Effect of herpes simplex suppression on incidence of HIV among women in Tanzania

Modelling the interactions between herpes simplex virus type 2 and HIV: implications for the HIV epidemic in southern India

BACKGROUND

The role of herpes simplex virus type 2 (HSV-2) in the HIV epidemic and the potential impact of HSV-2 suppressive therapy have previously been explored only within the context of sub-Saharan Africa. In this analysis, modelling is used to estimate the contribution of HSV-2 to HIV transmission from clients to female sex workers (FSW) in a southern Indian setting and the maximum potential impact of 'perfect' HSV-2 suppressive therapy on HIV incidence.

METHODS

A dynamic HSV-2/HIV model was developed, parameterised and fitted to Mysore data. The model estimated the attributable fractions of HIV infections due to HSV-2. Multivariate sensitivity analyses and regression analyses were conducted.

RESULTS

The model suggests that 36% (95% CI 22% to 62%) of FSW HIV infections were due to HSV-2, mostly through HSV-2 asymptomatic shedding. Even if HSV-2 suppressive therapy could eliminate the effect of HSV-2 on HIV infectivity among all co-infected clients, only 15% (95% CI 3% to 41%) of HIV infections among FSW would have been averted. 36% (95% CI 18% to 61%) of HIV infections among HSV-2-infected FSW could have been averted if suppressive therapy reduced their risk of HIV acquisition to that of HSV-2-uninfected FSW.

CONCLUSIONS

HSV-2 contributes substantially to HIV in this southern Indian context. However, even in the best case scenario, HSV-2 suppressive therapy is unlikely to reduce HIV transmission or acquisition by more than 50% (as aimed for in recent trials), because of the limited strength of the interaction effect between HSV-2 and HIV.

Pre-exposure prophylaxis state of the science: empirical analogies for research and implementation

Pre-exposure prophylaxis (PrEP) has the potential to become a powerful biomedical approach to HIV prevention; however, its success depends on behavioral and social factors that may determine its appropriate use. This article is designed to facilitate interdisciplinary empirical analogies relevant to PrEP implementation, reviewing behavioral and social science findings that may provide lessons critical to the success of PrEP as a biomedical-behavioral prevention strategy. As we prepare for the dissemination of new biomedical approaches to HIV prevention, integrating the state of the science across disciplines may result in innovative strategies for implementation that can enhance their success.

Postexposure prophylaxis, preexposure prophylaxis or universal test and treat: the strategic use of antiretroviral drugs to prevent HIV acquisition and transmission

This review considers the use of antiretroviral drugs specifically to prevent HIV transmission. Antiretroviral therapy (ART) can be implemented for the protection of uninfected individuals both before (preexposure prophylaxis) and after (postexposure prophylaxis) exposure to HIV infection. Preexposure prophylaxis may be used coitally dependently when individuals are intermittently exposed or by continuous daily dosing for those constantly exposed; postexposure prophylaxis is used in 28-day courses. Alternatively, ART can be used strategically to reduce the viral load and consequent infectiousness of an HIV-infected individual, thereby limiting the risk of onward viral transmission. A policy of universal HIV testing to enhance the identification of all HIV-positive individuals followed by immediate treatment of all HIV-positive individuals, irrespective of their CD4 cell counts (universal test and treat), has been postulated as a potential tool capable of reducing HIV incidence at a population level. This concept represents a paradigm shift in the use of ART, targeting infectious individuals for prevention rather than protecting uninfected exposed populations. This strategy could have the advantage of preventing transmission and reducing HIV incidence at a population level, as well as delivering universal access to therapy for all people living with HIV and AIDS, potentially eliminating mother-to-child HIV transmission and limiting concomitant diseases such as tuberculosis. This review critically examines the scientific basis of ART for HIV prevention, summarizing the risks and opportunities of the potential expansion of ART for prevention. Specifically, we consider the evidences for and against targeting HIV-uninfected individuals compared with enhanced HIV testing and treatment of HIV-infected individuals in terms of impact on viral transmission.

Use of acyclovir for suppression of human immunodeficiency virus infection is not associated with genotypic evidence of herpes simplex virus type 2 resistance to acyclovir: analysis of specimens from three phase III trials

Herpes simplex virus type 2 (HSV-2) is the most common cause of genital ulcer disease and is a cofactor for HIV-1 acquisition and transmission. We analyzed specimens from three separate phase III trials of acyclovir (ACV) for prevention of HIV-1 acquisition and transmission to determine if failure of ACV to interrupt HIV acquisition and transmission was associated with genotypic ACV resistance. Acyclovir (400 mg twice daily) or placebo was provided to HSV-2-infected persons at risk of HIV-1 infection in the Mwanza and HPTN 039 trials and to persons dually infected with HSV-2 and HIV-1 who had an HIV-negative partner in the Partners in Prevention study. We extracted HSV DNA from genital ulcer swabs or cervicovaginal lavage fluids from 68 samples obtained from 64 participants randomized to ACV and sequenced the HSV-2 UL23 gene encoding thymidine kinase. The UL23 sequences were compared with published and unpublished data. Variants were observed in 38/1,128 (3.4%) nucleotide positions in the UL23 open reading frame, with 58% of these encoding amino acid changes. No deletions, insertions, or mutations known to be associated with resistance were detected. Thirty-one of the variants (81.5%) are newly reported, 15 of which code for amino acid changes. Overall, UL23 is highly polymorphic compared to other loci in HSV-2, but no drug resistance mutations were detected that could explain the failure to reduce HIV incidence or to prevent HIV-1 transmission in these studies.

Treatment of sexually transmitted infections for HIV prevention: end of the road or new beginning?

Observational and biological data provide compelling evidence of the importance of sexually transmitted infections (STIs) in HIV transmission, but only one of nine intervention trials has shown an effect. This article reviews the observational studies, critically examines the nine randomized controlled trials evaluating the impact of STI treatment interventions on HIV incidence, and discusses implications for HIV prevention policy, programs and future research. The role of other vaginal infections is also briefly considered. In aggregate, the evidence strongly supports the concept that STI treatment prevents HIV infection. However, issues in trial design and conduct, including HIV epidemic phase, STI prevalence, intervention in comparison groups, and power have affected five of the six trials of treatment of curable STIs. In the three herpes intervention trials, antivirals for HSV suppression were insufficiently potent to alleviate persistent genital inflammation in HIV-negative HSV2-positive persons, and the reduction in HIV levels in HIV-positive persons was insufficient to reduce HIV transmission. It is time for a new phase of exploration of how, when, and in whom to include STI control as a key component of HIV prevention, driven by basic research to elucidate the mechanisms by which STIs and vaginal infections facilitate HIV transmission. From a policy perspective, treatment of curable STIs is an essential part of primary healthcare and is a cheap, simple, and effective intervention when appropriately targeted and delivered. It should be promoted as an essential component of HIV control programs in communities in which the burden of STIs is substantial.

