; 95% CI, 0.19-0.90).

Country-wide distribution of the nitrile female condom (FC2) in Brazil and South Africa: a cost-effectiveness analysis

OBJECTIVE

To evaluate the cost-effectiveness and potential impact of expanded female condom distribution.

DESIGN

Cost-effectiveness analysis assessing HIV infections averted annually and incremental cost per HIV infection averted for country-wide distribution of the nitrile female condom (FC2) among sexually active individuals, 15-49 years, with access to publicly distributed condoms in Brazil and South Africa.

RESULTS

In Brazil, expansion of FC2 distribution to 10% of current male condom use would avert an estimated 604 (5-95th percentiles, 412-831) HIV infections at 20,683 US dollars (5-95th percentiles, 13,497-29,521) per infection averted. In South Africa, 9577 (5-95th percentiles, 6539-13,270) infections could be averted, at 985 US dollars (5-95th percentiles, 633-1412) per infection averted. The estimated cost of treating one HIV-infected individual is 21,970 US dollars (5-95th percentiles, 18,369-25,719) in Brazil and 1503 US dollars (5-95th percentiles, 1245-1769) in South Africa, indicating potential cost savings. The incremental cost of expanded distribution would be reduced to 8930 US dollars (5-95th percentiles, 5864-13,163) per infection averted in Brazil and 374 US dollars (5-95th percentiles, 237-553) in South Africa by acquiring FC2s through a global purchasing mechanism and increasing distribution threefold. Sensitivity analyses show model estimates to be most sensitive to the estimated prevalence of sexually transmitted infections, total sexual activity, and fraction of FC2s properly used.

CONCLUSIONS

Expanded distribution of FC2 in Brazil and South Africa could avert substantial numbers of HIV infections at little or no net cost to donor or government agencies. FC2 may be a useful and cost-effective supplement to the male condom for preventing HIV.

Factors associated with HIV sero-positivity in young, rural South African men

OBJECTIVE

To describe factors associated with HIV infection in men aged 15-26 years.

SETTING

Rural Eastern Cape Province, South Africa.

SAMPLE

A total of 1277 sexually experienced Xhosa male volunteers from 70 villages participating in a cluster randomized controlled trial of an HIV behavioural intervention. Xhosas circumcise during manhood initiation rituals.

DESIGN

Cross-sectional, analysis of the study's baseline interviews.

MAIN MEASURE

HIV sero-status, sexual practices measured with an interviewer-administered questionnaire.

RESULTS

About 2% of the men were HIV positive. A logistic regression model showed HIV positivity to be associated with age (OR 1.55; 95%CI 1.22-1.95), having made a woman pregnant (OR 2.93; 95% CI 1.28-6.68), having been circumcised (OR 0.40; 95% CI 0.16-0.98), and having had sex with a man (OR 3.61; 95% CI 1.0-13.0).

CONCLUSIONS

Our findings provide further evidence to suggest that circumcision is protective. There was much heterosexual risk taking among men but only pregnancy (with its association with sexual frequency) predicted HIV sero-positivity. Although relatively rare, same-sex sexual experiences were a risk factor. Male-male sexual contact is rarely assessed in HIV research in Africa and almost never addressed in general HIV prevention programming. Our findings suggest that it should be given more attention.

What is the achievable effectiveness of the India AIDS Initiative intervention among female sex workers under target coverage? Model projections from southern India

BACKGROUND

The India AIDS Initiative (Avahan) prevention programme funded by the Bill and Melinda Gates Foundation aims to reduce HIV prevalence in high risk groups such as female and male sex workers and their clients, to limit HIV transmission in the general population.

OBJECTIVES

To assess the potential effectiveness of the Avahan intervention at the level of coverage targeted, in different epidemiological settings in India.

