Female‐to‐Male Infectivity of HIV‐1 among Circumcised and Uncircumcised Kenyan Men

The Impact of Genital Ulcers on HIV Transmission Has Been Underestimated—A Critical Review

In the early 1990s, several observational studies determined that genital ulcer disease (GUD), in either the index or the exposed person, facilitates HIV transmission. Several meta-analyses have since presented associated risk ratios (RR) over the baseline per-act transmission probability (PATP) usually in the range of 2–5. Here we review all relevant observational studies and meta-analyses, and show that the estimation of RRs was, in most cases, biased by assuming the presence of GUD at any time during long follow-up periods, while active genital ulcers were present in a small proportion of the time. Only two studies measured the GUD co-factor effect in PATPs focusing on acts in which ulcers were present, and both found much higher RRs (in the range 11–112). We demonstrate that these high RRs can be reconciled with the studies on which currently accepted low RRs were based, if the calculations are restricted to the actual GUD episodes. Our results indicate that the effect of genital ulcers on the PATP of HIV might be much greater than currently accepted. We conclude that the medical community should work on the assumption that HIV risk is very high during active genital ulcers.

Clinical patterns of sexually transmitted diseases in human immunodeficiency virus-infected individuals in a tertiary care center in South India

Background:

Human immunodeficiency virus (HIV) and other sexually transmitted diseases (STDs) synergize to aggravate the associated morbidity of each other in the human body.

Aims:

The aim was to study the pattern of presentations of STDs in patients with HIV.

Materials and Methods:

This study was conducted by selecting 100 consecutive cases of HIV infection with symptoms suggestive of co-existing STD attending the outpatient department in a tertiary care center in south India.

Results:

Most of the patients belonged to the age group of 26–30 years, with a slight male preponderance. Genital ulcer was the predominant presenting complaint (60%), followed by dysuria (32%) and genital growth (29%). Genital ulcer was the most common lesion (56%), followed by other genital lesions (37%) and extragenital lesions (18%). Among the investigations, Tzanck smear was most commonly seen positive (62.3% of 61 patients), followed by positive potassium hydroxide mount and Venereal Disease Research Laboratory. About 35.5% of the male patients and 60.53% of the female patients had multiple diagnoses. In males, herpes genitalis (29.76%) was the most common STD, followed by condyloma accuminata (23.08%). In females, candidal vulvovaginitis (28.12%) was the most common STD, followed by herpes genitalis (23.43%).

Conclusion:

Our study found genital ulcer as the most common symptom and sign of STD in HIV-infected patients. Herpes genitalis was the most common STD among males and candidal vulvovaginitis was the most common STD among females.

An economic evaluation of an intervention to increase demand for medical male circumcision among men aged 25-49 years in South Africa

BACKGROUND

Studies estimate that circumcising men between the ages of 20-30 years who have exhibited previous risky sexual behaviour could reduce overall HIV prevalence. Demand creation strategies for medical male circumcision (MMC) targeting men in this age group may significantly impact these prevalence rates.

OBJECTIVES

The objective of this study is to evaluate the cost-effectiveness and cost-benefit of an implementation science, pre-post study designed to increase the uptake of male circumcision for ages 25-49 at a fixed MMC clinic located in Gauteng Province, South Africa.

METHODS

A health care provider perspective was utilised to collect all costs. Costs were compared between the standard care scenario of routine outreach strategies and a full intervention strategy. Cost-effectiveness was measured as cost per mature man enrolled and cost per mature man circumcised. A cost-benefit analysis was employed by using the Bernoulli model to estimate the cases of HIV averted due to medical male circumcision (MMC), and subsequently translated to averted medical costs.

RESULTS

In the 2015 intervention, the cost of the intervention was $9445 for 722 men. The total HIV treatment costs averted due to the intervention were $542,491 from a public care model and $378,073 from a private care model. The benefit-cost ratio was 57.44 for the public care model and 40.03 for the private care model. The net savings of the intervention were $533,046 or $368,628 - depending on treatment in a public or private setting.

CONCLUSIONS

The intervention was cost-effective compared to similar MMC demand interventions and led to statistically significant cost savings per individual enrolled.

HIV incidence among people who inject drugs in the Middle East and North Africa: mathematical modelling analysis

INTRODUCTION

Emerging HIV epidemics have been documented among people who inject drugs (PWID) in the Middle East and North Africa (MENA). This study estimates the HIV incidence among PWID due to sharing needles/syringes in MENA. It also delineates injecting drug use role as a driver of the epidemic in the population, and estimates impact of interventions.

METHODS

A mathematical model of HIV transmission among PWID was applied in seven MENA countries with sufficient and recent epidemiological data and HIV prevalence ≥1% among PWID. Estimations of incident and/or prevalent infections among PWID, ex-PWID and sexual partners of infected current and ex-PWID were conducted.

RESULTS

The estimated HIV incidence rate for 2017 among PWID ranged between 0.7% per person-year (ppy) in Tunisia and 7.8% ppy in Pakistan, with Libya being an outlier (24.8% ppy). The estimated number of annual new infections was lowest in Tunisia (n = 79) and Morocco (n = 99), and highest in Iran and Pakistan (approximately n = 6700 each). In addition, 20 to 2208 and 5 to 837 new annual infections were estimated across the different countries among sexual partners of PWID and ex-PWID respectively. Since epidemic emergence, the number of total ever acquired incident infections across countries was 706 to 90,015 among PWID, 99 to 18,244 among sexual partners of PWID, and 16 to 4360 among sexual partners of ex-PWID. The estimated number of prevalent infections across countries was 341 to 23,279 among PWID, 119 to 16,540 among ex-PWID, 67 to 10,752 among sexual partners of PWID, and 12 to 2863 among sexual partners of ex-PWID. Increasing antiretroviral therapy (ART) coverage to the global target of 81% - factoring in ART adherence and current coverage - would avert about half of new infections among PWID and their sexual partners. Combining ART with harm reduction could avert over 90% and 70% of new infections among PWID and their sexual partners respectively.

CONCLUSIONS

There is considerable HIV incidence among PWID in MENA. Of all new infections ultimately due to injecting drug use, about 75% are among PWID and the rest among sexual partners. Of all prevalent infections ultimately attributed to injecting drug use as epidemic driver, about half are among PWID, 30% among ex-PWID and 20% among sexual partners of PWID and ex-PWID. These findings call for scale-up of services for PWID, including harm reduction as well as testing and treatment services.

Estimating the impact of antiretroviral treatment on adult mortality trends in South Africa: A mathematical modelling study

BACKGROUND

Substantial reductions in adult mortality have been observed in South Africa since the mid-2000s, but there has been no formal evaluation of how much of this decline is attributable to the scale-up of antiretroviral treatment (ART), as previous models have not been calibrated to vital registration data. We developed a deterministic mathematical model to simulate the mortality trends that would have been expected in the absence of ART, and with earlier introduction of ART.