Antiretroviral therapy as HIV prevention: status and prospects

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

Antiretroviral treatment of primary HIV infection to reduce onward transmission

PURPOSE OF REVIEW

This review will discuss the role of antiretroviral therapy to treat primary HIV infection (PHI) as a strategy to prevent onward viral transmission.

RECENT FINDINGS

Novel technology has greatly enhanced the appreciation of the characteristics of recently transmitted HIV-1 variants. Recent primate data demonstrate marked enhanced infectiousness of viral variants isolated from acutely infected macaques compared with viruses isolated from animals in the chronic phase of disease. These data are supported by phylogenetic analyses of recently transmitted cases in humans, implying that individuals with PHI may contribute disproportionately to onward transmission at a population level.

SUMMARY

In the absence of randomized clinical trial data supporting individual benefit of antiretroviral therapy, targeting and treating individuals with PHI as a public health intervention strategy represent a paradigm shift from current treatment strategies based around proven individual benefit alone. However, there is increasing evidence that PHI contributes disproportionately to viral transmission at a population level and failure to incorporate the potential role PHI plays, particularly in focused epidemics, maybe a naïve omission of many of the current mathematical models evaluating the impact of universal test and treat on population-level HIV incidence.

HSV-2 serology can be predictive of HIV epidemic potential and hidden sexual risk behavior in the Middle East and North Africa

BACKGROUND

HIV prevalence is low in the Middle East and North Africa (MENA) region, though the risk or potential for further spread in the future is not well understood. Behavioral surveys are limited in this region and when available have serious limitations in assessing the risk of HIV acquisition. We demonstrate the potential use of herpes simplex virus-2 (HSV-2) seroprevalence as a marker for HIV risk within MENA.

METHODS

We designed a mathematical model to assess whether HSV-2 prevalence can be predictive of future HIV spread. We also conducted a systematic literature review of HSV-2 seroprevalence studies within MENA.

RESULTS

We found that HSV-2 prevalence data are rather limited in this region. Prevalence is typically low among the general population but high in established core groups prone to sexually transmitted infections such as men who have sex with men and female sex workers. Our model predicts that if HSV-2 prevalence is low and stable, then the risk of future HIV epidemics is low. However, expanding or high HSV-2 prevalence (greater than about 20%), implies a risk for a considerable HIV epidemic. Based on available HSV-2 prevalence data, it is not likely that the general population in MENA is experiencing or will experience such a considerable HIV epidemic. Nevertheless, the risk for concentrated HIV epidemics among several high-risk core groups is present.

CONCLUSIONS

HSV-2 prevalence surveys provide a useful mechanism for identifying and corroborating populations at risk for HIV within MENA. HSV-2 serology offers an effective tool for probing hidden sexual risk behaviors in a region where quality behavioral data are limited.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

A qualitative study of participant adherence in a randomized controlled trial of herpes suppressive therapy for HIV prevention in Tanzania

Poor participant adherence to treatment may contribute to lack of impact in some biomedical HIV prevention trials. This qualitative study explored adherence in a randomized controlled trial of herpes suppressive therapy to reduce HIV acquisition and infectivity among 1305 Tanzanian women. The trial found participants completed 72% of visits on treatment; 52-56% of women on treatment had > or = 90% adherence by pill count estimate; and between six and nine months 30/86 (35%) of urine samples from acyclovir recipients tested acyclovir negative, and 7/86 (8%) from placebo recipients tested acyclovir positive. Twenty in-depth interviews (IDIs) were conducted after 30 months with respondents randomly selected from "acyclovir negative" acyclovir recipients and "acyclovir positive" placebo recipients, or by preliminary pill count adherence categories ("under users," "good users," and "over users"). Almost all respondents reported appropriate adherence and positive trial attitudes, e.g., trusting staff, appreciating services, perceiving pills as beneficial. Fourteen understood placebo use, and six understood the trial purpose. Notably, 5/9 acyclovir recipients and 1/11 placebo recipients believed their pills had treated pre-existing sexually transmitted infections. Limited understanding did not negatively affect reported adherence. Reported adherence problems usually related to illness, travel, and/or family obligations (e.g., husband's disapproval). "Acyclovir positive" placebo recipients denied taking other participants' pills. The IDIs also did not resolve discrepant reports of pill loss or theft. Biomedical HIV interventions often have strong behavioral components that require close attention during intervention development, trial design, and process and impact evaluation. This study identified topics which warrant further consideration, including: information reinforcement and comprehension assessment throughout a trial for long-term participant understanding; involving partners in adherence promotion activities; strategizing with participants to maintain adherence during familial illnesses or other crises; and close monitoring, identification, and follow-up of (1) individuals with discrepant biological tests, and (2) other sources of the treatment in the trial area. Methodological research is also needed to improve adherence measures.

Population level impact of an imperfect prophylactic vaccine for herpes simplex virus-2

BACKGROUND

The continuation of developing Herpes simplex virus type-2 (HSV-2) prophylactic vaccines requires parallel mathematical modeling to quantify the effect on the population of these vaccines.

METHODS

Using mathematical modeling we derived 3 summary measures for the population effect of imperfect HSV-2 vaccines as a function of their efficacies in reducing susceptibility (VES), genital shedding (VEP), and infectivity during shedding (VEI). In addition, we studied the population level effect of vaccine intervention using representative vaccine efficacies.

RESULTS

A vaccine with limited efficacy of reducing shedding frequency (VEP = 10%) and infectivity (VEI = 0%) would need to reduce susceptibility by 75% (VES = 75%) to substantially reduce the sustainability of HSV-2 infection in a population. No reduction in susceptibility would be required to reach this target in a vaccine that decreased shedding by 75% (VES = 0%, VEP = 75%, VEI = 0%). Mass vaccination using a vaccine with imperfect efficacies (VES = 30%, VEP = 75%, and VEI = 0%) in Kisumu, Kenya, in 2010 would decrease prevalence and incidence in 2020 by 7% and 30%, respectively. For lower prevalence settings, vaccination is predicted to have a lower effect on prevalence.

