Modélisation (Bio) Mathématique des interactions HSV-2/VIH à partir de données expérimentales

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF

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.: HSV-2, HIV and male circumcision

International audienceOBJECTIVES: 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

Association of the ANRS-12126 Male Circumcision Project with HIV Levels among Men in a South African Township: Evaluation of Effectiveness using Cross-sectional Surveys

<div><p>Background</p><p>Randomized controlled trials have shown that voluntary medical male circumcision (VMMC) reduces HIV infection by 50% to 60% in sub-Saharan African populations; however, little is known about the population-level effect of adult male circumcision (MC) as an HIV prevention method. We assessed the effectiveness of VMMC roll-out on the levels of HIV in the South African township of Orange Farm where the first randomized controlled trial (RCT) to test the effect of VMMC on HIV acquisition was conducted in 2002–2005.</p><p>Methods and Findings</p><p>The Bophelo Pele project is a community-based campaign against HIV, which includes the roll-out of free VMMC. A baseline cross-sectional biomedical survey was conducted in 2007–2008 among a random sample of 1,998 men aged 15 to 49 (survey response rate 80.7%). In 2010–2011, we conducted a follow-up random survey among 3,338 men aged 15 to 49 (survey response rate 79.6%) to evaluate the project. Participants were interviewed, blood samples were collected and tested for HIV and recent HIV infection (using the BED HIV incidence assay), and MC status was assessed through a clinical examination. Data were analyzed using multivariate and propensity statistical methods.</p><p>Owing to the VMMCs performed in the context of the RCT and the Bophelo Pele project, the prevalence rate of adult MC increased from 0.12 (95% CI 0.10–0.14) to 0.53 (95% CI 0.51–0.55). Without these VMMCs, the HIV prevalence rate in 2010–2011 would have been 19% (95% CI 12%–26%) higher (0.147 instead of 0.123).</p><p>When comparing circumcised and uncircumcised men, no association of MC status with sexual behavior was detected. Among circumcised and uncircumcised men, the proportion consistently using condoms with non-spousal partners in the past 12 months was 44.0% (95% CI 41.7%–46.5%) versus 45.4% (95% CI 42.2%–48.6%) with weighted prevalence rate ratio (wPRR) = 0.94 (95% CI 0.85–1.03). The proportion having two or more non-spousal partners was 50.4% (95% CI 47.9%–52.9%) versus 44.2% (95% CI 41.3%–46.9%) with wPRR = 1.03 (95% CI 0.95–1.10).</p><p>We found a reduction of BED-estimated HIV incidence rate ranging from 57% (95% CI 29%–76%) to 61% (95% CI 14%–83%) among circumcised men in comparison with uncircumcised men.</p><p>Conclusions</p><p>Findings suggest that the roll-out of VMMC in Orange Farm is associated with a significant reduction of HIV levels in the community. The main limitation of the study is that it was not randomized and cannot prove a causal association. The roll-out of VMMC among adults in sub-Saharan Africa should be an international priority and needs to be accelerated to effectively combat the spread of HIV.</p><p><i>Please see later in the article for the Editors' Summary</i></p></div

Characteristics of the sample surveyed in 2010–11 (follow-up survey) and association with male circumcision status.

<p>PRR obtained using log-binomial regression.</p>a<p>Adjusted on all the covariates in the table.</p>b<p>Self-reported, with non-spousal partners in the last 12 months.</p>*<p>Linear trend.</p

Variations among men of key outcomes between the baseline and the follow-up survey, and by circumcision status in the follow-up survey.

a<p>Standardized on the 2010 age-structure.</p>b<p>Proportion (%) consistently using condoms with non-spousal partners in the last 12 months.</p>c<p>The weights are the inverse of the propensity score, which was estimated from the basic covariates using logistic regression.</p>d<p>Proportion (%) having had two or more non-spousal partners in the last 12 months.</p><p>aPRR, prevalence rate ratio obtained using general linear models adjusted on basic covariates (age group, ethnic group, religion, having at least a child, occupation, age at first sexual intercourse, alcohol consumption, education level, and having ever been married); NA, not applicable.</p

HIV prevalence among circumcised and uncircumcised men in the follow-up survey.

<p>wHIV prevalence rate, weighted HIV prevalence rate; wPRR, weighted prevalence rate ratio using a propensity weighting score, which was estimated from the basic covariates (age group, ethnic group, religion, having at least a child, occupation, age at first sexual intercourse, alcohol consumption, education level, and ever having been married) using logistic regression.</p

Characteristics of the sample surveyed in 2007–2008 (baseline survey).

a<p>Self-reported, with non-spousal partners in the last 12 months.</p

HIV incidence rates and rate ratios obtained in 2010–2011 with the BED incidence assay for selected cut-off values, with and without corrections for misclassifications.

<p>The details of corrections-1 and -2 are provided in <a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001509#pmed.1001509.s004" target="_blank">Text S1</a>.</p>a<p>Standardized on the 2010 age-structure.</p>b<p>Adjusted on the following self reported sexual behavior covariates: lifetime number of sexual partners, consistent condom use with non-spousal partners in the last 12 months, and number of non-spousal partners in the last 12 months.</p><p>wIRR, weighted IRR using a propensity weighting score, which was estimated from the basic covariates (age group, ethnic group, religion, having at least a child, occupation, age at first sexual intercourse, alcohol consumption, education level, and ever having been married) using logistic regression.</p

Male circumcision prevalence rates by age group before and after the ANRS project in the community of Orange Farm (South Africa).

<p>The error bars represent the 95% confidence intervals.</p