METHODS AND FINDINGS

Model estimates of mortality rates in ART patients were obtained from the International Epidemiology Databases to Evaluate AIDS-Southern Africa (IeDEA-SA) collaboration. The model was calibrated to HIV prevalence data (1997-2013) and mortality data from the South African vital registration system (1997-2014), using a Bayesian approach. In the 1985-2014 period, 2.70 million adult HIV-related deaths occurred in South Africa. Adult HIV deaths peaked at 231,000 per annum in 2006 and declined to 95,000 in 2014, a reduction of 74.7% (95% CI: 73.3%-76.1%) compared to the scenario without ART. However, HIV mortality in 2014 was estimated to be 69% (95% CI: 46%-97%) higher in 2014 (161,000) if the model was calibrated only to HIV prevalence data. In the 2000-2014 period, the South African ART programme is estimated to have reduced the cumulative number of HIV deaths in adults by 1.72 million (95% CI: 1.58 million-1.84 million) and to have saved 6.15 million life years in adults (95% CI: 5.52 million-6.69 million). This compares with a potential saving of 8.80 million (95% CI: 7.90 million-9.59 million) life years that might have been achieved if South Africa had moved swiftly to implement WHO guidelines (2004-2013) and had achieved high levels of ART uptake in HIV-diagnosed individuals from 2004 onwards. The model is limited by its reliance on all-cause mortality data, given the lack of reliable cause-of-death reporting, and also does not allow for changes over time in tuberculosis control programmes and ART effectiveness.

CONCLUSIONS

ART has had a dramatic impact on adult mortality in South Africa, but delays in the rollout of ART, especially in the early stages of the ART programme, have contributed to substantial loss of life. This is the first study to our knowledge to calibrate a model of ART impact to population-level recorded death data in Africa; models that are not calibrated to population-level death data may overestimate HIV-related mortality.

New Biomedical Technologies and Strategies for Prevention of HIV and Other Sexually Transmitted Infections

Sexually transmitted infections remain to be of public health concern in many developing countries. Their control is important, considering the high incidence of acute infections, complications and sequelae, and their socioeconomic impact. This article discusses the new biomedical technologies and strategies for the prevention of HIV and other sexually transmitted infections.

Hesitance towards voluntary medical male circumcision in Lesotho: reconfiguring global health governance

Drawing on work examining HIV prevention initiatives in Lesotho, this paper considers the hesitation of national state actors towards the new strategy for HIV prevention - voluntary medical male circumcision (VMMC). Lesotho offers a representative case study on global health governance, given the country's high HIV burden and heavy dependence on foreign donor nations to implement local HIV prevention initiatives. In this paper, I use the case of VMMC opposition in Lesotho to examine how the new era of 'partnerships' has shifted the architecture of contemporary global health, specifically considering how global agreements are translated or negotiated into local practice. I argue that Lesotho's domestic policy-makers, in employing national statistics to assess if VMMC is an effective approach to addressing the local epidemic, are asserting a claim of expertise. In doing so, they challenge the traditional structures of global health politics, which have largely been managed by experts and funders from and in the global North. I explore the development of global VMMC policy, what drives Lesotho's resistance to comply, and consider the impact renegotiation efforts may have on future global health architecture.

Neonatal circumcision: is feeding behavior altered?

BACKGROUND

The effect of circumcision on feeding behavior in the newborn period is unknown. We hypothesized that circumcision would not have a significant effect on newborn feeding.

METHODS

This prospective study analyzed the effect of circumcision on neonatal feeding behavior. Inclusion criteria were healthy male infants WHO were exclusively bottle-fed and underwent a circumcision before discharge from the newborn nursery. We collected data (N = 42) on gestational age, birth weight, Apgar scores, maternal age, gravid status, anesthesia used during delivery, analgesia used after circumcision, time of circumcision, and volume and frequency of feeding before and after circumcision. Data were analyzed by using paired t tests, multivariable regression analysis, and analysis of variance (with SPSS version 18). Significance was P < .05 (2-tailed α).

RESULTS

Descriptive statistics for the entire group (N = 42) are as follows: mean ± SD gestational age: 38.7 ± 1.2 weeks; mean birth weight: 3.3 ± 0.4 kg; maternal age: 26.7 ± 6.3 years; baseline feeding (mean of first 2 feedings before circumcision): 24.5 ± 9.9 mL; mean first feeding after circumcision: 21.7 ± 11.9 mL; and mean second feeding: 26.7 ± 13.5 mL. Forty-eight percent of patients increased their feeding volume after circumcision compared with baseline, and 52% of patients decreased their feeding volume, which persisted with the second feeding. There was no statistical difference between the baseline and first feeding (P = .11) or second feeding (P = .22).

CONCLUSIONS

Our data suggest that circumcision does not alter feeding after circumcision. This information will be useful in counseling families regarding circumcision in the newborn period.

Male circumcision

Male circumcision consists of the surgical removal of some, or all, of the foreskin (or prepuce) from the penis. It is one of the most common procedures in the world. In the United States, the procedure is commonly performed during the newborn period. In 2007, the American Academy of Pediatrics (AAP) convened a multidisciplinary workgroup of AAP members and other stakeholders to evaluate the evidence regarding male circumcision and update the AAP's 1999 recommendations in this area. The Task Force included AAP representatives from specialty areas as well as members of the AAP Board of Directors and liaisons representing the American Academy of Family Physicians, the American College of Obstetricians and Gynecologists, and the Centers for Disease Control and Prevention. The Task Force members identified selected topics relevant to male circumcision and conducted a critical review of peer-reviewed literature by using the American Heart Association's template for evidence evaluation. Evaluation of current evidence indicates that the health benefits of newborn male circumcision outweigh the risks; furthermore, the benefits of newborn male circumcision justify access to this procedure for families who choose it. Specific benefits from male circumcision were identified for the prevention of urinary tract infections, acquisition of HIV, transmission of some sexually transmitted infections, and penile cancer. Male circumcision does not appear to adversely affect penile sexual function/sensitivity or sexual satisfaction. It is imperative that those providing circumcision are adequately trained and that both sterile techniques and effective pain management are used. Significant acute complications are rare. In general, untrained providers who perform circumcisions have more complications than well-trained providers who perform the procedure, regardless of whether the former are physicians, nurses, or traditional religious providers. Parents are entitled to factually correct, nonbiased information about circumcision and should receive this information from clinicians before conception or early in pregnancy, which is when parents typically make circumcision decisions. Parents should determine what is in the best interest of their child. Physicians who counsel families about this decision should provide assistance by explaining the potential benefits and risks and ensuring that parents understand that circumcision is an elective procedure. The Task Force strongly recommends the creation, revision, and enhancement of educational materials to assist parents of male infants with the care of circumcised and uncircumcised penises. The Task Force also strongly recommends the development of educational materials for providers to enhance practitioners' competency in discussing circumcision's benefits and risks with parents. The Task Force made the following recommendations:Evaluation of current evidence indicates that the health benefits of newborn male circumcision outweigh the risks, and the benefits of newborn male circumcision justify access to this procedure for those families who choose it. Parents are entitled to factually correct, nonbiased information about circumcision that should be provided before conception and early in pregnancy, when parents are most likely to be weighing the option of circumcision of a male child. Physicians counseling families about elective male circumcision should assist parents by explaining, in a nonbiased manner, the potential benefits and risks and by ensuring that they understand the elective nature of the procedure. Parents should weigh the health benefits and risks in light of their own religious, cultural, and personal preferences, as the medical benefits alone may not outweigh these other considerations for individual families. Parents of newborn boys should be instructed in the care of the penis, regardless of whether the newborn has been circumcised or not. Elective circumcision should be performed only if the infant's condition is stable and healthy. Male circumcision should be performed by trained and competent practitioners, by using sterile techniques and effective pain management. Analgesia is safe and effective in reducing the procedural pain associated with newborn circumcision; thus, adequate analgesia should be provided whenever newborn circumcision is performed.Nonpharmacologic techniques (eg, positioning, sucrose pacifiers) alone are insufficient to prevent procedural and postprocedural pain and are not recommended as the sole method of analgesia. They should be used only as analgesic adjuncts to improve infant comfort during circumcision. If used, topical creams may cause a higher incidence of skin irritation in low birth weight infants, compared with infants of normal weight; penile nerve block techniques should therefore be chosen for this group of newborns. Key professional organizations (AAP, the American Academy of Family Physicians, the American College of Obstetricians and Gynecologists, the American Society of Anesthesiologists, the American College of Nurse Midwives, and other midlevel clinicians such as nurse practitioners) should work collaboratively to:Develop standards of trainee proficiency in the performance of anesthetic and procedure techniques, including suturing; Teach the procedure and analgesic techniques during postgraduate training programs; Develop educational materials for clinicians to enhance their own competency in discussing the benefits and risks of circumcision with parents; Offer educational materials to assist parents of male infants with the care of both circumcised and uncircumcised penises. The preventive and public health benefits associated with newborn male circumcision warrant third-party reimbursement of the procedure. The American College of Obstetricians and Gynecologists has endorsed this technical report.