CONCLUSION

A vaccine with substantially high efficacy of reducing HSV-2 shedding frequency would have a desirable effect at the population level. The vaccine's short-term impact in a high prevalence setting in Africa would be a substantial decrease in incidence, whereas its immediate impact on prevalence would be small and would increase slowly over time.

Setting the stage: current state of affairs and major challenges

The global human immunodeficiency virus (HIV) pandemic reached staggering proportions over the past 2 decades, particularly in areas of sub-Saharan Africa and other developing countries. Tremendous increases in donor resources over the past decade have allowed for a rapid scale-up of antiretroviral treatment and greater access to basic care and prevention programs in countries worst affected by HIV infection and AIDS. These programs have had a tremendous impact on the lives of millions of individuals and have also created optimism and hope where previously there was despair. Major challenges remain in combating the current HIV pandemic with regard to access to treatment; efficiency, quality, and sustainability of current programs; and the scale-up of evidence-based, effective prevention strategies. The global health community and political leaders will need to overcome these challenges if a long-term effective response to the HIV pandemic is to be achieved.

Contribution of sexually transmitted infections to the sexual transmission of HIV

PURPOSE OF REVIEW

We review recent evidence about the link between sexually transmitted infections (STI) and HIV transmission and consider implications for control programmes.

RECENT FINDINGS

New studies and meta-analyses confirm the association of HIV acquisition and transmission with recent STIs, although there is considerable heterogeneity between organisms and populations. Much of the recent evidence relates to herpes simplex virus type 2 (HSV-2), for which the population-attributable risk percentage (PAR%) for HSV-2 is between 25 and 35 in Africa. Mathematical models show how transmission attributable to STI varies with HIV epidemic phase, and HSV-2 becomes increasingly important as the epidemic matures. HSV-2 suppressive therapy reduces HIV concentrations in plasma and the genital tract in people coinfected with HSV-2, in part due to direct inhibition of HIV reverse transcriptase. Recent trials of HSV-2 suppressive therapy have not shown an impact on the risk of HIV acquisition, nor in controlling transmission from dually infected people to their serodiscordant heterosexual partners.

SUMMARY

Although there is a plausible link between STI and HIV risk, intervention studies continue to be disappointing. This fact does not disprove a causal link, but mechanisms of action and the design and implementation of interventions need to be better understood.

Can we reduce the spread of HIV infection by suppressing herpes simplex virus type 2 infection?

Overwhelming evidence from observational epidemiological studies indicates that herpes simplex virus type 2 (HSV-2) infection enhances the risk of acquiring HIV infection. Studies of genital shedding of HIV have suggested that HSV-2 infection also increases the onward transmission of HIV-1 by HIV/HSV-2 co-infected patients. Several randomized controlled trials were initiated to assess the impact of HSV-2 suppressive therapy on the acquisition of HIV infection by HSV-2 infected men and women, and on the onward transmission of HIV by HSV-2/HIV co-infected men and women. In the past 2 years the results of these trials have been published. HSV-2 suppressive therapy was not found to have any effect on HIV acquisition nor on onward transmission of HIV. However, suppressive therapy with acyclovir was found to slow down disease progression in HIV/HSV-2 co-infected patients. The effect was rather modest and cost-effectiveness studies are needed to assess whether HSV-2 suppressive therapy has a place in the management of HIV-1 infected patients, especially in low and middle income countries.

Interim modelling analysis to validate reported increases in condom use and assess HIV infections averted among female sex workers and clients in southern India following a targeted HIV prevention programme

Objectives

This study assesses whether the observed declines in HIV prevalence since the beginning of the ‘Avahan’ India HIV/AIDS prevention initiative are consistent with self-reported increases in condom use by female sex workers (FSWs) in two districts of southern India, and provides estimates of the fraction of new infections averted among FSWs and clients due to increases in condom use in commercial sex after 2004.

Methods

A deterministic compartmental model of HIV/sexually transmitted infection (STI) transmission incorporating heterogeneous sexual behaviour was developed, parameterised and fitted using data from two districts in Karnataka, India. Three hypotheses of condom use among FSWs were tested: (H₀), that condom use increased in line with reported FSW survey data prior to the Avahan initiative but remained constant afterwards; (H₁) that condom use increased following the Avahan initiative, in accordance with survey data; (H₂) that condom use increased according to estimates derived from condom distribution data. The proportion of fits to HIV/STI prevalence data was examined to determine which hypothesis was most consistent.

Results

For Mysore 0/36/82.7 fits were identified per million parameter sets explored under hypothesis H₀/H₁/H₂, respectively, while for Belgaum 9.7/8.3/0 fits were identified. The HIV epidemics in Belgaum and Mysore are both declining. In Mysore, increases in condom use during commercial sex between 2004 and 2009 may have averted 31.2% to 47.4% of new HIV infections in FSWs, while in Belgaum it may have averted 24.8% to 43.2%, if there was an increase in condom use.

Discussion

Increased condom use following the Avahan intervention is likely to have played a role in curbing the HIV epidemic in Mysore. In Belgaum, given the limitations in available data, this method cannot be used alone to decide if there has been an increase in condom use.

New concepts in understanding genital herpes

Herpes simplex virus (HSV)-2 is a lifelong infection that causes recurrent genital ulcers and, rarely, disseminated and visceral disease. HSV-1 infection is an increasingly important cause of genital ulcers. HSV infections are the most common cause of genital ulcers in adults, but acquisition and chronic infection are more commonly asymptomatic than symptomatic. Both the symptomatic and asymptomatic forms of HSV are of clinical consequence for several reasons. HSV-2 infection enhances HIV-1 acquisition and transmission. In addition, sexual and perinatal transmission can occur during asymptomatic viral shedding. Perinatal transmission is of particular concern because neonatal HSV infection results in severe morbidity to the newborn. Antiviral medicines are effective for limiting recurrence duration and decreasing transmission likelihood, although no available intervention completely prevents transmission. This fact highlights the importance of laboratory diagnostics for this lifelong infection, and the need for an HSV vaccine.

New insights on interactions between HIV-1 and HSV-2

Herpes simplex type 2 (HSV-2) infection is common and frequently asymptomatic. Concerns exist about the high prevalence of HSV-2, particularly in areas of high HIV prevalence, because of observations that HSV-2 is associated with an increased risk of HIV acquisition, transmission, and disease progression. Several randomized trials have tested or are testing whether HSV-2 treatment can limit the spread of HIV, with mixed results. Although treatment with acyclovir, 400 mg twice daily, does not reduce HIV incidence, suppressive acyclovir and valacyclovir reduce HIV levels in plasma and in the genital tract. Ongoing trials are evaluating whether HSV suppression will reduce HIV transmission and disease progression. Until a protective HSV-2 or HIV vaccine is available, effective interventions that reduce the effect of HSV-2 on HIV transmission are critically needed.

