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Find video protocols related to scientific articles indexed in Pubmed.
Changing inequalities in cervical cancer: modeling the impact of vaccine uptake, vaccine herd effects, and cervical cancer screening in the post-vaccination era.
Cancer Epidemiol. Biomarkers Prev.
PUBLISHED: 11-09-2014
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Background: Inequalities in cervical cancer may be increased following mass vaccination against the human papillomavirus (HPV) if girls with low vaccine uptake also have low future participation in cervical cancer screening. We evaluated how vaccine uptake distribution affects inequalities in squamous cell carcinoma (SCC) incidence between groups with different screening participation. Methods: We used an individual-based transmission dynamic model of HPV infection and disease (HPV-ADVISE). Females were stratified by routine screening frequency. We modeled the impact of vaccination on SCC incidence rate differences (absolute inequality) and incidence rate ratios (relative inequality) between women who have routine screening intervals of <5 years (frequently screened), ?5 years (under-screened), and who are never screened. We compared simulations with uniform vaccine uptake to scenarios with unequal vaccine uptake, where never and under-screened women have lower vaccine uptake than frequently screened women. Results: Absolute SCC inequalities between groups with different screening rates were predicted to decrease post-vaccination, even when women with the lowest screening participation had the lowest vaccine uptake. Herd effects helped reduce absolute inequalities when vaccine uptake was unequal. Conversely, relative SCC remained unchanged or increased post-vaccination. Results were robust to different overall vaccination coverages and sexual mixing scenarios. Conclusion: Though mass HPV vaccination is predicted to substantially decrease SCC incidence rates, never screened women will still have the highest disease burden post-vaccination. Impact: To reduce both absolute and relative SCC inequalities, public health initiatives will need to address inequalities in both vaccine uptake and in cervical cancer screening participation.
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The HIV care cascade and antiretroviral therapy in female sex workers: implications for HIV prevention.
Expert Rev Anti Infect Ther
PUBLISHED: 08-30-2014
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To achieve viral suppression and fully benefit from antiretroviral therapy (ART), it is important that individuals with HIV know that they are HIV infected, link to and remain in HIV care, start and remain on ART and adhere to treatment. In HIV epidemics where female sex workers (FSWs) are key drivers of HIV transmission, the extent to which FSWs use ART and engage in the HIV care cascade could have a considerable impact on HIV transmission from FSWs to the wider population. In this article we review the spectrum of FSW engagement in the HIV care cascade, look at the impact of the HIV care cascade and ART use among FSWs on population-level HIV transmission and discuss HIV prevention for FSWs in the context of ART and the HIV care cascade.
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Cost-effectiveness of HIV prevention for high-risk groups at scale: an economic evaluation of the Avahan programme in south India.
Lancet Glob Health
PUBLISHED: 08-27-2014
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Avahan is a large-scale, HIV preventive intervention, targeting high-risk populations in south India. We assessed the cost-effectiveness of Avahan to inform global and national funding institutions who are considering investing in worldwide HIV prevention in concentrated epidemics.
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Comparing the cost-effectiveness of two- and three-dose schedules of human papillomavirus vaccination: a transmission-dynamic modelling study.
Vaccine
PUBLISHED: 08-12-2014
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Recent evidence suggests that two doses of HPV vaccines may be as protective as three doses in the short-term. We estimated the incremental cost-effectiveness of two- and three-dose schedules of girls-only and girls & boys HPV vaccination programmes in Canada.
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Health benefits, costs, and cost-effectiveness of earlier eligibility for adult antiretroviral therapy and expanded treatment coverage: a combined analysis of 12 mathematical models.
Lancet Glob Health
PUBLISHED: 08-09-2014
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New WHO guidelines recommend initiation of antiretroviral therapy for HIV-positive adults with CD4 counts of 500 cells per ?L or less, a higher threshold than was previously recommended. Country decision makers have to decide whether to further expand eligibility for antiretroviral therapy accordingly. We aimed to assess the potential health benefits, costs, and cost-effectiveness of various eligibility criteria for adult antiretroviral therapy and expanded treatment coverage.
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An action agenda for HIV and sex workers.
Lancet
PUBLISHED: 07-26-2014
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The women, men, and transgender people who sell sex globally have disproportionate risks and burdens of HIV in countries of low, middle, and high income, and in concentrated and generalised epidemic contexts. The greatest HIV burdens continue to be in African female sex workers. Worldwide, sex workers still face reduced access to needed HIV prevention, treatment, and care services. Legal environments, policies, police practices, absence of funding for research and HIV programmes, human rights violations, and stigma and discrimination continue to challenge sex workers' abilities to protect themselves, their families, and their sexual partners from HIV. These realities must change to realise the benefits of advances in HIV prevention and treatment and to achieve global control of the HIV pandemic. Effective combination prevention and treatment approaches are feasible, can be tailored for cultural competence, can be cost-saving, and can help to address the unmet needs of sex workers and their communities in ways that uphold their human rights. To address HIV in sex workers will need sustained community engagement and empowerment, continued research, political will, structural and policy reform, and innovative programmes. But such actions can and must be achieved for sex worker communities everywhere.