METHODS

A deterministic compartmental model of the transmission dynamics of HIV and two sexually transmitted infections, and sensitivity analysis techniques, were used, in combination with available behavioural and epidemiological data from Mysore and Bagalkot districts in the Indian state of Karnataka, to evaluate the syndromic sexually transmitted infection (STI) management (STI treatment), periodic presumptive treatment of STI (PPT), and condom components of the Avahan intervention targeted to female sex workers (FSW).

RESULTS

If all components of the intervention reach target coverage (that is, PPT, STI treatment and condom use), the intervention is expected to prevent 22-35% of all new HIV infections in FSW and in the total population over 5 years in a low transmission setting like Mysore, and to be half as effective in high transmission settings such as Bagalkot. The results were sensitive to small variations in intervention coverage. The condom component alone is expected to prevent around 20% of all new HIV infections over 5 years in Mysore and around 6% for the STI component alone; compared with 7%-14% for the PPT component alone. Multivariate sensitivity analyses suggested that interventions may be more effective in settings with low FSW HIV prevalence and small FSW populations, whereas HIV prevalence was most influenced by sexual behaviour and condom use parameters for FSW.

CONCLUSION

The Avahan intervention is expected to be effective. However, to be able to demonstrate effectiveness empirically in the different settings, it is important to achieve target coverage or higher, which in the case of PPT could take a number of years to achieve. These preliminary model predictions need to be validated with more detailed mathematical models, as better data on sexual behaviour, condom use, STI and HIV trends over time, and intervention coverage data accumulate over the course of the programme.

Parachute approach to evidence based medicine

Waiting for the results of randomised trials of public health interventions can cost hundreds of lives, especially in poor countries with great need and potential to benefit. If the science is good, we should act before the trials are done

Prevention for those who have freedom of choice--or among the choice-disabled: confronting equity in the AIDS epidemic

With the exception of post-exposure prophylaxis for reported rape, no preventive strategy addresses the choice disabled – those who might like to benefit from AIDS prevention but who are unable to do so because they do not have the power to make and to act on prevention decisions. In southern African countries, where one in every three has been forced to have sex by the age of 18 years, a very large proportion of the population is choice disabled. This group is at higher risk of HIV infection and unable to respond to AIDS prevention programmes; they represent a reservoir of infection. Reduction of sexual violence would probably decrease HIV transmission directly, but also indirectly as more people can respond to existing AIDS prevention programmes.

Association Between HIV and Subpreputial Penile Wetness in Uncircumcised Men in South Africa

OBJECTIVES

To describe the prevalence and characteristics of subpreputial penile wetness and to investigate the association between current levels of penile wetness and HIV infection.

METHODS

Male attenders at a sexually transmitted infections clinic in Durban, South Africa were enrolled and treated for their presenting sexually transmitted infection complaint. They were asked to return after 14 days when a structured questionnaire was administered, and the degree of wetness of the glans penis and coronal sulcus was assessed clinically.

RESULTS

Six hundred and fifty men were enrolled, and 488 (75%) returned. Three hundred eighty-six uncircumcised men were included for statistical analysis of whom 215 (56%) were HIV positive. One hundred ninety-six (50.8%) had no penile wetness, and 190 (49.2%) had penile wetness. In the adjusted analysis, penile wetness was associated with younger age, low level of attained education, low income, higher lifetime numbers of sexual partners, and not washing after sex. The prevalence of HIV was greater in those with penile wetness 126 of 190 (66.3%) compared with 90 of 196 (45.9%) with no penile wetness, crude prevalence odds ratio 2.32 (95% confidence interval [CI], 1.54-3.50, P=or<0.001), crude prevalence relative risk 1.44 (95% CI, 1.23-1.63, P=or<0.001), and adjusted for predictors of HIV, confounders and herpes type 2 antibodies, odds ratio 2.38 (95% CI, 1.42-3.97, P=or<0.001), and relative risk 1.46 (95% CI, 1.19-1.68, P=or<0.001).

CONCLUSIONS

This is the first study to show an association between subpreputial penile wetness and HIV. Consideration should be given to providing advice about improving penile hygiene in uncircumcised men in areas where HIV is a significant problem. Good penile hygiene should also be promoted at the community level to become a desirable social norm.