New biomedical strategies for HIV-1 prevention in women

Novel HIV-1 prevention strategies continue to be urgently needed. This article reviews the current state of biomedical prevention against HIV-1, focusing on recently completed and ongoing clinical trials of new prevention interventions, particularly those relevant to prevention of HIV-1 in women. Male circumcision, cervical barrier devices, suppressive therapy against herpes simplex virus type 2, treatment of vaginal infections and other vaginal health interventions, pre-exposure antiretroviral prophylaxis, and topical vaginal microbicides are discussed.

HIV infection in women: do sex and gender matter?

At least half of all HIV infections occur in women. Most women are of childbearing potential; therefore, issues encompassing reproduction and mother-to-child transmission are critical in the management of this population. The efficacy of antiretroviral therapy (ART) is similar in men and women, although rates of adverse events or toxicity may be higher in women, which, in turn, may be related to higher antiretroviral drug levels documented in pharmacokinetic studies. A substantial proportion of women may not derive the benefit of highly active ART because nonsuppressive regimens are commonly used, especially in resource-limited settings, to decrease mother-to-child transmission. The likely emergence of resistant virus can have long-term sequelae for the mother, child, and other exposed individuals. Additional studies are needed of sex/gender-related issues including antiretroviral toxicities, pharmacokinetic profiles of approved and novel agents, ART strategies during pregnancy to minimize HIV resistance, and determination of optimal antiretroviral regimens for women.

5th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention: summary of key research and implications for policy and practice - biomedical prevention

No major findings were reported at the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2009) on currently enrolled microbicides, pre-exposure prophylaxis (PrEP) or vaccine trials, although important findings in all three areas of biomedical prevention research are expected within the next few years.A study found that daily acyclovir did not reduce HIV transmission, but was a factor in modest reductions in viral load, which could confer some clinical benefit. Research demonstrating rapid viral replication in mucosal tissue and subsequent dissemination throughout the body suggested that research priorities should shift towards a mucosal vaccine. Findings reported in Track C indicated that, in addition to reducing vertical transmission, antiretroviral therapy (ART) also lowers the risk of prematurity, stillbirth and abortion.Challenging concerns about the potential "disinhibiting" effect of ART as prevention, a Kenyan study found that widespread ART encourages greater use of condoms and does not increase the rate of risky sex. Another Kenyan study found that pregnancy increases the risk of HIV transmission in a cohort of serodiscordant couples. Although three randomized trials have conclusively demonstrated that circumcision reduces HIV transmission among heterosexual men, research presented at IAS 2009 found no evidence of a preventive impact for women.

Etiology of genital ulcer disease. A prospective study of 278 cases seen in an STD clinic in Paris

OBJECTIVES

The goal of this study was to identify the causes and factors associated with genital ulcer disease (GUD) among patients attending a sexually transmitted disease (STD) clinic in Paris.

METHODS

This study was a prospective investigation of GUD cases. Data were collected from 1995 to 2005. In each case, a Dark Field Examination (DFE), Gram stain, inoculation onto Thayer Martin agar, Columbia agar and chocolate agar with 1% isovitalex and 20% fetal calf serum, PCR Chlamydia trachomatis (Amplicor Roche), culture for herpes simplex virus (HSV) on MRC 5 cells and PCR HSV (Argene Biosoft) were obtained from the ulceration. First Catch Urine (FCU) PCR for Chlamydia trachomatis and syphilis, HIV, HSV, and HBV serologies were also performed.

RESULTS

A total 278 cases of GUD were investigated, 244 (88%) in men and 34 (12%) in women. Primary syphilis accounted for 98 cases (35%), genital herpes for 74 (27%), chancroid for 8 (3%), other infections for 12 (5%). In 91 (32%) patients, no identifiable microorganism was documented. Primary syphilis was more prevalent in MSMs (P < 0.0001), while genital herpes and chancroid were significantly associated with heterosexuality (both P < 0.0001). A high level of HIV infection (27%) was found, particularly in patients with primary syphilis (33%). In the univariate analysis, no statistical difference was found between syphilis and herpes according to clinical presentation, pain being the only item slightly more frequent in herpes (P = 0.06). In the multivariable model syphilis was associated with being MSM (OR: 51.3 [95% CI: 14.7-178.7], P < 0.001) and with an ulceration diameter >10 mm (OR: 9.2 [95% CI: 2.9-30.7], P < 0.001). Genital herpes was associated with HIV infection in the subgroup of MSWs (OR: 24.4 [2.4-247.7], P = 0.007). We did not find significant differences in the clinical presentation of the ulcers according to HIV status.

CONCLUSION

The profound changes of the epidemiology of GUD during the decade, due to disappearance of chancroid and reemergence of infectious syphilis have led to a new distribution of pathogens, genital herpes, primary syphilis and GUD from unknown origin, accounting each for one third of cases. No clinical characteristic is predictive of the etiology, underlining the importance of performing a thorough microbiologic evaluation. Close association with HIV is still a major public health problem.

Long-term impact of acyclovir suppressive therapy on genital and plasma HIV RNA in Tanzanian women: a randomized controlled trial

BACKGROUND

Herpes simplex virus (HSV) suppressive therapy reduces genital and plasma human immunodeficiency virus type 1 (HIV-1) RNA over periods up to 3 months, but the long-term effect is unknown.

METHODS

A total of 484 HIV-1 and HSV type 2 seropositive Tanzanian women aged 16-35 years were enrolled in a randomized placebo-controlled trial of acyclovir administered at a dosage of 400 mg twice daily. Cervico-vaginal lavage and blood samples were collected at 6 months, 12 months, and 24 months for quantification of genital and plasma HIV-1 RNA and genital HSV DNA. Primary outcomes were detection and quantity of cervico-vaginal HIV-1 RNA at 6 months.

RESULTS

At 6 months, there was little difference between the acyclovir and placebo arms for cervico-vaginal HIV-1 RNA detection (88 [ 41 .3%] of 213 vs 84 [ 44 .0%] of 191; odds ratio [OR], 0.90; 95% confidence interval [CI], 0.60-1.33), HSV DNA detection (20 [ 9 .4%] of 213 vs 22 [ 11 .5%] of 191; OR, 0.80; 95% CI, 0.42-1.51), genital HIV or HSV loads, or plasma HIV-1 RNA load. Estimated median adherence was 91%. There was a suggestion of an impact on cervico-vaginal HIV-1 RNA detection among women with estimated adherence 90% (OR, 0.74; 95% CI, 0.50-1.09) when data from all 3 visits were included.