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Global epidemiology of HIV among female sex workers: influence of structural determinants.
Lancet
PUBLISHED: 07-26-2014
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Female sex workers (FSWs) bear a disproportionately large burden of HIV infection worldwide. Despite decades of research and programme activity, the epidemiology of HIV and the role that structural determinants have in mitigating or potentiating HIV epidemics and access to care for FSWs is poorly understood. We reviewed available published data for HIV prevalence and incidence, condom use, and structural determinants among this group. Only 87 (43%) of 204 unique studies reviewed explicitly examined structural determinants of HIV. Most studies were from Asia, with few from areas with a heavy burden of HIV such as sub-Saharan Africa, Russia, and eastern Europe. To further explore the potential effect of structural determinants on the course of epidemics, we used a deterministic transmission model to simulate potential HIV infections averted through structural changes in regions with concentrated and generalised epidemics, and high HIV prevalence among FSWs. This modelling suggested that elimination of sexual violence alone could avert 17% of HIV infections in Kenya (95% uncertainty interval [UI] 1-31) and 20% in Canada (95% UI 3-39) through its immediate and sustained effect on non-condom use) among FSWs and their clients in the next decade. In Kenya, scaling up of access to antiretroviral therapy among FSWs and their clients to meet WHO eligibility of a CD4 cell count of less than 500 cells per ?L could avert 34% (95% UI 25-42) of infections and even modest coverage of sex worker-led outreach could avert 20% (95% UI 8-36) of infections in the next decade. Decriminalisation of sex work would have the greatest effect on the course of HIV epidemics across all settings, averting 33-46% of HIV infections in the next decade. Multipronged structural and community-led interventions are crucial to increase access to prevention and treatment and to promote human rights for FSWs worldwide.
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Two-dose strategies for human papillomavirus vaccination: how well do they need to protect?
Vaccine
PUBLISHED: 03-27-2014
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Two-dose human papillomavirus (HPV) vaccine schedules may provide short-term protection but their long-term population impact is unknown.
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Exploring the population-level impact of antiretroviral treatment: the influence of baseline intervention context.
AIDS
PUBLISHED: 01-29-2014
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To compare the potential population-level impact of expanding antiretroviral treatment (ART) in HIV epidemics concentrated among female sex workers (FSWs) and clients, with and without existing condom-based FSW interventions.
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Modelling in concentrated epidemics: informing epidemic trajectories and assessing prevention approaches.
Curr Opin HIV AIDS
PUBLISHED: 01-29-2014
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This review summarizes recent mathematical modelling studies conducted among key populations including MSM, people who inject drugs (PWID), and female sex workers (FSWs) in low prevalence settings used as a marker of concentrated epidemics.
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Community Mobilisation and Empowerment Interventions as Part of HIV Prevention for Female Sex Workers in Southern India: A Cost-Effectiveness Analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Most HIV prevention for female sex workers (FSWs) focuses on individual behaviour change involving peer educators, condom promotion and the provision of sexual health services. However, there is a growing recognition of the need to address broader societal, contextual and structural factors contributing to FSW risk behaviour. We assess the cost-effectiveness of adding community mobilisation (CM) and empowerment interventions (eg. community mobilisation, community involvement in programme management and services, violence reduction, and addressing legal policies and police practices), to core HIV prevention services delivered as part of Avahan in two districts (Bellary and Belgaum) of Karnataka state, Southern India.
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Optimal Allocation of Resources in Female Sex Worker Targeted HIV Prevention Interventions: Model Insights from Avahan in South India.
PLoS ONE
PUBLISHED: 01-01-2014
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The Avahan programme has provided HIV prevention activities, including condom promotion, to female sex workers (FSWs) in southern India since 2004. Evidence suggests Avahan averted 202,000 HIV infections over 4 years. For replicating this intervention elsewhere, it is essential to understand how the intervention's impact could have been optimised for different budget levels.
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Antiretroviral therapy uptake, attrition, adherence and outcomes among HIV-infected female sex workers: a systematic review and meta-analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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We aimed to characterize the antiretroviral therapy (ART) cascade among female sex workers (FSWs) globally.
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Positive impact of increases in condom use among female sex workers and clients in a medium HIV prevalence epidemic: modelling results from Project SIDA1/2/3 in Cotonou, Benin.