Scaling up circumcision programs in Southern Africa: the potential impact of gender disparities and changes in condom use behaviors on heterosexual HIV transmission

Circumcision significantly reduces female-to-male transmission of HIV infection, but changes in behavior may influence the overall impact on transmission. We sought to explore these effects, particularly for societies where women have less power to negotiate safe sex. We developed a compartmental epidemic model to simulate the population-level impact of various circumcision programs on heterosexual HIV transmission in Soweto. We incorporated gender-specific negotiation of condom use in sexual partnerships and explored post-circumcision changes in condom use. A 5-year prevention program in which only an additional 10% of uncircumcised males undergo circumcision each year, for example, would prevent 13% of the expected new HIV infections over 20 years. Outcomes were sensitive to potential changes in behavior and differed by gender. For Southern Africa, even modest programs offering circumcision would result in significant benefits. Because decreases in male condom use could diminish these benefits, particularly for women, circumcision programs should emphasize risk-reduction counseling.

Male circumcision for prevention of homosexual acquisition of HIV in men

BACKGROUND

Previous systematic reviews found inconsistent effects of male circumcision on HIV acquisition in men who have sex with men (MSM). However, a number of new studies have become available in the three years since the last systematic review.

OBJECTIVES

To assess the effects of male circumcision for preventing HIV acquisition by men through sex with men.

SEARCH STRATEGY

In June 2010 we electronically searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, AIDS Education Global Information System, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform; hand-searched reference lists of relevant articles; and contacted relevant organisations and experts. We updated the search in March 2011.

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs) and observational studies that assessed the effects of male circumcision on HIV acquisition in MSM.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility and methodological quality, and extracted data. We expressed study results as odds ratios (OR) with 95% confidence intervals (CI), and conducted random-effects meta-analysis.

MAIN RESULTS

We found no completed RCT and included 21 observational studies with 71,693 participants. The only eligible RCT is currently ongoing among MSM in China. The pooled effect estimate for HIV acquisition was not statistically significant (20 studies; 65,784 participants; OR 0.86, 95% CI 0.70 to 1.06) and showed significant heterogeneity (I²=53%). In a subgroup analysis, the results were statistically significant in studies of men reporting an insertive role (7 studies, 3465 participants; OR 0.27, 95% CI 0.17 to 0.44; I²=0%) but not in studies of men reporting a receptive role (3 studies, 1792 participants; OR 1.20, 95% CI 0.63 to 2.29; I² = 0%). There was no significant association between male circumcision and syphilis (8 studies; 34,999 participants: OR 0.96, 95% CI 0.82 to 1.13; I² = 0%), herpes simplex virus 1 (2 studies, 2740 participants; OR 0.90, 95% CI 0.53 to 1.52; I²=0%), or herpes simplex virus 2 (5 studies;10,285 participants; OR 0.86, 95% CI 0.62 to 1.21; I²=0%). The overall GRADE quality of evidence was low. None of the included studies assessed adverse effects associated with male circumcision.

AUTHORS' CONCLUSIONS

Current evidence suggests that male circumcision may be protective among MSM who practice primarily insertive anal sex, but the role of male circumcision overall in the prevention of HIV and other sexually transmitted infections among MSM remains to be determined. Therefore, there is not enough evidence to recommend male circumcision for HIV prevention among MSM at present. Further research should be of high quality and further explore interaction with the predominant sexual role.

Community-level gender equity and extramarital sexual risk-taking among married men in eight African countries

CONTEXT

In many parts of Africa, women are most likely to become infected with HIV by having unprotected sex with their husbands, who may have acquired the virus through extramarital sex. However, the ways in which aspects of community environments-particularly those related to gender equity-shape men's extramarital sexual risk-taking are not well understood.

METHODS

Demographic and Health Survey data from eight African countries (Chad, Ghana, Malawi, Nigeria, Tanzania, Uganda, Zambia and Zimbabwe) were used to examine associations between married men's engaging in risky extramarital sex (i.e., having had both unprotected sex and extramarital sex) and indicators of gender equity and other community characteristics. Separate multilevel logistic regression models that incorporated individual, household and community measures were created for each country.

RESULTS

In five countries, men who lived in communities with more equal ratios of women to men with at least a primary education were less likely to report risky extramarital sexual activity (odds ratios, 0.4-0.6). A similar relationship was found in four countries for the ratio of women to men who were employed (0.4-0.5). In three countries, men who lived in communities with more conservative attitudes toward wife-beating or male decision making had elevated odds of extramarital sexual risk-taking (1.1-1.5).

CONCLUSIONS

While HIV prevention programs should focus on reducing gender inequities, they also need to recognize the conservative cultural factors that influence the formation of men's masculine identities and, in turn, affect their sexual behavior.

Concurrent sexual partnerships do not explain the HIV epidemics in Africa: a systematic review of the evidence

The notion that concurrent sexual partnerships are especially common in sub-Saharan Africa and explain the region's high HIV prevalence is accepted by many as conventional wisdom. In this paper, we evaluate the quantitative and qualitative evidence offered by the principal proponents of the concurrency hypothesis and analyze the mathematical model they use to establish the plausibility of the hypothesis.We find that research seeking to establish a statistical correlation between concurrency and HIV prevalence either finds no correlation or has important limitations. Furthermore, in order to simulate rapid spread of HIV, mathematical models require unrealistic assumptions about frequency of sexual contact, gender symmetry, levels of concurrency, and per-act transmission rates. Moreover, quantitative evidence cited by proponents of the concurrency hypothesis is unconvincing since they exclude Demographic and Health Surveys and other data showing that concurrency in Africa is low, make broad statements about non-African concurrency based on very few surveys, report data incorrectly, report data from studies that have no information about concurrency as though they supported the hypothesis, report incomparable data and cite unpublished or unavailable studies. Qualitative evidence offered by proponents of the hypothesis is irrelevant since, among other reasons, there is no comparison of Africa with other regions.Promoters of the concurrency hypothesis have failed to establish that concurrency is unusually prevalent in Africa or that the kinds of concurrent partnerships found in Africa produce more rapid spread of HIV than other forms of sexual behaviour. Policy makers should turn attention to drivers of African HIV epidemics that are policy sensitive and for which there is substantial epidemiological evidence.