CONCLUSIONS

Acyclovir administered at a dosage of 400 mg twice daily is unlikely to be a useful long-term intervention to reduce HIV transmission. The lack of effect on HIV may be attributable to suboptimal adherence or treatment regimen.

Clinical and virologic efficacy of herpes simplex virus type 2 suppression by acyclovir in a multicontinent clinical trial

Acyclovir suppressive therapy (400 mg twice daily) reduces herpes simplex virus (HSV) type 2-associated genital ulcer disease and lesional HSV shedding. In an international trial of acyclovir for suppression of HSV type 2 to prevent human immunodeficiency virus (HIV) acquisition (HIV Prevention Trials Network 039), acyclovir had a smaller effect on the frequency of genital ulcer disease as well as a smaller effect on the frequency and quantity of lesional HSV DNA in African women and Peruvian men, compared with its effects in men in the United States. The observed regional variation in the clinical and virologic efficacy of acyclovir for HSV suppression warrants further evaluation of determinants of responses to acyclovir. (ClinicalTrials.gov identifier: NCT00076232.).

Clinical reactivations of herpes simplex virus type 2 infection and human immunodeficiency virus disease progression markers

Background

The natural history of HSV-2 infection and role of HSV-2 reactivations in HIV disease progression are unclear.

Methods

Clinical symptoms of active HSV-2 infection were used to classify 1,938 HIV/HSV-2 co-infected participants of the Women's Interagency HIV Study (WIHS) into groups of varying degree of HSV-2 clinical activity. Differences in plasma HIV RNA and CD4+ T cell counts between groups were explored longitudinally across three study visits and cross-sectionally at the last study visit.

Results

A dose dependent association between markers of HIV disease progression and degree of HSV-2 clinical activity was observed. In multivariate analyses after adjusting for baseline CD4+ T cell levels, active HSV-2 infection with frequent symptomatic reactivations was associated with 21% to 32% increase in the probability of detectable plasma HIV RNA (trend p = 0.004), an average of 0.27 to 0.29 log10 copies/ml higher plasma HIV RNA on a continuous scale (trend p<0.001) and 51 to 101 reduced CD4+ T cells/mm³ over time compared to asymptomatic HSV-2 infection (trend p<0.001).

Conclusions

HIV induced CD4+ T cell loss was associated with frequent symptomatic HSV-2 reactivations. However, effect of HSV-2 reactivations on HIV disease progression markers in this population was modest and appears to be dependent on the frequency and severity of reactivations. Further studies will be necessary to determine whether HSV-2 reactivations contribute to acceleration of HIV disease progression.

Microbicides and HIV prevention: lessons from the past, looking to the future

PURPOSE OF REVIEW

This review provides an update on developments in HIV microbicide research in the light of recent phase 3 efficacy studies and discusses how lessons learnt from early generation microbicide candidates can assist the development of future agents.

RECENT FINDINGS

Results of an interim analysis of a phase 3 trial suggested that cellulose sulfate increased the risk of HIV acquisition compared with placebo. Carraguard, SAVVY and Buffergel also failed to show any HIV protection in human efficacy trials. Recent research has focused on elucidating the reasons behind these failures as well as improving the assessment of safety and efficacy for the next generation of microbicide candidates. PRO 2000 0.5% gel is the only HIV microbicide candidate for which there are preliminary data suggesting efficacy in women. Antiretroviral agents and entry inhibitors may provide the key in the future to developing an effective HIV microbicide both for vaginal and rectal use.

SUMMARY

Development of a protective 'barrier' which can be controlled by the receptive partner independent of time of coitus remains a key goal in HIV prevention. A gel or ring-delivered combination of active anti-HIV agents may prove more efficacious than a single agent alone. Challenges in evaluating and manufacturing new candidates must be overcome before a well tolerated, effective, acceptable and affordable microbicide can be produced.

Targeting early infection to prevent HIV-1 mucosal transmission

Measures to prevent sexual mucosal transmission of human immunodeficiency virus (HIV)-1 are urgently needed to curb the growth of the acquired immunodeficiency syndrome (AIDS) pandemic and ultimately bring it to an end. Studies in animal models and acute HIV-1 infection reviewed here reveal potential viral vulnerabilities at the mucosal portal of entry in the earliest stages of infection that might be most effectively targeted by vaccines and microbicides, thereby preventing acquisition and averting systemic infection, CD4 T-cell depletion and pathologies that otherwise rapidly ensue.

Examining the promise of HIV elimination by 'test and treat' in hyperendemic settings

BACKGROUND

It has been suggested that a new strategy for HIV prevention, 'Universal Test and Treat', whereby everyone is tested for HIV once a year and treated immediately with antiretroviral therapy (ART) if they are infected, could 'eliminate' the epidemic and reduce ART costs in the long term.

METHODS

We investigated the impact of test-and-treat interventions under a variety of assumptions about the epidemic using a deterministic mathematical model.

RESULTS

Our model shows that such an intervention can substantially reduce HIV transmission, but that impact depends crucially on the epidemiological context; in some situations, less aggressive interventions achieve the same results, whereas in others, the proposed intervention reduces HIV by much less. It follows that testing every year and treating immediately is not necessarily the most cost-efficient strategy. We also show that a test-and-treat intervention that does not reach full implementation or coverage could, perversely, increase long-term ART costs.

CONCLUSION

Interventions that prevent new infections through ART scale-up may hold substantial promise. However, as plans move forward, careful consideration should be given to the nature of the epidemic and the potential for perverse outcomes.

Weighing the gold in the gold standard: challenges in HIV prevention research

OBJECTIVE(S)

Few HIV prevention interventions have been evaluated in randomized controlled trials (RCTs). We examined design, implementation, and contextual considerations that may limit detection of a positive or adverse effect in HIV prevention trials.

DESIGN

A systematic review of late phase RCTs for prevention of sexual transmission of HIV that randomly allocated intervention and comparison groups; evaluated interventions to prevent sexual transmission in nonpregnant populations; and reported HIV incidence as the primary or secondary outcome.

METHODS

PubMed/MEDLINE, other electronic databases, and electronic conference proceedings of recent HIV/AIDS-related conferences were searched to identify published or unpublished trials meeting the inclusion criteria. Descriptive, methodological, and contextual factors were abstracted from each trial.

