Transmission probabilities of HIV and HSV-2, effect of male circumcision and interaction: a longitudinal study in a township of South Africa

Ecole Nationale Supérieure Polytechnique de Yaoundé, Cameroon, South Africa.
AIDS (London, England) (Impact Factor: 5.55). 02/2009; 23(3):377-383. DOI: 10.1097/QAD.0b013e32831c5497
Source: PubMed


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

10 Reads
  • Source
    • "Randomized trials have shown that male circumcision decreased risk of HIV, HSV-2, and HPV infections in men [1]–[4]. One these trials also demonstrated decreased risk of trichomoniasis and bacterial vaginosis (BV) in the female sexual partners of circumcised men [5] as well as decreased symptomatic genital ulceration in both men and their female sexual partners [4], [6]. On the basis of the HIV findings, WHO/UNAIDS have recommended that circumcision be provided as part of a strategy for HIV prevention in men [7]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Circumcision is associated with significant reductions in HIV, HSV-2 and HPV infections among men and significant reductions in bacterial vaginosis among their female partners. We assessed the penile (coronal sulci) microbiota in 12 HIV-negative Ugandan men before and after circumcision. Microbiota were characterized using sequence-tagged 16S rRNA gene pyrosequencing targeting the V3-V4 hypervariable regions. Taxonomic classification was performed using the RDP Naïve Bayesian Classifier. Among the 42 unique bacterial families identified, Pseudomonadaceae and Oxalobactericeae were the most abundant irrespective of circumcision status. Circumcision was associated with a significant change in the overall microbiota (PerMANOVA p = 0.007) and with a significant decrease in putative anaerobic bacterial families (Wilcoxon Signed-Rank test p = 0.014). Specifically, two families-Clostridiales Family XI (p = 0.006) and Prevotellaceae (p = 0.006)-were uniquely abundant before circumcision. Within these families we identified a number of anaerobic genera previously associated with bacterial vaginosis including: Anaerococcus spp., Finegoldia spp., Peptoniphilus spp., and Prevotella spp. The anoxic microenvironment of the subpreputial space may support pro-inflammatory anaerobes that can activate Langerhans cells to present HIV to CD4 cells in draining lymph nodes. Thus, the reduction in putative anaerobic bacteria after circumcision may play a role in protection from HIV and other sexually transmitted diseases.
    Full-text · Article · Jan 2010 · PLoS ONE
  • [Show abstract] [Hide abstract]
    ABSTRACT: For generalised HIV/AIDS sub-Saharan African epidemics emphasis has been placed on the three established pillars of HIV prevention: condom promotion and distribution, Voluntary Counselling and Testing (VCT) and treatment of other sexually transmitted infections (STIs). Experiences in several countries support the positive results of Ugandan prevention politics called Abstinence, Be faithful, Condom (ABC), based on Primary Behaviour Change (PBC). Polemics tending to label this approach as “confessional based” have been recently intensified after Pope Benedict XVI recalled how the sole use of condoms cannot be considered the solution for HIV/AIDS in Africa. An honest and scientific approach to the dramatic reality of HIV/AIDS in Africa may yet require a reconsideration of the Western positions towards HIV prevention, accepting the potential challenge of a multifaceted strategy that uses all valid approaches, with particular regard to PBC: the elusive goal of vaccine, the simplistic trust in condoms, or acritical enthusiasm in drugs (either as therapy, postexposure or preventive treatment), mathematical modelling. All these are pieces of a complex puzzle. Synergy between treatment and prevention needs to be implemented in a realistic way, never forgetting that behaviour change is a process, not an event, involving human freedom and will. The need of a really participating community, with a prevention coming from below to the top and not from external over-imposing criteria, is also mandatory. Per fronteggiare l’epidemia da HIV nell’Africa sub sahariana ci si è a lungo basati sui tre cosiddetti “pilastri della prevenzione”: la promozione e la distribuzione di profilattici, la consulenza e il test volontario e il trattamento delle infezioni a trasmissione sessuale. Esperienze in diversi paesi supportano i risultati positivi della politica di prevenzione ugandese denominata “ABC” (Abstinence, Be-faithful, Condom), basata sulla modifica dei comportamenti sessuali (Primary Behavioural Change, PBC). Alcune polemiche, tendenti ad etichettare questo approccio come “confessionale”, si sono recentemente intensificate dopo che Papa Benedetto XVI ha ricordato come l’esclusivo uso del condom non può essere considerato la soluzione per il problema HIVAIDS in Africa. In questo lavoro vengono brevemente esaminati i principali indirizzi attuali di prevenzione, mostrando l’importanza dell’impatto del cambiamento comportamentale e del condom, la possibilità di ampliare la terapia antiretrovirale a scopo di prevenzione oltre che di trattamento ed infine le controversie delle opzioni della profilassi pre-esposizione e post esposizione. Un approccio onesto e scientifico alla drammatica realtà della epidemia da HIV in Africa richiede di rivedere la posizione occidentale verso la prevenzione, accettando la sfida di una strategia multiforme che utilizzi tutti i validi approcci, con particolare riguardo alla modifica dei comportamenti. L’attuale elusività di un efficace vaccino, la semplicistica fiducia nel preservativo o l’acritico entusiasmo nei farmaci, i modelli matematici: tutti questi sono solo singoli pezzi di un complesso puzzle. La sinergia tra trattamento e prevenzione deve essere attuata in modo realistico, non dimenticando mai che il cambiamento del comportamento è un processo dinamico, non un evento istantaneo, che coinvolge la libertà e la volontà umana. La necessità di una comunità veramente coinvolta, per una prevenzione che parte da un convincimento di base e non per la spinta di pressioni esterne, risulta di fondamentale importanza.
    No preview · Article · Aug 2009
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background and Objectives: A synergy between Human Immunode- feciency Virus (HIV) and Herpes Simplex Virus Type 2 (HSV-2) infec- tions has been reported in observational studies. Our objectives are a) to estimate the transmission probabilities (TPs) of these two infections, and b) to assess the effect of male circumcision and condom usage and HSV-2 on the HIV epidemic. Method: The method consists in observing individuals during follow- up visits. We then develop a Statistical Model. By using the Maximum Likelihood method we estimate the female-to-male TP parameters. The bootstrap procedure is used to estimate confidence intervals. Further, a compartmental model structured with gender is used to model the interactions between HIV and HSV-2 infections. Results: As an application of our method, we consider the association between HIV and HSV-2 using the male circumcision trial from the Or- ange Farm. We estimate the effect of male circumcision and condom usage in both HIV and HSV-2 TPs. Then we study the contribution of HSV-2 on HIV epidemic in a manhood circumcising community. Conclusion: According to our study, HSV-2 enhances the risk of HIV acquisition by males, and vice versa. These risks are shown to be reduced by male circumcision. Reducing the effect of HSV-2 on HIV transmission and acquisition together with promoting MC and condom usage are important to reduce HIV incidence.
    No preview · Article ·
Show more