PLoS ONE
PUBLISHED: 01-01-2014
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A comprehensive, HIV prevention programme (Projet Sida1/2/3) was implemented among female sex workers (FSWs) in Cotonou, Benin, in 1993 following which condom use among FSWs increased threefold between 1993 and 2008 while FSW HIV prevalence declined from 53.3% to 30.4%.
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Validation of the modes of transmission model as a tool to prioritize HIV prevention targets: a comparative modelling analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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The static Modes of Transmission (MOT) model predicts the annual fraction of new HIV infections acquired across subgroups (MOT metric), and is used to focus HIV prevention. Using synthetic epidemics via a dynamical model, we assessed the validity of the MOT metric for identifying epidemic drivers (behaviours or subgroups that are sufficient and necessary for HIV to establish and persist), and the potential consequence of MOT-guided policies.
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The HIV Modes of Transmission model: a systematic review of its findings and adherence to guidelines.
J Int AIDS Soc
PUBLISHED: 01-01-2014
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The HIV Modes of Transmission (MOT) model estimates the annual fraction of new HIV infections (FNI) acquired by different risk groups. It was designed to guide country-specific HIV prevention policies. To determine if the MOT produced context-specific recommendations, we analyzed MOT results by region and epidemic type, and explored the factors (e.g. data used to estimate parameter inputs, adherence to guidelines) influencing the differences.
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Distinguishing sources of HIV transmission from the distribution of newly acquired HIV infections: why is it important for HIV prevention planning?
Sex Transm Infect
PUBLISHED: 09-20-2013
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The term source of HIV infections has been referred to as the source of HIV transmission. It has also been interpreted as the distribution of newly acquired HIV infections across subgroups. We illustrate the importance of distinguishing the two interpretations for HIV prevention planning.
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Female sex worker client behaviors lead to condom breakage: a prospective telephone-based survey in Bangalore, South India.
AIDS Behav
PUBLISHED: 08-07-2013
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We examined condom breakage rates and predictors of breakage in a prospective telephone-based study of female sex workers (FSWs) in Bangalore, India. We obtained data on 3,257 condom-use sex acts, and breakage occurred in 2.1 % of these. Situational factors, especially those associated with male clients behaviors, were the most important predictors of breakage, including sexual inexperience, roughness and violence. Breakage was also associated with having vaginal and anal sex at the same encounter and with poor-fitting condoms. Despite lower than expected breakage rates, the high client volume of FSWs means that there are many unprotected sex acts caused by breakage. Discussions should be held around new education messages, and how programs can respond quickly when sex workers encounter clients who are inebriated, violent or unusually sexually charged. More work is urgently needed with police, and on FSW empowerment, the use of help lines, and counseling for the most vulnerable women.
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Potential cost-effectiveness of the nonavalent human papillomavirus (HPV) vaccine.
Int. J. Cancer
PUBLISHED: 07-26-2013
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Randomized clinical trials are currently examining the efficacy of a nonavalent human papillomavirus (HPV) vaccine, including HPV-types 6/11/16/18/31/33/45/52/58. Evidence on the cost-effectiveness of the nonavalent is required for timely policy-decisions. We compared the potential cost-effectiveness of the nonavalent and quadrivalent HPV vaccines. We used a multi-type individual-based transmission-dynamic model of HPV infection and diseases, 70-year time-horizon, 3% discount rate and healthcare payer perspective. We calibrated the model to Canadian sexual behavior and epidemiologic data, and estimated Quality-Adjusted Life-Years (QALYs) lost and costs ($CAN 2010) from the literature. Under base-case assumptions (vaccinating 10-year-old girls, 80% coverage, 95$/dose, vaccine-type efficacy = 95%, cross-protection for the quadrivalent vaccine, duration of vaccine-type protection (cross-protection) = 20 (10) years), using the quadrivalent and nonavalent vaccines is estimated to cost $15,528 [12,056; 19,140] and $12,203 [9,331; 17,292] per QALY-gained, respectively. At equal price, the nonavalent vaccine is more cost-effective than the quadrivalent vaccine, even when assuming both shorter duration of protection (nonavalent = 20 years vs. quadrivalent = lifelong) and lower vaccine-type efficacy (nonavalent = 85% vs. quadrivalent = 95%). However, the additional cost per dose of the nonavalent vaccine should not exceed $11 to remain more cost-effective than the quadrivalent vaccine, and $24 to represent a cost-effective alternative to the quadrivalent vaccine (using a $40,000/QALY-gained threshold). The nonavalent vaccine can be a cost-effective alternative to the quadrivalent vaccine, even in scenarios where nonavalent vaccine efficacy is 85%. However, because most cervical cancers are caused by HPV-16/18, it is unlikely that the nonavalent would be used if its efficacy against these types is lower than current HPV vaccines.