HIV interactions with dendritic cells: has our focus been too narrow?

Although few in number, dendritic cells (DCs) are heterogeneous, ubiquitous, and are crucial for protection against pathogens. In this review, the different DC subpopulations have been described and aspects of DC biology are discussed. DCs are important, not only in the pathogenesis of HIV, but also in the generation of anti-HIV immune responses. This review describes the roles that DC are thought to play in HIV pathogenesis, including uptake and transport of virus. We have also discussed the effects that the virus exerts on DCs such as infection and dysfunction. Then we proceed to focus on DC subsets in different organs and show how widespread the effects of HIV are on DC populations. It is clear that the small number of studies on tissue-derived DCs limits current research into the pathogenesis of HIV.

HIV/AIDS epidemiology, pathogenesis, prevention, and treatment

The HIV-1 pandemic is a complex mix of diverse epidemics within and between countries and regions of the world, and is undoubtedly the defining public-health crisis of our time. Research has deepened our understanding of how the virus replicates, manipulates, and hides in an infected person. Although our understanding of pathogenesis and transmission dynamics has become more nuanced and prevention options have expanded, a cure or protective vaccine remains elusive. Antiretroviral treatment has transformed AIDS from an inevitably fatal condition to a chronic, manageable disease in some settings. This transformation has yet to be realised in those parts of the world that continue to bear a disproportionate burden of new HIV-1 infections and are most affected by increasing morbidity and mortality. This Seminar provides an update on epidemiology, pathogenesis, treatment, and prevention interventions pertinent to HIV-1.

The importance of context: model projections on how microbicide impact could be affected by the underlying epidemiologic and behavioral situation in 2 African settings

OBJECTIVE

The objective of this study was to explore how a microbicide's HIV impact is affected by behavioral and epidemiologic factors in 2 African settings: Cotonou, Benin, and Hillbrow, South Africa.

METHODS

A mathematical model, fit to epidemiologic data from each setting, was used to estimate the HIV impact of introducing a microbicide with different HIV/sexually transmitted infection (STI) efficacies. Simulations were compared to explore how impact is affected by context.

RESULTS

Widespread microbicide use results in a greater relative reduction in HIV incidence in Cotonou, where HIV/STIs are less prevalent. Most infections averted are from commercial sex in Cotonou but noncommercial sex in Hillbrow. The microbicide's STI efficacy is important in determining its HIV impact in both settings, but especially in Cotonou where the microbicide's HIV impact was mainly the result of its STI efficacy.

CONCLUSIONS

It is important to develop and evaluate microbicides that are efficacious against STIs. However, even with the same patterns of use, a microbicide's impact and the importance of its STI efficacy will vary considerably between settings.

Potential HIV-1 target cells in the human penis

OBJECTIVES

To study the distribution of HIV-1 receptors and degree of keratinization in the human penis.

DESIGN

Formalin-fixed penises were obtained from nine uncircumcised cadavers. Foreskins were obtained from 21 healthy adult men undergoing elective circumcision for social reasons. Uncircumcised penises were obtained within 24 h of death from eight men. All tissues were stained for keratin and HIV-1 receptors.

METHODS

Penises from nine formalin fixed cadavers aged 64-80 years were obtained from the Department of Anatomy, University of Melbourne. Foreskins were obtained from 21 men aged 18-64 years following circumcision performed at either the Freemason's or Mercy Private Hospitals, Melbourne, Australia. Fresh penile necropsy specimens from eight uncircumcised men aged 23-63 years were obtained from the Victorian Institute of Forensic Medicine, Melbourne. The degree of keratinization was scored, and the distribution of HIV-1 susceptible cells was mapped in the glans penis, penile urethra, urethral meatus, frenulum and foreskin.