High GUD incidence in the early 20 century created a particularly permissive time window for the origin and initial spread of epidemic HIV strains

The processes that permitted a few SIV strains to emerge epidemically as HIV groups remain elusive. Paradigmatic theories propose factors that may have facilitated adaptation to the human host (e.g., unsafe injections), none of which provide a coherent explanation for the timing, geographical origin, and scarcity of epidemic HIV strains. Our updated molecular clock analyses established relatively narrow time intervals (roughly 1880-1940) for major SIV transfers to humans. Factors that could favor HIV emergence in this time frame may have been genital ulcer disease (GUD), resulting in high HIV-1 transmissibility (4-43%), largely exceeding parenteral transmissibility; lack of male circumcision increasing male HIV infection risk; and gender-skewed city growth increasing sexual promiscuity. We surveyed colonial medical literature reporting incidences of GUD for the relevant regions, concentrating on cities, suffering less reporting biases than rural areas. Coinciding in time with the origin of the major HIV groups, colonial cities showed intense GUD outbreaks with incidences 1.5-2.5 orders of magnitude higher than in mid 20(th) century. We surveyed ethnographic literature, and concluded that male circumcision frequencies were lower in early 20(th) century than nowadays, with low rates correlating spatially with the emergence of HIV groups. We developed computer simulations to model the early spread of HIV-1 group M in Kinshasa before, during and after the estimated origin of the virus, using parameters derived from the colonial literature. These confirmed that the early 20(th) century was particularly permissive for the emergence of HIV by heterosexual transmission. The strongest potential facilitating factor was high GUD levels. Remarkably, the direct effects of city population size and circumcision frequency seemed relatively small. Our results suggest that intense GUD in promiscuous urban communities was the main factor driving HIV emergence. Low circumcision rates may have played a role, probably by their indirect effects on GUD.

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

OBJECTIVE

The objective of this study is to estimate per-contact probability of HIV transmission in homosexual men due to unprotected anal intercourse (UAI) in the era of HAART.

DESIGN

Data were collected from a longitudinal cohort study of community-based HIV-negative homosexual men in Sydney, Australia.

METHODS

A total of 1427 participants were recruited from June 2001 to December 2004. They were followed up with 6-monthly detailed behavioral interviews and annual testing for HIV till June 2007. Data were used in a bootstrapping method, coupled with a statistical analysis that optimized a likelihood function for estimating the per-exposure risks of HIV transmission due to various forms of UAI.

RESULTS

During the study, 53 HIV seroconversion cases were identified. The estimated per-contact probability of HIV transmission for receptive UAI was 1.43% [95% confidence interval (CI) 0.48-2.85] if ejaculation occurred inside the rectum, and it was 0.65% (95% CI 0.15-1.53) if withdrawal prior to ejaculation was involved. The estimated transmission rate for insertive UAI in participants who were circumcised was 0.11% (95% CI 0.02-0.24), and it was 0.62% (95% CI 0.07-1.68) in uncircumcised men. Thus, receptive UAI with ejaculation was found to be approximately twice as risky as receptive UAI with withdrawal or insertive UAI for uncircumcised men and over 10 times as risky as insertive UAI for circumcised men.

CONCLUSION

Despite the fact that a high proportion of HIV-infected men are on antiretroviral treatment and have undetectable viral load, the per-contact probability of HIV transmission due to UAI is similar to estimates reported from developed country settings in the pre-HAART era.

Economic evaluations of adult male circumcision for prevention of heterosexual acquisition of HIV in men in sub-Saharan Africa: a systematic review

Background

There is conclusive evidence from observational data and three randomized controlled trials that circumcised men have a significantly lower risk of becoming infected with the human immunodeficiency virus (HIV). The aim of this study was to systematically review economic evaluations on adult male circumcision (AMC) for prevention of heterosexual acquisition of HIV in men.

Methods and Findings

Studies were identified from the following bibliographic databases: MEDLINE (Ovid), EMBASE (Ovid), Cochrane Library (Wiley's internet version), NHS EED and DARE Office of Health Economics HEED. The searches were conducted in November 2009. The Drummond 10-point checklist was used for methodological critique of the economic evaluations. Cost data were inflated and converted to 2008 US dollars (US$). Of 264 identified papers, only five met the inclusion criteria and were included in the review. The studies were published between 2006 and 2009. Most of the studies were carried out from the perspective of government healthcare payer. The time horizon ranged from 10 to 20 years. All studies reported that AMC is cost-effective. The reported cost per HIV infection averted ranged from US$174 to US$2808. The key driver of the cost-effectiveness models was circumcision efficacy.

Conclusions

All published economic evaluations offered the same conclusion that AMC is cost-effective and potentially cost-saving for prevention of heterosexual acquisition of HIV in men. On these grounds, AMC may be seen as a promising new form of strategy for prevention of HIV and should be implemented in conjunction with other evidence-based prevention methods.

Foreskin surface area and HIV acquisition in Rakai, Uganda (size matters)

INTRODUCTION

Male circumcision reduces HIV acquisition in men. We assessed whether foreskin surface area was associated with HIV acquisition prior to circumcision.

METHODS

In two randomized trials of male circumcision, the surface area of the foreskin was measured after surgery using standardized procedures. Nine hundred and sixty-five initially HIV-negative men were enrolled in a community cohort who subsequently enrolled in the male circumcision trials, provided 3920.8 person-years of observation prior to circumcision. We estimated HIV incidence per 100 person-years prior to circumcision, associated with foreskin surface area categorized into quartiles.

RESULTS

Mean foreskin surface area was significantly higher among men who acquired HIV (43.3 cm2, standard error 2.1) compared with men who remained uninfected (36.8 cm, standard error 0.5, P = 0.01). HIV incidence was 0.80/100 person-years (8/994.9 person-years) for men with foreskin surface areas in the lowest quartile (< or =26.3 cm2), 0.92/100 person-years (9/975.3 person-years) with foreskin areas in the second quartile (26.4-35.0 cm2), 0.90/100 person-years (8/888.5 person-years) with foreskin area in the third quartile (35.2-45.5 cm2) and 2.48/100 person-years (23/926.8 person-years) in men with foreskin surfaces areas in the highest quartile (>45.6 cm2). Compared with men with foreskin surface areas in the lowest quartile, the adjusted incidence rate ratio of HIV acquisition was 2.37 (95% confidence interval 1.05-5.31) in men with the largest quartile of foreskin surface area.