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Heterosexual HIV-1 infectiousness and antiretroviral use: systematic review of prospective studies of discordant couples.
Epidemiology
PUBLISHED: 06-01-2013
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Recent studies have estimated the reduction in HIV-1 infectiousness with antiretroviral therapy (ART), but high-quality studies such as randomized controlled trials, accompanied by rigorous adherence counseling, are likely to overestimate the effectiveness of treatment-as-prevention in real-life settings.
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Assessment of HIV-related risky behaviour: a comparative study of face-to-face interviews and polling booth surveys in the general population of Cotonou, Benin.
Sex Transm Infect
PUBLISHED: 05-30-2013
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During the 2008 HIV prevalence survey carried out in the general population of Cotonou, Benin, face-to-face interviews (FTFI) were used to assess risky behaviours for HIV and other sexually transmitted infections (STI). We compared sexual behaviours reported in FTFI with those reported in polling booth surveys (PBS) carried out in parallel in an independent random sample of the same population.
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Sociodemographic inequalities in sexual activity and cervical cancer screening: implications for the success of human papillomavirus vaccination.
Cancer Epidemiol. Biomarkers Prev.
PUBLISHED: 04-04-2013
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Papanicolaou smear screening has significantly reduced cervical cancer morbidity and mortality. However, inequalities still persist across different socioeconomic status (SES) groups. These inequalities have been associated with differential participation in screening. However, even with equal participation to screening, some women may still have greater risk of cervical cancer because of sexual behavior. We aim to identify the sociodemographic characteristics of women who reported greater sexual activity and/or screening underuse.
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Comparative cost-effectiveness of the quadrivalent and bivalent human papillomavirus vaccines: a transmission-dynamic modeling study.
Vaccine
PUBLISHED: 03-18-2013
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The quadrivalent and bivalent human papillomavirus (HPV) vaccines are now licensed in several countries. We compared the cost-effectiveness of the HPV vaccines to provide evidence for policy decisions.
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Positive impact of a large-scale HIV prevention programme among female sex workers and clients in South India.
AIDS
PUBLISHED: 03-07-2013
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Estimate the potential impact of Avahan, the India AIDS Initiative, among female sex workers (FSWs) and their clients in five districts of Karnataka state, south India.
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Violence and HIV risk among female sex workers in Southern India.
Sex Transm Dis
PUBLISHED: 02-27-2013
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This study characterized the type and frequency of violence against female sex workers (FSWs) perpetrated by their clients and their main intimate or other nonpaying partner (NPP) and examined the relationship between violence and inconsistent condom use (ICU, G100%). The factors associated with client violence were also assessed.
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Beating the placebo in HIV prevention efficacy trials: the role of the minimal efficacy bound.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 02-27-2013
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To produce an effect on the HIV epidemic, preventive interventions need to achieve a minimum level of efficacy to offset potential indirect effects such as an increase in risky behavior. The current generation of HIV prevention trials on oral preexposure prophylaxis and on vaginal microbicides were designed using different set points for minimum individual-level efficacy (MIE). Some trials were designed not only to show superiority over placebo but also to rule out lower efficacies. The MIE has a substantial impact on the size and cost of a trial. Ideally, the MIE should be chosen to reduce uncertainty in the estimation of population-level effects. In this article, we investigate the effect of MIE on estimates of population-level impact to better inform trial design.
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Decline in the prevalence of HIV and sexually transmitted infections among female sex workers in Benin over 15 years of targeted interventions.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 01-23-2013
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An HIV-preventive intervention targeting the sex work milieu and involving fully integrated components of structural interventions, communication for behavioral change and care for sexually transmitted infections (STIs), was implemented in Benin by a Canadian project from 1992 to 2006. It first covered Cotonou before being extended to other main cities from 2000. At the project end, the Beninese authorities took over the intervention, but structural interventions were interrupted and other intervention components were implemented separately. We estimated time trends in HIV/STI prevalence among female sex workers (FSWs) from 1993 to 2008 and assessed the impact of the change in intervention model on trends.
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The impact of differential uptake of HPV vaccine by sexual risks on health inequalities: a model-based analysis.
Vaccine
PUBLISHED: 01-15-2013
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Differences in sexual behaviour are partly responsible for significant inequalities in human papillomavirus (HPV)-related diseases between sub-populations. Our aim was to illustrate how differential HPV vaccine uptake by sexual behaviour can impact population-level vaccination effectiveness and inequalities in HPV prevalence.
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Analytic Review of Modeling Studies of ARV Based PrEP Interventions Reveals Strong Influence of Drug-Resistance Assumptions on the Population-Level Effectiveness.