RESULTS

The review included 37 HIV prevention RCTs reporting on 39 unique interventions. Only six RCTs, all evaluating biomedical interventions, demonstrated definitive effects on HIV incidence. Five of the six RCTs significantly reduced HIV infection: all three male circumcision trials, one trial of sexually transmitted infection treatment and care, and one vaccine trial. One microbicide trial of nonoxynol-9 gel produced adverse results. Lack of statistical power, poor adherence, and diluted versions of the intervention in comparison groups may have been important issues for the other trials that demonstrated 'flat' results.

CONCLUSION

Almost 90% of HIV prevention trials had 'flat' results, which may be attributable to trial design and/or implementation. The HIV prevention community must not only examine evidence from significant RCTs, but must also examine flat trials and address design and implementation issues that limit detection of an effect.

Population-based seroprevalence of HSV-2 and syphilis in Andhra Pradesh state of India

BACKGROUND

Understanding the prevalence and risk factors for common causes of ulcerative genital disease in the general population would inform current STI syndromic management and HIV testing strategies in high HIV prevalence regions of India.

METHODS

Persons 15-49 years old from 32 rural and 34 urban clusters were sampled using a stratified random method to represent adults in the high HIV prevalence Guntur district in Andhra Pradesh state. Interviews were conducted and dry blood spots were collected on 12,617 study participants. Testing for HSV-2 and syphilis was performed.

RESULTS

Adjusted HSV-2 and syphilis seroprevalence rates were 4.70% and 2.08% for men and 7.07% and 1.42% for women. For men, tattooing, >3 lifetime sex partners, tobacco use, and sex with men in the past 6 months were associated with HSV-2 or syphilis (ORs, 1.66-2.95, p < 0.05). Male circumcision was positively associated with HSV-2 infection (OR, 1.37, p = 0.028) though this could be due to residual confounding. In women, greater than one lifetime partner remained significantly associated with HSV-2 in multivariate analysis (OR, 2.61; 95% CI, 1.39-4.87). Among all behavioral risk factors and other covariates in women and men, HIV infection exhibited the strongest association with HSV-2 and syphilis (ORs, 8.2-14.2, p < 0.001). The proportion of individuals with HSV-2 who were HIV infected was less than the proportion with syphilis who were HIV infected (11.8% vs. 22.7%; p = 0.001).

CONCLUSIONS

Nearly one in four persons surveyed in this population-based study that were seroprevalent for syphilis, were also HIV infected. Common population risk factors for syphilis, HSV-2 and HIV and high rates of co-seroprevalence suggest that HIV testing, STI testing and service strategies for these would benefit from direct linkage in India.

A new class of dual-targeted antivirals: monophosphorylated acyclovir prodrug derivatives suppress both human immunodeficiency virus type 1 and herpes simplex virus type 2

BACKGROUND

Human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus type 2 (HSV-2) are responsible for 2 intersecting epidemics in which the disease caused by 1 virus facilitates the transmission of and pathogenesis by the other. Therefore, suppression of one virus infection will affect the other. Acyclovir, a common antiherpetic drug, was shown to directly suppress both viruses in coinfected tissues. However, both antiviral activities of acyclovir are dependent on phosphorylation by the nucleoside kinase activity of coinfecting human herpesviruses.

METHODS

We developed acyclovir ProTides, monophosphorylated acyclovir with the phosphate group masked by lipophilic groups to allow efficient cellular uptake, and investigated their antiviral potential in cell lines and in human tissues ex vivo.

RESULTS

Acyclovir ProTides suppressed both HIV-1 and HSV-2 at median effective concentrations in the submicromolar range in ex vivo lymphoid and cervicovaginal human tissues and at 3-12 micromol/L in CD4(+) T cells. Acyclovir ProTides retained activity against acyclovir-resistant HSV-2.

CONCLUSIONS

Acyclovir ProTides represent a new class of antivirals that suppress both HIV-1 and HSV-2 by directly and independently blocking the key replicative enzymes of both viruses. Further optimization of such compounds may lead to double-targeted antivirals that can prevent viral transmission and treat the 2 synergistic diseases caused by HIV-1 and HSV-2. To our knowledge, the acyclovir ProTides described here represent the first example of acyclic nucleoside monophosphate prodrugs being active against HIV-1.

One-day famciclovir vs. placebo in patient-initiated episodic treatment of recurrent genital herpes in immunocompetent Black patients

BACKGROUND

There are no known racial differences in genital herpes disease pathogenesis or response to therapy. Despite high herpes simplex virus (HSV) seroprevalence in Black persons, clinical trials investigating the treatment of recurrent genital herpes (RGH) have typically enrolled a small proportion of Black patients.

METHODS

This multicenter, double-blind, placebo-controlled study evaluated the efficacy and safety of patient-initiated, 1-day famciclovir 1000 mg twice-daily in immunocompetent Black adults (USA and South Africa) with RGH. Eligible patients were randomized (2:1) to famciclovir or placebo. The primary endpoint was time to healing of non-aborted genital herpes lesions (i.e., lesions that progressed beyond papule stage). Secondary endpoints included proportion of patients with aborted genital herpes lesions, time to resolution of associated symptoms, and safety.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov ; trial identifier NCT00477334.

RESULTS

A total of 299 patients with RGH (66% female, median age = 37 years) received either 1-day famciclovir 1000 mg twice-daily (n = 201) or placebo (n = 98). In the modified intent-to-treat population, the estimated median time to healing of non-aborted genital herpes lesions was 5.38 days for famciclovir and 4.79 days for placebo (median of treatment differences = 0.26 days; 95% CI [-0.40, 0.98]; p = 0.416). Consistent findings were reported in the completer and per-protocol populations. No significant differences were reported for all secondary analyses. Adverse events (AEs) were consistent with the established safety profile of famciclovir: 18 (6%) patients had drug-related AEs (16 [8%] famciclovir; 2 [2%] placebo), none of which were serious or led to discontinuation or dose adjustment/interruption. There are some limitations of this research: many study sites either lacked prior experience in conducting clinical studies in patients with HSV infection or enrolled small numbers of patients, which may have compromised efficacy outcomes. Also, HIV antibody testing was not mandated at enrollment.

CONCLUSION

This study showed similar efficacy and tolerability of 1-day treatment with famciclovir 1000 mg twice-daily compared to placebo in immunocompetent Black adults with RGH. Famciclovir has proven efficacy and safety in the overall RGH population. Further understanding of the efficacy of antiherpes therapy in Black patients with recurrent genital herpes may be warranted.