CONCLUSION

The risk of male HIV acquisition is increased among men with larger foreskin surface areas.

Heterosexual risk of HIV-1 infection per sexual act: systematic review and meta-analysis of observational studies

We did a systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact. 43 publications comprising 25 different study populations were identified. Pooled female-to-male (0.04% per act [95% CI 0.01-0.14]) and male-to-female (0.08% per act [95% CI 0.06-0.11]) transmission estimates in high-income countries indicated a low risk of infection in the absence of antiretrovirals. Low-income country female-to-male (0.38% per act [95% CI 0.13-1.10]) and male-to-female (0.30% per act [95% CI 0.14-0.63]) estimates in the absence of commercial sex exposure (CSE) were higher. In meta-regression analysis, the infectivity across estimates in the absence of CSE was significantly associated with sex, setting, the interaction between setting and sex, and antenatal HIV prevalence. The pooled receptive anal intercourse estimate was much higher (1.7% per act [95% CI 0.3-8.9]). Estimates for the early and late phases of HIV infection were 9.2 (95% CI 4.5-18.8) and 7.3 (95% CI 4.5-11.9) times larger, respectively, than for the asymptomatic phase. After adjusting for CSE, presence or history of genital ulcers in either couple member increased per-act infectivity 5.3 (95% CI 1.4-19.5) times versus no sexually transmitted infection. Study estimates among non-circumcised men were at least twice those among circumcised men. Low-income country estimates were more heterogeneous than high-income country estimates, which indicates poorer study quality, greater heterogeneity of risk factors, or under-reporting of high-risk behaviour. Efforts are needed to better understand these differences and to quantify infectivity in low-income countries.

Transmission probabilities of HIV and herpes simplex virus type 2, effect of male circumcision and interaction: a longitudinal study in a township of South Africa

OBJECTIVES

A synergy between HIV and herpes simplex virus type 2 (HSV-2) infections has been reported in observational studies. The objectives of this study were to estimate the per-sex-act female-to-male transmission probabilities (FtoMTPs) of HIV and HSV-2, the effect of each infection on the FtoMTP of the other and the effect of male circumcision on these FtoMTPs.

DESIGN

We used longitudinal data collected during the male circumcision trial conducted in Orange Farm (South Africa).

METHODS

Results were obtained by specific mathematical modeling of HIV and HSV-2 statuses of the men as functions of their sexual behavior and male circumcision status. The model took into account an estimation of the HIV and HSV-2 statuses of each of their female partners. Confidence intervals (CI) were estimated using a bootstrap resampling method.

RESULTS

The HIV and HSV-2 FtoMTPs, during an unprotected sexual contact for an uncircumcised male in the absence of the other virus in both partners, were 0.0047 (95% CI: 0.0014-0.017) and 0.0067 (95% CI: 0.0028-0.014), respectively. HSV-2 in either partner increased HIV FtoMTP with a relative risk (RR) of 3.0 (95% CI: 1.01-7.3). Conversely, HIV in either partner increased HSV-2 FtoMTP (RR= 2.5; 95% CI: 1.1- 6.3). Male circumcision significantly decreased these probabilities with RRs of 0.24 (95% CI: 0.11-0.44) and 0.59 (95% CI: 0.36-0.91), respectively.

CONCLUSION

This study gave the first estimates of HSV-2 per-sex-act FtoMTPs in Africa. It demonstrated a synergy between HIV and HSV-2 infections and a protective effect of male circumcision on HSV-2 acquisition by males.

Biomedical interventions to prevent HIV infection: evidence, challenges, and way forward

Intensive research efforts for more than two decades have not yet resulted in an HIV vaccine of even moderate effectiveness. However, some progress has been made with other biomedical interventions, albeit on the basis of inconsistent levels of evidence. The male condom, if used correctly and consistently, has been proven in observational studies to be very effective in blocking HIV transmission during sexual intercourse; and, in three randomised trials, male circumcision was protective against HIV acquisition among men. Treatment of sexually transmitted infections, a public health intervention in its own right, has had mixed results, depending in part on the epidemic context in which the approach was assessed. Finally, oral and topical antiretroviral compounds are being assessed for their role in reduction of HIV transmission during sexual intercourse. Research on biomedical interventions poses formidable challenges. Difficulties with product adherence and the possibility of sexual disinhibition are important concerns. Biomedical interventions will need to be part of an integrative package that includes biomedical, behavioural, and structural interventions. Assessment of such multicomponent approaches with moderate effects is difficult. Issues to be considered include the nature of control groups and the effect of adherence on the true effectiveness of the intervention.

Rethinking the heterosexual infectivity of HIV-1: a systematic review and meta-analysis

Studies of cumulative HIV incidence suggest that cofactors such as genital ulcer disease, HIV disease stage, and male circumcision influence HIV transmission; however, the heterosexual infectivity of HIV-1 is commonly cited as a fixed value (approximately 0.001, or one transmission per 1000 contacts). We sought to estimate transmission cofactor effects on the heterosexual infectivity of HIV-1 and to quantify the extent to which study methods have affected infectivity estimates. We undertook a systematic search (up to April 27, 2008) of PubMed, Web of Science, and relevant bibliographies to identify articles estimating the heterosexual infectivity of HIV-1. We used meta-regression and stratified random-effects meta-analysis to assess differences in infectivity associated with cofactors and study methods. Infectivity estimates were very heterogeneous, ranging from zero transmissions after more than 100 penile-vaginal contacts in some serodiscordant couples to one transmission for every 3.1 episodes of heterosexual anal intercourse. Estimates were only weakly associated with study methods. Infectivity differences, expressed as number of transmissions per 1000 contacts, were 8.1 (95 % CI 0.4-15.8) when comparing uncircumcised to circumcised susceptible men, 6.0 (3.3-8.8) comparing susceptible individuals with and without genital ulcer disease, 1.9 (0.9-2.8) comparing late-stage to mid-stage index cases, and 2.5 (0.2-4.9) comparing early-stage to mid-stage index cases. A single value for the heterosexual infectivity of HIV-1 fails to reflect the variation associated with important cofactors. The commonly cited value of 0.001 was estimated among stable couples with low prevalences of high-risk cofactors, and represents a lower bound. Cofactor effects are important to include in epidemic models, policy considerations, and prevention messages.

Neonatal circumcision: effects on breastfeeding and outcomes associated with breastfeeding

AIM

There have been recurrent claims made that neonatal circumcision disrupts the development and maintenance of breastfeeding in infants. The aim of the current study was to use a longitudinal birth cohort study to examine the associations between neonatal circumcision status and both breastfeeding outcomes, and health and cognitive ability outcomes associated with breastfeeding.

METHOD

Data were obtained from the Christchurch Health and Development Study, a longitudinal study of over 1000 individuals born in Christchurch New Zealand in mid 1977. Data were obtained for male cohort members (n = 635) on circumcision status, breastfeeding outcomes, health outcomes in infancy and cognitive ability outcomes later in life.

RESULTS

Circumcision status was not significantly associated (P > 0.05) with breastfeeding outcomes in infancy, even following adjustment for covariate factors, including maternal age, family socio-economic status, ethnicity and birthweight. Also, circumcision status was not significantly associated (P > 0.05) with health in infancy and cognitive ability outcomes in later childhood, even after adjustment for covariate factors.