PLoS ONE
PUBLISHED: 01-01-2013
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Four clinical trials have shown that oral and topical pre-exposure prophylaxis (PrEP) based on tenofovir may be effective in preventing HIV transmission. The expected reduction in HIV transmission and the projected prevalence of drug resistance due to PrEP use vary significantly across modeling studies as a result of the broad spectrum of assumptions employed. Our goal is to quantify the influence of drug resistance assumptions on the predicted population-level impact of PrEP.
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Population-level benefits from providing effective HIV prevention means to pregnant women in high prevalence settings.
PLoS ONE
PUBLISHED: 01-01-2013
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HIV prevalence among pregnant women in Southern Africa is extremely high. Epidemiological studies suggest that pregnancy increases the risk of HIV sexual acquisition and that HIV infections acquired during pregnancy carry higher risk of mother-to-child transmission (MTCT). We analyze the potential benefits from extending the availability of effective microbicide to pregnant women (in addition to non-pregnant women) in a wide-scale intervention.
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Vaccinating Girls and Boys with Different Human Papillomavirus Vaccines: Can It Optimise Population-Level Effectiveness?
PLoS ONE
PUBLISHED: 01-01-2013
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Decision-makers may consider vaccinating girls and boys with different HPV vaccines to benefit from their respective strengths; the quadrivalent (HPV4) prevents anogenital warts (AGW) whilst the bivalent (HPV2) may confer greater cross-protection. We compared, to a girls-only vaccination program with HPV4, the impact of vaccinating: 1) both genders with HPV4, and 2) boys with HPV4 and girls with HPV2.
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Condom use within non-commercial partnerships of female sex workers in southern India.
BMC Public Health
PUBLISHED: 12-29-2011
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Although female sex workers (FSWs) report high levels of condom use with commercial sex clients, particularly after targeted HIV preventive interventions have been implemented, condom use is often low with non-commercial partners. There is limited understanding regarding the factors that influence condom use with FSWs non-commercial partners, and of how programs can be designed to increase condom use with these partners. The main objectives of this study were therefore to describe FSWs self-reported non-commercial partners, along with interpersonal factors characterizing their non-commercial partnerships, and to examine the factors associated with consistent condom use (CCU) within non-commercial partnerships.
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A dose-response relationship between exposure to a large-scale HIV preventive intervention and consistent condom use with different sexual partners of female sex workers in southern India.
BMC Public Health
PUBLISHED: 12-29-2011
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The Avahan Initiative, a large-scale HIV preventive intervention targeted to high-risk populations including female sex workers (FSWs), was initiated in 2003 in six high-prevalence states in India, including Karnataka. This study assessed if intervention exposure was associated with condom use with FSWs sexual partners, including a dose-response relationship.
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The future role of rectal and vaginal microbicides to prevent HIV infection in heterosexual populations: implications for product development and prevention.
Sex Transm Infect
PUBLISHED: 11-24-2011
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To compare the potential impact of rectal (RMB), vaginal (VMB) and bi-compartment (RVMB) (applied vaginally and protective during vaginal and anal intercourse) microbicides to prevent HIV in various heterosexual populations. To understand when a RMB is as useful than a VMB for women practicing anal intercourse (AI).
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Incremental impact of adding boys to current human papillomavirus vaccination programs: role of herd immunity.
J. Infect. Dis.
PUBLISHED: 07-12-2011
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Our aim was to examine the potential incremental impact of vaccinating boys against human papillomavirus (HPV) on vaccine-type infection in females and males, using an individual-based HPV transmission-dynamic model. Under base assumptions (vaccine efficacy = 99%, duration of protection = 20 years, coverage = 70%), vaccinating 12-year-old boys, in addition to girls, resulted in an incremental reduction in HPV-16/18 (HPV-6/11) incidence over 70 years of 16% (3%) in females and 23% (4%) in males. The benefit of vaccinating boys decreased with improved vaccination coverage in girls. Given the important predicted herd immunity impact of vaccinating girls under moderate to high vaccine coverage, the potential incremental gains of vaccinating boys are limited.
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The forgotten half of the equation: randomized controlled trial of a male invitation to attend couple voluntary counselling and testing.
AIDS
PUBLISHED: 05-26-2011
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Increased male participation in antenatal care and uptake of couple voluntary counselling and testing (VCT) for HIV could reduce horizontal and vertical HIV transmission in sub-Saharan Africa.
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What do mathematical models tell us about the emergence and spread of drug-resistant HIV?
Curr Opin HIV AIDS
PUBLISHED: 04-21-2011
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To discuss recent HIV epidemic models examining the transmission of antiretroviral (ARV) drug resistance.
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Differential gene expression profiling in the mouse brain during motor skill learning: focus on the striatum structure.
Behav. Brain Res.