RESULTS

Cells with HIV-1 receptors were present in all penile epithelia, but Langerhans' cells were most superficial in the inner foreskin and frenulum. The inner foreskin had a significantly thinner keratin layer (1.8 +/- 0.1 units), than the outer foreskin (3.3 +/- 0.1), or glans penis (3.3 +/- 0.2), P < 0.05.

CONCLUSIONS

Superficial Langerhans' cells on the inner aspect of the foreskin and frenulum are poorly protected by keratin and thus could play an important role in primary male infection. These findings provide a possible anatomical explanation for the epidemiologically observed protective effect of male circumcision.

Preparing developing countries for efficacy trials

PURPOSE OF REVIEW

For the first time, Africa is poised to test the efficacy of two candidate vaccines. This raises many scientific, logistic, regulatory and ethical challenges for the continent. This review outlines recent developments relating to the epidemiologic, scientific, site development, and standard of care issues relevant to the conduct of these trials in developing countries.

RECENT FINDINGS

The AIDS epidemic in Africa has reached crisis proportions. Despite more than 20 years having passed since the discovery of HIV, there are no effective biomedical interventions. The testing of two adenovirus type 5-vectored HIV vaccine candidates for efficacy is crucial. These vaccines, which seek to elicit cytotoxic T lymphocyte responses, may not prevent infection, but may ameliorate infection and potentially prevent secondary HIV transmission. Efficacy of these vaccines may be impacted by the presence of pre-existing immunity to the vectors and the genetic diversity of HIV. Trials will be conducted in areas of the world with high HIV incidence, and special efforts should be made to enroll young women and adolescents. The development of clinical trial site capacity, technology transfer of immunogenicity assays to in-country laboratories, and expediting high-quality regulatory and ethical review and executing efficacy trials of the highest standard should be seen as paramount by donors, vaccine developers, clinical trial networks and developing world governments.

SUMMARY

HIV vaccine efficacy trials will soon be conducted in Africa.

Declining Prevalence of HIV-Infected Individuals at Risk of Transmitting Drug-Resistant HIV in Denmark during 1997–2004

Background

Transmission of drug-resistant HIV is a potential threat to the substantial clinical benefit of highly active antiretroviral therapy (HAART). To explore the background for the low rates of drug resistance transmission (2–5%) in our population, we estimated acquisition of HIV drug resistance and examined temporal trends in the prevalence of patients at risk of transmitting drug-resistant HIV.

Methods

The study population included all 4,025 patients from The Danish HIV Cohort Study seen during the period 1995–2004. Virological failure to a given drug class was defined as a viral load (VL) >1,000 copies/ml for 120 days while on a HAART regimen including that drug class. In addition, receiving nucleoside reverse transcriptase inhibitors (NRTIs) for 180 days before HAART counted as NRTI failure irrespective of VL. Having experienced failure was considered a proxy for harbouring drug-resistant virus in subsequent observation time. Patients with a current VL >1,000 copies/ml were considered at risk of transmitting HIV.

Results

We found a decrease from 1997 to 2004 in the prevalence of potential transmitters of drug-resistant HIV. The number of these patients with previous NRTI failure decreased from 429 (24% of all patients) in 1998 to 213 (8.0% of all patients) in 2004. Previous protease inhibitor (PI) failure peaked at 279 (14%) in 1999, declining to 142 (5.3%) in 2004. Previous NNRTI failure peaked at 121 patients (4.7%) in 2002, and occurred in 113 patients (4.2%) in 2004. Of all 686 potential transmitters in 2004, 31% had previously experienced NRTI failure, 21% PI failure, and 16% non-NRTI failure.

Conclusion

In the population of HIV-infected individuals in Denmark with complete follow-up, the number at risk of transmitting drug-resistant virus declined over time.