Double standards in research ethics, health-care safety, and scientific rigour allowed Africa's HIV/AIDS epidemic disasters

Medical professionals practising double standards in research ethics, health-care safety and scientific rigour have allowed HIV epidemics to develop into national disasters in more than a dozen countries in sub-Saharan Africa. Researchers have followed HIV-positive Africans who did not know they were infected to study HIV-related morbidity, mortality and transmission to unsuspecting spouses and children. Public health managers do not warn Africans about risks to contract HIV from unsafe health care, and no African government has investigated any unexplained and suspected nosocomial HIV infection by tracing and testing people who attended suspected clinics. Researchers have avoided finding and talking about nosocomial HIV infections in countries with generalized epidemics. Rejecting double standards in health-care safety and scientific rigour may be essential to solve and stop Africa's HIV epidemic. Allowing competitive international trade in generic drugs to treat AIDS could mitigate some of the harm done by these double standards.

Sensitivity of V75I HIV-1 reverse transcriptase mutant selected in vitro by acyclovir to anti-HIV drugs

Trials of acyclovir for herpes simplex virus 2 infection in herpes simplex virus 2/HIV-1 coinfected patients not on antiretroviral therapy demonstrated a decrease in herpes simplex virus 2 and HIV-1 replication. Recent studies indicated that acyclovir has direct anti-HIV-1 activity and can select for the HIV-1 V75I reverse transcriptase variant in vitro. We show that the V75I variant has decreased sensitivity to some nucleoside analogs but an increased sensitivity to zidovudine, results that may guide selection of highly active antiretroviral therapy regimens in patients harboring this variant.

Acyclovir: a new use for an old drug

PURPOSE OF REVIEW

Epidemiological studies have demonstrated that HIV-1 and herpes simplex virus-2 (HSV-2) are responsible for two epidemics and that, by overlapping in risk populations, they reinforce the spreading of both HIV-1 disease and genital herpes. Randomized controlled trials have investigated whether acyclovir (ACV), a synthetic drug designed to suppress herpes viruses, might provide an inexpensive and safe way to drastically reduce HIV-1 spreading around the world. The controversial results of these trials are reviewed below in light of the recent discovery of the direct suppression of HIV-1 by ACV.

RECENT FINDINGS

Recent studies have shown that although ACV therapy does not prevent HIV-1 transmission, it decreases plasma, genital, rectal, and seminal HIV-1 RNA levels. The decrease of HIV-1 load has been believed to be the result of an indirect mechanism and explained by reduction of HSV-2-mediated inflammation. The discovery of the direct inhibitory activity of ACV on HIV-1 reverse transcriptase brings new insights into the interpretation of these results. Also, it is important to understand why HSV-2-suppressive therapy with ACV did not reduce HIV-1 acquisition/transmission.

SUMMARY

The direct suppression of HIV-1 by ACV activated by coinfecting HSV-2 may in part explain the ACV-induced decrease of HIV load reported in several clinical trials. If this is the case, other herpes viruses capable of ACV activation may contribute to this effect. New basic studies and new targeted clinical trials are needed to understand whether ACV therapy can also be beneficial for HSV-2-negative patients. These studies will show whether ACV therapy should be included in HIV-1 treatment as well as whether ACV-based drugs specifically targeting HIV-1 can be developed.

Seroprevalence of herpes simplex virus type 1 and type 2 among the Indigenous population of Cape York, Far North Queensland, Australia

Background: The objective of this study was to obtain representative seroprevalence data for the Indigenous population of Far North Queensland by measuring the age- and sex-specific seroprevalence of the herpes simplex viruses (HSV-1 and HSV-2) in Cape York. Methods: A cross-sectional seroprevalence study was conducted using de-identified serum samples collected from Indigenous patients living in Cape York, aged 16 years or older, who sought medical care between August 2007 and May 2008. An age- and sex-stratified random sample of 270 sera was tested for the presence of antibodies to HSV-1 and HSV-2 using commercially available enzyme-linked immunosorbent assays. Indeterminate results were resolved with western blot. Results: The overall seroprevalence for the Indigenous population of Cape York was 97.8% for HSV-1 and 58.5% for HSV-2. There was a statistically significant difference in HSV-2 seroprevalence according to sex (P < 0.001). Females were more likely to be HSV-2 seropositive compared with males (72.1% and 43.8%, respectively). Conclusions: This is the first study to report on the seroprevalence of HSV-1 and HSV-2 among the Indigenous population of Cape York. This study has identified a population with an extremely high prevalence of HSV-1 and HSV-2 infection. The seroprevalence of HSV-2 in this population was found to be five times higher than that reported for the general adult Australian population. These results will be invaluable to the implementation of appropriate prevention and control strategies against HSV infection and are especially important considering the strong association between HSV-2 and the acquisition and transmission of HIV.

Increased risk of genital ulcer disease in women during the first month after initiating antiretroviral therapy

INTRODUCTION

Genital ulcer disease (GUD) is common in HIV-1-infected women, and a small number of studies have suggested increased GUD risk after antiretroviral therapy (ART) initiation. To better define this risk, we monitored 134 women at ART initiation and monthly thereafter.

METHODS

Women were evaluated monthly for genital ulcers. Syphilis serology was tested quarterly, and chancroid culture was performed on ulcers that were felt to be clinically consistent with a diagnosis of chancroid. A logistic model with generalized estimating equations was used to analyze predictors of GUD from baseline until 6 months after ART initiation.

RESULTS

During the study period, GUD occurred in 54 women (40.3%) at 85 visits (10.0%). GUD prevalence was 9.7% at baseline, increased to 16.7% at month 1 [adjusted odds ratio (aOR) 1.9 (1.0-3.6), P = 0.04], then decreased to 6.4% by month 6. History of GUD [aOR 3.8 (1.9-7.7), P < 0.001) and CD4 count <100 [aOR 1.8 (1.0-3.4), P = 0.06] were associated with increased risk of GUD after ART initiation.

DISCUSSION

Women experience increased risk of GUD in the first month after ART initiation, particularly if they have low CD4 counts or a history of GUD.

A macaque model to study vaginal HSV-2/immunodeficiency virus co-infection and the impact of HSV-2 on microbicide efficacy

Background

Herpes simplex virus type-2 (HSV-2) infection enhances the transmission and acquisition of human immunodeficiency virus (HIV). This occurs in symptomatic and asymptomatic stages of HSV-2 infection, suggesting that obvious herpetic lesions are not required to increase HIV spread. An animal model to investigate the underlying causes of the synergistic action of the two viruses and where preventative strategies can be tested under such complex physiological conditions is currently unavailable.