PUBLISHED: 02-18-2011
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Much research has implicated the striatum in motor learning, but the underlying mechanism is still under extensive investigation. In this study, genome-wide analysis of gene expression was conducted in mice that have learned a complex motor task. It is well recognized that successful learning requires repetitive training and is learned slowly over several training sessions. We therefore used mice that have fully learned the accelerating rotarod task that discriminates the faster and slower phases of motor learning. As important modulators of movement behavior, the striatum was the target of this analysis along with the cerebellum and anterior cortex. To identify potential genes implicated in long memorization process, we compared the lists of genes modulated in the striatum to those modulated in the cerebellum and cortex. As a second approach, we also determined which gene ontology categories were enriched in modulated striatal genes and identified genes with the highest numbers of annotation throughout categories. Although only some of these changes were further confirmed by RT-PCR, these two complementary analyses allowed the identification of highly relevant genes like calcium/calmodulin-dependent protein kinase 2, protein kinase C zeta and N-methyl-D-aspartate receptors. Notably, these genes are all associated with synaptic plasticity, suggesting that stabilized neuronal connections in the striatum are the foundation of durable motor memory. Our study provides the first report of a whole genome analysis of gene expression in mice that have memorized a new complex motor task, and expands our knowledge on striatal gene expression changes associated with motor skill learning.
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Modeling the gender-specific impact of vaginal microbicides on HIV transmission.
J. Theor. Biol.
PUBLISHED: 01-06-2011
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Vaginal microbicides (VMB) are currently among the few women-initiated biomedical interventions for preventing heterosexual transmission of HIV. In this paper we use a deterministic model of HIV transmission to assess the public-health benefits of a VMB intervention and evaluate its gender-specific impact over short (initial) and extended periods of time. We define two distinct quantitative benefit ratios (QBRs) based on infections prevented in men and women to create and study regions of male advantage in different parameter spaces. Our analysis exposes complicated temporal correlations between the QBRs and series of pre-intervention (e.g., HIV acquisition risks per act) and intervention parameters (e.g., VMB efficacy mechanisms, rates of resistance development and reversion) and indicates that different QBRs may often disagree on the gender distribution of the benefits from a VMB intervention. We also outline the strong influence of some modeling assumptions on the reported results and conclude that the assessment of VMB and other biomedical interventions must be based on more comprehensive analyses than calculations of infections prevented over a fixed period of time.
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Factors associated with numbers of client partners of female sex workers across five districts in South India.
Sex Transm Dis
PUBLISHED: 10-27-2010
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This study investigated the structural-environmental and individual-level social factors associated with the numbers of commercial sex clients of female sex workers (FSWs) per month (CPM).
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The ABC of terms used in mathematical models of infectious diseases.
J Epidemiol Community Health
PUBLISHED: 10-21-2010
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Mathematical models that incorporate a dynamic risk of infection figure prominently in the study of infectious diseases epidemiology as a tool to inform public health policy. In recent years, their use has expanded to address methodological questions, inform and validate study design and evaluate interventions. This glossary briefly highlights the applications of transmission dynamics modelling, explains different modelling methodologies and defines commonly encountered terms to provide an introductory and conceptual understanding of the vocabulary and frameworks used in the literature.
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Different population-level vaccination effectiveness for HPV types 16, 18, 6 and 11.
Sex Transm Infect
PUBLISHED: 10-05-2010
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Given that the human papillomavirus (HPV) vaccine types have different durations of infectiousness and infectivity, the population-level vaccine effectiveness of these types may differ even if vaccine efficacy is identical.
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To what extent is the HIV epidemic in southern India driven by commercial sex? A modelling analysis.
AIDS
PUBLISHED: 09-21-2010
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In south India, general population HIV prevalence estimates range from 0.5 to 3%. To focus HIV prevention efforts, it is important to understand whether HIV transmission is driven by commercial sex.
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A systematic review and meta-analysis of quantitative interviewing tools to investigate self-reported HIV and STI associated behaviours in low- and middle-income countries.
Int J Epidemiol
PUBLISHED: 07-14-2010
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Studies identifying risks and evaluating interventions for human immunodeficiency virus (HIV) and other sexually transmitted infections often rely on self-reported measures of sensitive behaviours. Such self-reports can be subject to social desirability bias. Concerns over the accuracy of these measures have prompted efforts to improve the level of privacy and anonymity of the interview setting. This study aims to determine whether such novel tools minimize misreporting of sensitive information.
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HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention.
Int J Epidemiol
PUBLISHED: 04-20-2010
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The human immunodeficiency virus (HIV) infectiousness of anal intercourse (AI) has not been systematically reviewed, despite its role driving HIV epidemics among men who have sex with men (MSM) and its potential contribution to heterosexual spread. We assessed the per-act and per-partner HIV transmission risk from AI exposure for heterosexuals and MSM and its implications for HIV prevention.