Acceptability of male circumcision for prevention of HIV infection in Malawi

Numerous epidemiological and biological studies report male circumcision (MC) to have a significant protective effect against HIV-1 acquisition. This study assesses the acceptability of MC in four districts in Malawi, a country with high HIV-1 prevalence and low prevalence of MC. Thirty-two focus group discussions were conducted with 159 men and 159 women ages 16-80 years. Acceptability was lower in the north where the practice was little known, higher in younger participants and higher in central and southern districts where MC is practiced by a minority Muslim group (Yao). Barriers to circumcision included fear of infection and bleeding, cost, and pain. Facilitators included hygiene, reduced risk of STI, religion, medical conditions, and enhanced sexual pleasure. If MC services are introduced in Malawi, acceptance is likely to vary by region, but many parents and young men would use the services if they were safe, affordable and confidential.

The potential impact of male circumcision on HIV in Sub-Saharan Africa

BACKGROUND

A randomized controlled trial (RCT) has shown that male circumcision (MC) reduces sexual transmission of HIV from women to men by 60% (32%-76%; 95% CI) offering an intervention of proven efficacy for reducing the sexual spread of HIV. We explore the implications of this finding for the promotion of MC as a public health intervention to control HIV in sub-Saharan Africa.

METHODS AND FINDINGS

Using dynamical simulation models we consider the impact of MC on the relative prevalence of HIV in men and women and in circumcised and uncircumcised men. Using country level data on HIV prevalence and MC, we estimate the impact of increasing MC coverage on HIV incidence, HIV prevalence, and HIV-related deaths over the next ten, twenty, and thirty years in sub-Saharan Africa. Assuming that full coverage of MC is achieved over the next ten years, we consider three scenarios in which the reduction in transmission is given by the best estimate and the upper and lower 95% confidence limits of the reduction in transmission observed in the RCT. MC could avert 2.0 (1.1-3.8) million new HIV infections and 0.3 (0.1-0.5) million deaths over the next ten years in sub-Saharan Africa. In the ten years after that, it could avert a further 3.7 (1.9-7.5) million new HIV infections and 2.7 (1.5-5.3) million deaths, with about one quarter of all the incident cases prevented and the deaths averted occurring in South Africa. We show that a) MC will increase the proportion of infected people who are women from about 52% to 58%; b) where there is homogenous mixing but not all men are circumcised, the prevalence of infection in circumcised men is likely to be about 80% of that in uncircumcised men; c) MC is equivalent to an intervention, such as a vaccine or increased condom use, that reduces transmission in both directions by 37%.

CONCLUSIONS

This analysis is based on the result of just one RCT, but if the results of that trial are confirmed we suggest that MC could substantially reduce the burden of HIV in Africa, especially in southern Africa where the prevalence of MC is low and the prevalence of HIV is high. While the protective benefit to HIV-negative men will be immediate, the full impact of MC on HIV-related illness and death will only be apparent in ten to twenty years.

Microbicides and other topical strategies to prevent vaginal transmission of HIV

The HIV epidemic is, by many criteria, the worst outbreak of infectious disease in history. The rate of new infections is now approximately 5 million per year, mainly in the developing world, and is increasing. Women are now substantially more at risk of infection with HIV than men. With no cure or effective vaccine in sight, a huge effort is required to develop topical agents (often called microbicides) that, applied to the vaginal mucosa, would prevent infection of these high-risk individuals. We discuss the targets for topical agents that have been identified by studies of the biology of HIV infection and provide an overview of the progress towards the development of a usable agent.

Greater risk for HIV infection of black men who have sex with men: a critical literature review

HIV rates are disproportionately higher for Black men who have sex with men (MSM) than for other MSM. We reviewed the literature to examine 12 hypotheses that might explain this disparity. We found that high rates of HIV infection for Black MSM were partly attributable to a high prevalence of sexually transmitted diseases that facilitate HIV transmission and to undetected or late diagnosis of HIV infection; they were not attributable to a higher frequency of risky sexual behavior, nongay identity, or sexual nondisclosure, or to reported use of alcohol or illicit substances. Evidence was insufficient to evaluate the remaining hypotheses.Future studies must address these hypotheses to provide additional explanations for the greater prevalence of HIV infection among Black MSM.