CONCLUSIONS

There was no evidence of an association between neonatal circumcision status and breastfeeding outcomes, or between circumcision status and health and cognitive ability outcomes associated with breastfeeding, and the findings do not support the view that neonatal circumcision disrupts breastfeeding.

Predicting the impact of a partially effective HIV vaccine and subsequent risk behavior change on the heterosexual HIV epidemic in low- and middle-income countries: A South African example

We developed a mathematical model to simulate the impact of various partially effective preventive HIV vaccination scenarios in a population at high risk for heterosexually transmitted HIV. We considered an adult population defined by gender (male/female), disease stage (HIV-negative, HIV-positive, AIDS, and death), and vaccination status (unvaccinated/vaccinated) in Soweto, South Africa. Input data included initial HIV prevalence of 20% (women) and 12% (men), vaccination coverage of 75%, and exclusive male negotiation of condom use. We explored how changes in vaccine efficacy and postvaccination condom use would affect HIV prevalence and total HIV infections prevented over a 10-year period. In the base-case scenario, a 40% effective HIV vaccine would avert 61,000 infections and reduce future HIV prevalence from 20% to 13%. A 25% increase (or decrease) in condom use among vaccinated individuals would instead avert 75,000 (or only 46,000) infections and reduce the HIV prevalence to 12% (or only 15%). Furthermore, certain combinations of increased risk behavior and vaccines with <43% efficacy could worsen the epidemic. Even modestly effective HIV vaccines can confer enormous benefits in terms of HIV infections averted and decreased HIV prevalence. However, programs to reduce risk behavior may be important components of successful vaccination campaigns.

Global epidemiology of HIV-AIDS

Although intravenous drug use is the major route of transmission in several countries, sexual transmission is the dominant mode of HIV spread globally, with a concomitant epidemic in infants borne to HIV-infected mothers. The HIV epidemic varies substantially from one geographic area to another, and three broad epidemic categories describe the diversity of features observed globally: low epidemic settings, centrzated epidemics, and generalized epidemics. The introduction of highly active antiretroviral therapy in industrialized countries has transformed AIDS from an inevitably fatal condition to a chronic, treatable condition, but this goal has yet to be realized in most resource-constrained settings that bear a disproportionate burden of infection. This article describes the modes of HIV transmission, geographic distribution of the evolving AIDS pandemic, and case studies of each of the three types of HIV epidemics, and presents global trends in AIDS and mortality.

Men's circumcision status and women's risk of HIV acquisition in Zimbabwe and Uganda

OBJECTIVE

To assess whether male circumcision of the primary sex partner is associated with women's risk of HIV.

DESIGN

Data were analyzed from 4417 Ugandan and Zimbabwean women participating in a prospective study of hormonal contraception and HIV acquisition. Most were recruited from family planning clinics; some in Uganda were referred from higher-risk settings such as sexually transmitted disease clinics.

METHODS

Using Cox proportional hazards models, time to HIV acquisition was compared for women with circumcised or uncircumcised primary partners. Possible misclassification of male circumcision was assessed using sensitivity analysis.

RESULTS

At baseline, 74% reported uncircumcised primary partners, 22% had circumcised partners and 4% had partners of unknown circumcision status. Median follow-up was 23 months, during which 210 women acquired HIV (167, 34, and 9 women whose primary partners were uncircumcised, circumcised, or of unknown circumcision status, respectively). Although unadjusted analyses indicated that women with circumcised partners had lower HIV risk than those with uncircumcised partners, the protective effect disappeared after adjustment for other risk factors [hazard ratio (HR), 1.03; 95% confidence interval (CI), 0.69-1.53]. Subgroup analyses suggested a non-significant protective effect of male circumcision on HIV acquisition among Ugandan women referred from higher-risk settings: adjusted HR 0.16 (95% CI, 0.02-1.25) but little effect in Ugandans (HR, 1.33; 95% CI, 0.72-2.47) or Zimbabweans (HR, 1.12; 95% CI, 0.65-1.91) from family planning clinics.

CONCLUSIONS

After adjustment, male circumcision was not significantly associated with women's HIV risk. The potential protection offered by male circumcision for women recruited from high-risk settings warrants further investigation.

The Protective Effect of Circumcision on HIV Incidence in Rural Low-Risk Men Circumcised Predominantly by Traditional Circumcisers in Kenya

BACKGROUND

Three randomized controlled trials (RCTs) have demonstrated that male circumcision prevents female-to-male HIV transmission in sub-Saharan Africa. Data from prospective cohort studies are helpful in considering generalizability of RCT results to populations with unique epidemiologic/cultural characteristics.

METHODS

Prospective observational cohort sub-analysis. A total of 1378 men were evaluated after 2 years of follow-up. Baseline sociodemographic and behavioral/HIV risk characteristics were compared between 270 uncircumcised and 1108 circumcised men. HIV incidence rates (per 100 person-years) were calculated, and Cox proportional hazards regression analyses estimated hazard rate ratios (HRs).

RESULTS

Of the men included in this study, 80.4% were circumcised; 73.9% were circumcised by traditional circumcisers. Circumcision was associated with tribal affiliation, high school education, fewer marriages, and smaller age difference between spouses (P < 0.05). After 2 years of follow-up, there were 30 HIV incident cases (17 in circumcised and 13 in uncircumcised men). Two-year HIV incidence rates were 0.79 (95% confidence interval [CI]: 0.46 to 1.25) for circumcised men and 2.48 (95% CI: 1.33 to 4.21) for uncircumcised men corresponding to a HR = 0.31 (95% CI: 0.15 to 0.64). In one model controlling for sociodemographic factors, the HR increased and became non-significant (HR = 0.55; 95% CI: 0.20 to 1.49).

CONCLUSIONS

Circumcision by traditional circumcisers offers protection from HIV infection in adult men in rural Kenya. Data from well-designed prospective cohort studies in populations with unique cultural characteristics can supplement RCT data in recommending public health policy.

The influence of hormonal contraceptive use on HIV-1 transmission and disease progression

Women account for nearly one-half of new human immunodeficiency virus type 1 (HIV-1) infections worldwide, including the majority of infections in Africa. Biological and epidemiological studies suggest that hormonal contraceptive use could influence susceptibility to HIV-1, as well as infectivity and disease progression for those who become infected. However, not all studies have shown this relationship, and many questions remain. Safe and effective contraceptive choices are essential for women with and at risk for HIV-1 infection. Thus, understanding the effect, if any, of hormonal contraception on HIV-1 disease among women is a public health priority.

Circumcision and HIV transmission

PURPOSE OF REVIEW

To review the recent literature on male circumcision and its effect on HIV acquisition.

RECENT FINDINGS

The report from the randomized clinical trial of male circumcision in South Africa demonstrating a 60% protective effect in preventing HIV acquisition provided the first clinical trial evidence of efficacy of male circumcision in protecting men against HIV infection. This protective effect was consistent with both ecological and epidemiologic studies which also show a protective effect of 50-70% in men at high risk for HIV infection. Biological studies also demonstrate an increased number of HIV receptor cells in the mucosa of foreskin providing additional evidence of HIV susceptibility in the uncircumcised male. Male circumcision may also have a beneficial effect in preventing HIV acquisition in women and lowering selected sexually transmitted infections in both sexes.