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Understanding differences in predictions of HPV vaccine effectiveness: A comparative model-based analysis.
Vaccine
PUBLISHED: 03-19-2010
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Mathematical models of HPV vaccine effectiveness and cost-effectiveness have produced conflicting results. The aim of this study was to use mathematical models to compare and isolate the impact of the assumptions most commonly made when modeling the effectiveness of HPV vaccines. Our results clearly show that differences in how we model natural immunity, herd immunity, partnership duration, HPV types, and waning of vaccine protection lead to important differences in the predicted effectiveness of HPV vaccines. These results are important and useful to assist modelers/health economists in choosing the appropriate level of complexity to include in their models, provide epidemiologists with insight on key data necessary to increase the robustness of model predictions, and help decision makers better understand the reasons underlying conflicting results from HPV models.
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A novel approach to investigate tissue-specific trinucleotide repeat instability.
BMC Syst Biol
PUBLISHED: 03-19-2010
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In Huntingtons disease (HD), an expanded CAG repeat produces characteristic striatal neurodegeneration. Interestingly, the HD CAG repeat, whose length determines age at onset, undergoes tissue-specific somatic instability, predominant in the striatum, suggesting that tissue-specific CAG length changes could modify the disease process. Therefore, understanding the mechanisms underlying the tissue specificity of somatic instability may provide novel routes to therapies. However progress in this area has been hampered by the lack of sensitive high-throughput instability quantification methods and global approaches to identify the underlying factors.
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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.
Sex Transm Infect
PUBLISHED: 02-20-2010
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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.
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Syphilis screening among female sex workers in Bangalore, India: comparison of point-of-care testing and traditional serological approaches.
Sex Transm Infect
PUBLISHED: 12-03-2009
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We undertook a prospective evaluation of the Qualpro Syphicheck-WB rapid syphilis test to measure its diagnostic performance and utility as a point-of-care (POC) screening test among female sex workers (FSWs) in Bangalore, India.
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Economic evaluation of human papillomavirus vaccination in developed countries.
Public Health Genomics
PUBLISHED: 08-11-2009
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With promising efficacy results from randomized control trials of human papillomavirus (HPV) vaccines and the availability of new screening paradigms, policymakers are being asked to make recommendations and decisions regarding the optimal strategies to reduce HPV infection and disease. Such decisions are increasingly being made with significant input from mathematical and economic models. The demand for modeling has resulted in the publication of numerous mathematical models looking at the cost-effectiveness of HPV vaccination.
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Efficacy dilution in randomized placebo-controlled vaginal microbicide trials.
Emerg Themes Epidemiol
PUBLISHED: 05-06-2009
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To date different vaginal gel microbicides have been evaluated in phase 2b/3 trials, but none have demonstrated effectiveness for preventing HIV infection. Failure to demonstrate effectiveness however does not necessarily indicate that a product is truly inefficacious, as several sources of efficacy dilution may compromise our ability to identify products that may have been truly efficacious.
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Heterosexual risk of HIV-1 infection per sexual act: systematic review and meta-analysis of observational studies.
Lancet Infect Dis
PUBLISHED: 01-31-2009
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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.
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Heterosexual anal intercourse: a neglected risk factor for HIV?
Am. J. Reprod. Immunol.
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Heterosexual anal intercourse confers a much greater risk of HIV transmission than vaginal intercourse, yet its contribution to heterosexual HIV epidemics has been under-researched. In this article we review the current state of knowledge of heterosexual anal intercourse practice worldwide and identify the information required to assess its role in HIV transmission within heterosexual populations, including input measures required to inform mathematical models. We then discuss the evidence relating anal intercourse and HIV with sexual violence.
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Informal confidential voting interviewing in a sexual risk assessment of men who have sex with men (MSM) and transgenders (hijra) in Bangalore, India.
Sex Transm Infect
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The accuracy of self-reporting sensitive sexual risk behaviours is highly susceptible to misreporting. Informal confidential voting interviews (ICVIs) may minimise social desirability bias by increasing the privacy of the interview setting. The objective was to investigate determinants of risky behaviour among men who have sex with men (MSM) and hijra (transgenders) reported through two interviewing tools: ICVIs and face-to-face interviews (FTFIs).
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Impact of high-risk sex and focused interventions in heterosexual HIV epidemics: a systematic review of mathematical models.
PLoS ONE
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The core-group theory of sexually transmitted infections suggests that targeting prevention to high-risk groups (HRG) could be very effective. We aimed to quantify the contribution of heterosexual HRGs and the potential impact of focused interventions to HIV transmission in the wider community.
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Population-level impact of the bivalent, quadrivalent, and nonavalent human papillomavirus vaccines: a model-based analysis.