New ways of preventing HIV infection: thinking simply, simply thinking

HIV infection is the greatest health crisis in human history. It continues to spread unchecked among the poor in the developing world because we have failed to design simple preventative methods that are available and affordable to those living on under Dollars 2 a day. Five new methods are discussed. (i) A natural microbicide. Intravaginal lime or lemon juice has been used for centuries as a traditional contraceptive. The juice can also kill HIV in the laboratory, but clinical trials are needed to see if vaginal application is acceptable, safe and effective. (ii) Intravaginal oestrogen. Monkeys can be protected from Simian immunodeficiency virus (SIV) infection by keratinizing the vagina with topical oestrogen. If women take the oral contraceptive pill vaginally it retains its contraceptive efficacy, and the oestrogen it contains should thicken the vagina and protect against HIV infection. Clinical trials are needed. (iii) Male circumcision. Removal of the inner foreskin removes the main site of HIV entry into the penis, resulting in a sevenfold reduction in susceptibility to infection. The practice needs to be promoted. (iv) Post-coital penile hygiene. Wiping the penis immediately after intercourse with lime or lemon juice or vinegar should kill the virus before it has had a chance to infect. A clinical trial of efficacy is needed. (v) PhotoVoice. Asking schoolchildren in developing countries to photograph their impressions of HIV/AIDS is a powerful way of getting them to discuss the subject openly, and develop their own preventative strategies.

Selective transmission of CCR5-utilizing HIV-1: the 'gatekeeper' problem resolved?

Understanding the mechanisms of HIV-1 transmission is crucial for the development of effective preventive microbicides and vaccine strategies, and remains one of the main goals of HIV research. Over the past decade, many studies have focused on trying to identify the 'gatekeeping' mechanism that restricts the transmission of CXCR4-utilizing HIV-1 more efficiently than CCR5-utilizing HIV-1. However, to date, no study has explained the almost perfect negative selection of the former in vivo. Here, we propose that there is no single gatekeeper and that, instead, the selective transmission of R5 HIV-1 depends on the superimposition of multiple imperfect gatekeepers.

Risk compensation: the Achilles' heel of innovations in HIV prevention?

The benefits of new methods of prevention of HIV could be jeopardised if they are not accompanied by efforts to change risky behaviour

The Global Impact of Scaling Up HIV/AIDS Prevention Programs in Low- and Middle-Income Countries

A strong, global commitment to expanded prevention programs targeted at sexual transmission and transmission among injecting drug users, started now, could avert 28 million new HIV infections between 2005 and 2015. This figure is more than half of the new infections that might otherwise occur during that period in 125 low- and middle-income countries. Although preventing these new infections would require investing about U.S.$122 billion over this period, it would reduce future needs for treatment and care. Our analysis suggests that it will cost about U.S.$3900 to prevent each new infection, but that this will produce a savings of U.S.$4700 in forgone treatment and care costs. Thus, greater spending on prevention now would not only prevent more than half the new infections that would occur from 2005 to 2015 but would actually produce a net financial saving as future costs for treatment and care are averted.

How do viral and host factors modulate the sexual transmission of HIV? Can transmission be blocked?

A better understanding of sexual transmission, say the authors, will enable more rational design of vaccines and microbicides and potential combinations of the two.

Demographic predictors of circumcision status in a community-based sample of homosexual men in Sydney, Australia

Male circumcision may reduce the risk of HIV acquisition in heterosexual men. In observational studies, confounding by demographic factors could produce spurious associations between circumcision and HIV risk. To assess this possibility, cross-sectional data on self-reported circumcision status and demographic factors were collected at baseline as part of the Health in Men study. Two-thirds of 1426 subjects were circumcised, mostly in the neonatal period. In multivariate analyses, age, ethnicity and country of birth were independently associated with circumcision status. Confounding by these demographic factors must be considered in future epidemiological studies addressing circumcision and HIV acquisition.