SUMMARY

The results of two ongoing randomized clinical trials of male circumcision in Kenya and Uganda are awaited with interest, however male circumcision should be carefully considered as a potential public health tool in preventing HIV acquisition. If other trials confirm the results of the South African trial, implementation of this surgical procedure will need to be carefully scaled up and integrated into other prevention programs with emphasis on surgical training, aseptic techniques, acceptability, availability and cultural considerations.

Male circumcision as a preventive measure against HIV and other sexually transmitted diseases

PURPOSE OF REVIEW

In 2005, 4.1 million people were infected with HIV. There is an urgent need to intensify and expand HIV prevention methods. Male circumcision is one of several potential approaches. This review summarizes recent evidence for the potential of male circumcision to prevent HIV and other sexually transmitted infections.

RECENT FINDINGS

The first randomized controlled trial of adult male circumcision found a highly significant 60% reduction in HIV incidence among men in the intervention arm. Modelling this effect predicts that widespread implementation of male circumcision could avert 2 million HIV infections over the next decade in sub-Saharan Africa. The biological rationale is that the foreskin increases risk of HIV infection due to the high density of HIV target cells and lack of keratinization of the inner mucosal surface.

SUMMARY

There is strong evidence that male circumcision reduces risk of HIV, syphilis and chancroid. If results are confirmed by two ongoing trials in sub-Saharan Africa, provision of safe male circumcision could be added to HIV prevention packages in high-incidence settings. This would also provide an opportunity for HIV-prevention education and counselling to young men at high risk of infection.

The impact of male circumcision on HIV incidence and cost per infection prevented: a stochastic simulation model from Rakai, Uganda

OBJECTIVES

To estimate the impact of male circumcision on HIV incidence, the number of procedures per HIV infection averted, and costs per infection averted.

METHODS

A stochastic simulation model with empirically derived parameters from a cohort in Rakai, Uganda was used to estimate HIV incidence, assuming that male circumcision reduced the risks of HIV acquisition with rate ratios (RR) ranging from 0.3 to 0.6 in men, their female partners, and in both sexes combined, with circumcision coverage 0-100%. The reproductive number (R0) was also estimated. The number of HIV infections averted per circumcision was estimated from the incident cases in the absence of surgery minus the projected number of incident cases over 10 years following circumcision. The cost per procedure ($69.00) was used to estimate the cost per HIV infection averted.

RESULTS

Baseline HIV incidence was 1.2/100 person-years. Male circumcision could markedly reduce HIV incidence in this population, particularly if there was preventative efficacy in both sexes. Under many scenarios, with RR < or = 0.5, circumcision could reduce R0 to < 1.0 and potentially abort the epidemic. The number of surgeries per infection averted over 10 years was 19-58, and the costs per infection averted was $1269-3911, depending on the efficacy of circumcision for either or both sexes, assuming 75% service coverage. However, behavioral disinhibition could offset any benefits of circumcision.

CONCLUSION

Male circumcision could have substantial impact on the HIV epidemic and provide a cost-effective prevention strategy if benefits are not countered by behavioral disinhibition.

Plausible and implausible parameters for mathematical modeling of nominal heterosexual HIV transmission

PURPOSE

Several mathematical models simulate a HIV/AIDS epidemic by using the assumption that heterosexual transmission is the major or sole transmission mode. The validity of these models has been unclear. To understand the validity of these models, empirical estimates for relevant model parameters are needed that can be compared with parameters used in mathematical models.

METHODS

A brief review of per-contact transmission probabilities based on HIV-discordant, monogamous couples is provided, and sources of bias in transmission efficiency estimates are discussed. Average number of partnerships and the distribution of partnerships are estimated for seven sub-Saharan African countries. Distribution parameters are fitted to the Poisson distribution, negative binomial distribution, and the discrete Pareto (Zipf) distribution, using the maximum likelihood method. The Pearson chi2 test statistic is used to measure goodness of fit, and the Akaike and Bayesian information criteria are also provided. To balance the reported number of partnerships, missing number of prostitutes is estimated. These empirical estimates for relevant model parameters are compared with parameters used in representative models of nominal heterosexual HIV transmission in Africa.

RESULTS

Reported transmission efficiencies (unadjusted for competing exposures that inflate estimates) per sexual episode range from 0.0003 to 0.0012. Average number of partnerships is less than 1.5 in all countries. The discrete Pareto distribution fits the data better than the Poisson or negative binominal distribution. In almost all countries, female reported number of partners follows a discrete Pareto distribution. To close the sex disparity gap in number of partnerships, between 0.13% and 0.69% of the female population would need to be classified as prostitutes. Comparing these estimates with the parameter values used in existing mathematical models shows that existing models use grossly inflated per contact transmission efficiencies or rely on implausible assumptions regarding contact frequency, which results in implausibly high per-partner transmission rates. Assumptions regarding average number of partners are too high, and the distribution of partnerships is not supported by available data. As a consequence, existing mathematical models overestimate nominally heterosexually transmitted HIV infection in sub-Saharan Africa.

CONCLUSIONS

Existing models of nominal heterosexual HIV transmission for sub-Saharan Africa rely on assumptions inconsistent with empirical evidence. Simulations have not accurately portrayed the epidemiological situation in sub-Saharan Africa, and conclusions drawn from these models should be interpreted with great caution. To realistically simulate HIV spread in sub-Saharan Africa's general population nominally due to heterosexual HIV transmission, parameter values should be based on the most accurate data.

Modelling the public health impact of male circumcision for HIV prevention in high prevalence areas in Africa

Background

Recent clinical trials in Africa, in combination with several observational epidemiological studies, have provided evidence that male circumcision can reduce HIV female-to-male transmission risk by 60% or more. However, the public health impact of large-scale male circumcision programs for HIV prevention is unclear.

Methods

Two mathematical models were examined to explore this issue: a random mixing model and a compartmental model that distinguishes risk groups associated with sex work. In the compartmental model, two scenarios were developed, one calculating HIV transmission and prevalence in a context similar to the country of Botswana, and one similar to Nyanza Province, in western Kenya.

Results

In both models, male circumcision programs resulted in large and sustained declines in HIV prevalence over time among both men and women. Men benefited somewhat more than women, but prevalence among women was also reduced substantially. With 80% male circumcision uptake, the reductions in prevalence ranged from 45% to 67% in the two "countries", and with 50% uptake, from 25% to 41%. It would take over a decade for the intervention to reach its full effect.

Conclusion

Large-scale uptake of male circumcision services in African countries with high HIV prevalence, and where male circumcision is not now routinely practised, could lead to substantial reductions in HIV transmission and prevalence over time among both men and women.

Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial

BACKGROUND

Ecological and observational studies suggest that male circumcision reduces the risk of HIV acquisition in men. Our aim was to investigate the effect of male circumcision on HIV incidence in men.