Methodology/Principal Findings

We set out to establish a rhesus macaque model in which HSV-2 infection increases the susceptibility to vaginal infection with a model immunodeficiency virus (simian-human immunodeficiency virus, SHIV-RT), and to more stringently test promising microbicides. HSV-2 exposure significantly increased the frequency of vaginal SHIV-RT infection (n = 6). Although cervical lesions were detected in only ∼10% of the animals, long term HSV-2 DNA shedding was detected (in 50% of animals followed for 2 years). Vaginal HSV-2 exposure elicited local cytokine/chemokine (n = 12) and systemic low-level HSV-2-specific adaptive responses in all animals (n = 8), involving CD4⁺ and CD8⁺ HSV-specific T cells (n = 5). Local cytokine/chemokine responses were lower in co-infected animals, while simian immunodeficiency virus (SIV)-specific adaptive responses were comparable in naïve and HSV-2-infected animals (n = 6). Despite the increased frequency of SHIV-RT infection, a new generation microbicide gel, comprised of Carraguard® and a non-nucleoside reverse transcriptase inhibitor MIV-150 (PC-817), blocked vaginal SHIV-RT infection in HSV-2-exposed animals (n = 8), just as in naïve animals.

Conclusions/Significance

We established a unique HSV-2 macaque model that will likely facilitate research to define how HSV-2 increases HIV transmission, and enable more rigorous evaluation of candidate anti-viral approaches in vivo.

A systematic review of the quality of trials evaluating biomedical HIV prevention interventions shows that many lack power

PURPOSE

Several randomized, controlled trials (RCTs) have tested strategies to prevent sexual acquisition of HIV infection, but their quality has been variable. We aimed to identify, describe, and evaluate the quality of RCTs studying biomedical interventions to prevent HIV acquisition by sexual transmission.

METHOD

We conducted a systematic review to identify all RCTs evaluating the efficacy of biomedical HIV prevention interventions. We assessed seven generic and content-specific quality components important in HIV prevention trials, factors influencing study power, co-interventions provided, and trial ethics.

RESULTS

We identified 26 eligible RCTs. The median number of quality components judged to be in adequate or unclear was 3 (range 1-4) in 1992-1998, 3 (range 1-4) in 1999-2003, and 0 (range0-2) in 2004-2008 (p < .001). Common problems that may have biased results included low retention (median 84%), poor adherence to interventions requiring on going use (median < or =78%), and lower HIV incidence than expected a priori (in 8 of 11 trials where evaluable).

CONCLUSION

Reporting of trials of biomedical HIV prevention interventions has improved over time. However, quality improvement is needed in several key areas that influence study power, including participant retention, adherence to interventions, and estimation of expected HIV incidence.

Concentrated and linked epidemics of both HSV-2 and HIV-1/HIV-2 infections in Senegal: public health impacts of the spread of HIV

The objective of this article is to report seroprevalences on HIV and herpes simplex virus 2 (HSV-2) in female sex workers (FSW) and in two sentinel populations of pregnant women living in Senegal. Serosurveys of HIV and HSV-2 were conducted in two unselected sentinel populations from Dakar, Senegal, and its provinces, including in 2003 only pregnant women and 2006 pregnant women and FSW. The population study involved 888 pregnant women and 604 FSW.

In pregnant women, HIV and HSV-2 seroprevalences were, respectively, 1.01% and 15.65%. There was no association between HSV-2 and HIV infection, whatever the age. In contrast, the seroprevalence of HIV infection in the group of FSW was high, reaching 22.9% in women over 30 years old. FSW above 20 years of age harboured much higher HSV-2 seroprevalences that those found in pregnant women of similar age groups. In FSW, strong associations between HSV-2 and age, and among HSV-2 and HIV-1 as well HIV-2, were evidenced. In conclusion, HIV epidemic remains concentrated in high-risk groups of the Senegalese population, such as the FSW population in which the seroprevalence of HSV-2 infection is very high. Intervention against STI including HSV-2 is urgently needed to prevent the spreading of HIV epidemic.

Effects of genital ulcer disease and herpes simplex virus type 2 on the efficacy of male circumcision for HIV prevention: Analyses from the Rakai trials

BACKGROUND

Randomized trials show that male circumcision (MC) reduces the incidence of HIV and herpes simplex virus type 2 (HSV-2) infections, and symptomatic genital ulcer disease (GUD). We assessed the role of GUD and HSV-2 in the protection against HIV afforded by MC.

METHODS AND FINDINGS

HIV-uninfected men were randomized to immediate (n = 2,756) or delayed MC (n = 2,775) in two randomized trials in Rakai, Uganda. GUD symptoms, HSV-2 status, and HIV acquisition were determined at enrollment and at 6, 12, and 24 mo of follow up. Ulcer etiology was assessed by PCR. We estimated the prevalence and prevalence risk ratios (PRRs) of GUD in circumcised versus uncircumcised men and assessed the effects of HSV-2 serostatus as a risk-modifying factor for GUD. We estimated the proportion of the effect of MC on HIV acquisition that was mediated by symptomatic GUD, and by HSV-2 infection. Circumcision significantly reduced symptomatic GUD in HSV-2-seronegative men (PRR = 0.51, 95% [confidence interval] CI 0.43-0.74), HSV-2-seropositive men (PRR = 0.66, 95% CI 0.51-0.69), and in HSV-2 seroconverters (PRR = 0.48, 95% CI 0.30-0.79). The proportion of acute ulcers due to HSV-2 detected by PCR was 48.0% in circumcised men and 39.3% in uncircumcised men (chi(2)p = 0.62). Circumcision reduced the risk of HIV acquisition in HSV-2 seronegative men (incidence rate ratio [IRR] = 0.34, 95% CI 0.15-0.81), and potentially in HSV-2 seroconverters (IRR = 0.56, 95% CI 0.19-1.57; not significant), but not in men with prevalent HSV-2 at enrollment (IRR = 0.89, 95% CI 0.49-1.60). The proportion of reduced HIV acquisition in circumcised men mediated by reductions in symptomatic GUD was 11.2% (95% CI 5.0-38.0), and the proportion mediated by reduced HSV-2 incidence was 8.6% (95% CI -1.2 to 77.1).

CONCLUSIONS

Circumcision reduced GUD irrespective of HSV-2 status, but this reduction played only a modest role in the protective effect of circumcision on HIV acquisition.