METHODS

4996 uncircumcised, HIV-negative men aged 15-49 years who agreed to HIV testing and counselling were enrolled in this randomised trial in rural Rakai district, Uganda. Men were randomly assigned to receive immediate circumcision (n=2474) or circumcision delayed for 24 months (2522). HIV testing, physical examination, and interviews were repeated at 6, 12, and 24 month follow-up visits. The primary outcome was HIV incidence. Analyses were done on a modified intention-to-treat basis. This trial is registered with ClinicalTrials.gov, with the number NCT00425984.

FINDINGS

Baseline characteristics of the men in the intervention and control groups were much the same at enrollment. Retention rates were much the same in the two groups, with 90-92% of participants retained at all time points. In the modified intention-to-treat analysis, HIV incidence over 24 months was 0.66 cases per 100 person-years in the intervention group and 1.33 cases per 100 person-years in the control group (estimated efficacy of intervention 51%, 95% CI 16-72; p=0.006). The as-treated efficacy was 55% (95% CI 22-75; p=0.002); efficacy from the Kaplan-Meier time-to-HIV-detection as-treated analysis was 60% (30-77; p=0.003). HIV incidence was lower in the intervention group than it was in the control group in all sociodemographic, behavioural, and sexually transmitted disease symptom subgroups. Moderate or severe adverse events occurred in 84 (3.6%) circumcisions; all resolved with treatment. Behaviours were much the same in both groups during follow-up.

INTERPRETATION

Male circumcision reduced HIV incidence in men without behavioural disinhibition. Circumcision can be recommended for HIV prevention in men.

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.

Epidemiology of HIV-1 Infection in Agricultural Plantation Residents in Kericho, Kenya

A cross-sectional study was performed to determine the prevalence and risk factors for HIV-1 infection among agricultural plantation residents in Kericho, Kenya. Volunteers were recruited, interviewed, and phlebotomized for HIV-1 serologic testing. Sex-specific adjusted odds ratios were estimated using logistic regression. The overall HIV-1 prevalence was 9.9% (81/820), with prevalence in women more than twice that in men (17.4% vs 8.0%, P=0.001). Among men, elevated HIV-1 prevalence was seen with increasing age, peaking in those older than 30 years (10.3%), marriage (10.4%), Luo tribe affiliation (23.5%), employment (8.9%), travel (11.0%), and being uncircumcised (29.2%). Among women, elevated HIV-1 prevalence was seen in those with no formal education (36.8%) and those who received goods in exchange for sex (36.0%). More than 97% of volunteers expressed a willingness to participate in future HIV-1 studies requiring semiannual visits. HIV prevention efforts have been implemented, along with further research to characterize this population for future cohort feasibility studies and HIV-1 vaccine efficacy trials.

Estimation of the sexual transmission of HIV in Kenya and Uganda on the trans-Africa highway: the continuing role for prevention in high risk groups

OBJECTIVE

To explore the effect of transactional sex on the trans-Africa highway from Mombasa-Kampala in contributing to the HIV epidemic and the impact that an effective prevention intervention could have.

METHODS

Variables for input into a simple model of HIV prevention, AVERT, were derived from a study of hot spots of transactional sex on the trans-Africa highway. Diaries were completed by a sample of sex workers at selected sites of transactional sex for a period of 28 consecutive days. Key information elicited included numbers, types and occupations of clients, numbers of liaisons, sexual acts in each liaison, and condom use. 857 diaries were distributed and 578 received and usable in 30 sites. A sexual patterning matrix was completed by 202 truckers at the Malaba border point as part of a health seeking behaviour survey. Two methods were employed to estimate female sex worker (FSW) numbers on the highway. FSW focus group discussions (FGDs) at 15 sites were carried out and included questioning on the number of sex workers at the site. As most transactional sex on the highway is centred on bars and lodgings, a patron census and survey of 1007 bars and lodgings was carried out which included questions on the presence and proportions of FSWs among the clientele.

RESULTS

There are an estimated 8000 FSWs on the trans-Africa highway from Mombasa to Kampala. Annual numbers of different sexual partners per FSW were 129, annual numbers of sexual acts per FSW were 634, percentage of sexual acts protected by condom use was 77.7%. Using these input data an estimated 3200-4148 new HIV infections occur on this portion of the trans-Africa highway in 1 year. Having a 90% condom use programme in place could prevent almost two thirds of these infections and cumulative incidence would decline from 1.29% to 0.42%.

CONCLUSIONS

In generalised epidemics there has been a debate as to the place of targeted interventions. In the current east African epidemic we show that a targeted intervention could have significant impact in averting HIV infections related to the trans-Africa highway.

Mapping transactional sex on the Northern Corridor highway in Kenya

Even in generalized HIV/AIDS epidemics, vulnerable populations such as sex workers and truckers require special attention in programming. Combining a number of elicitation methods, centred on Geographical Information Systems (GIS) mapping, the Kenyan section of the Northern Corridor highway was studied to characterize the 'hot spots' where transactional sex is concentrated and to provide estimates of numbers of truckers and sex workers and the volumes of transactional sex taking place on the highway. An average of 2400 trucks park overnight at the 39 hot spots identified. These spots have an estimated sex worker population of 5600 women. Analysis of 403 sex worker diaries shows an average of 13.6 different clients and 54.2 sex acts in a month. Condom use is 69% in liaisons with regular clients and 90% with casual clients. The use of GIS is demonstrated at regional and local scales. The 'bridge population' of clients of sex workers, containing a wide rage of occupations, supports the concept of programming for 'vulnerable places' as well as vulnerable groups.

Risk of HIV-1 transmission for parenteral exposure and blood transfusion: a systematic review and meta-analysis

BACKGROUND

The role of iatrogenic transmission within the HIV/AIDS pandemic remains contentious. Estimates of the risk of HIV transmission from injections and blood transfusions are required to inform appropriate prevention policy.

OBJECTIVES

Systematic review and meta-analysis of the literature on HIV-1 infectivity for parenteral transmission and blood transfusion.

REVIEW METHODS

All identified studies with relevant transmission probability estimates up to May 2005 were included.

STATISTICAL METHODS

When appropriate, summary estimates for accidental percutaneous and blood product exposures were derived.

RESULTS

Infectivity estimates following a needlestick exposure ranged from 0.00 to 2.38% [weighted mean, 0.23%; 95% confidence interval (CI), 0.00-0.46%; n = 21]. Three estimates of infectivity per intravenous drug injection ranged from 0.63 to 2.4% (median, 0.8%); a summary estimate could not be calculated. The quality of the only estimate of infectivity per contaminated medical injection (1.9-6.9%) was assessed. Instead we propose a range of 0.24-0.65%. Infectivity estimates for confirmed contaminated blood transfusions range from 88.3 to 100.0% (weighted mean, 92.5%; 95% CI, 89.0-96.1%; n = 6).

CONCLUSIONS

Infectivity estimates for infected blood transfusions are larger than for other modes of HIV transmission. Few studies on transmission risk per contaminated injection were found. However, transmission risk per needlestick injury, where needles are more likely to be rinsed or disinfected between recipients (especially for medical injections), may be representative of non-intravenous medical injections and lower than the risk from intravenous injections, which are likely to be deeper and to involve more fluids. Further work is needed to better estimate transmission probability related to contaminated injections and its likely contribution to overall HIV transmission.