J. Natl. Cancer Inst.
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Bivalent and quadrivalent human papillomavirus (HPV) vaccines are now licensed in several countries. Furthermore, clinical trials examining the efficacy of a nonavalent vaccine are underway. We aimed to compare the potential population-level effectiveness of the bivalent, quadrivalent, and candidate nonavalent HPV vaccines.
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Decline in HIV prevalence among young men in the general population of Cotonou, Benin, 1998-2008.
PLoS ONE
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To assess changes in the prevalence of HIV and other sexually transmitted infections, as well as in different proximal and distal factors related to HIV infection, in the general population of Cotonou between 1998 and 2008, while an intensive preventive intervention targeting the sex work milieu was ongoing.
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Cross-protective efficacy of two human papillomavirus vaccines: a systematic review and meta-analysis.
Lancet Infect Dis
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The extent of cross-protection is a key element in the choice of human papillomavirus (HPV) vaccine to use in vaccination programmes. We compared the cross-protective efficacy of the bivalent vaccine (HPV 16 and 18; Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and quadrivalent vaccine (HPV 6, 11, 16, and 18; Gardasil, Merck, Whitehouse Station, NJ, USA) against non-vaccine type HPVs.
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HIV treatment as prevention: considerations in the design, conduct, and analysis of cluster randomized controlled trials of combination HIV prevention.
PLoS Med.
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The rigorous evaluation of the impact of combination HIV prevention packages at the population level will be critical for the future of HIV prevention. In this review, we discuss important considerations for the design and interpretation of cluster randomized controlled trials (C-RCTs) of combination prevention interventions. We focus on three large C-RCTs that will start soon and are designed to test the hypothesis that combination prevention packages, including expanded access to antiretroviral therapy, can substantially reduce HIV incidence. Using a general framework to integrate mathematical modelling analysis into the design, conduct, and analysis of C-RCTs will complement traditional statistical analyses and strengthen the evaluation of the interventions. Importantly, even with combination interventions, it may be challenging to substantially reduce HIV incidence over the 2- to 3-y duration of a C-RCT, unless interventions are scaled up rapidly and key populations are reached. Thus, we propose the innovative use of mathematical modelling to conduct interim analyses, when interim HIV incidence data are not available, to allow the ongoing trials to be modified or adapted to reduce the likelihood of inconclusive outcomes. The preplanned, interactive use of mathematical models during C-RCTs will also provide a valuable opportunity to validate and refine model projections.
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HIV treatment as prevention: optimising the impact of expanded HIV treatment programmes.
PLoS Med.
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Until now, decisions about how to allocate ART have largely been based on maximising the therapeutic benefit of ART for patients. Since the results of the HPTN 052 study showed efficacy of antiretroviral therapy (ART) in preventing HIV transmission, there has been increased interest in the benefits of ART not only as treatment, but also in prevention. Resources for expanding ART in the short term may be limited, so the question is how to generate the most prevention benefit from realistic potential increases in the availability of ART. Although not a formal systematic review, here we review different ways in which access to ART could be expanded by prioritising access to particular groups based on clinical or behavioural factors. For each group we consider (i) the clinical and epidemiological benefits, (ii) the potential feasibility, acceptability, and equity, and (iii) the affordability and cost-effectiveness of prioritising ART access for that group. In re-evaluating the allocation of ART in light of the new data about ART preventing transmission, the goal should be to create policies that maximise epidemiological and clinical benefit while still being feasible, affordable, acceptable, and equitable.
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Impact of Pill Sharing on Drug Resistance Due to a Wide-Scale Oral Prep Intervention in Generalized Epidemics.
J AIDS Clin Res
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The first antiretroviral drug (Truvada) to be used as a pre-exposure prophylaxis (PrEP) in preventing HIV transmission is about to be approved. Behavioral studies suggest that a portion of users may share anti-retroviral drugs with sex partners, family, or friends. Pill sharing will decrease PrEP efficacy and adherence level, and potentially create an environment favorable for the development of drug resistance. We aim to evaluate the potential impact of pill sharing on the PrEP effectiveness and on the rates of drug-resistance development in heterosexual populations.
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Barriers to involvement of men in ANC and VCT in Khayelitsha, South Africa.
AIDS Care
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We used qualitative methods to assess pregnant women and mens attitudes, feelings, beliefs, experiences and reactions to male partners involvement in antenatal clinic (ANC) in Khayelitsha, Cape Town, South Africa. The aims of these studies were to determine barriers to male partners attendance of ANC with their pregnant female partners and to identify possible strategies to overcome these barriers. Findings from the qualitative studies demonstrated that pregnant women were keen to invite their male sexual partners and that men would attend if invited. The main barrier to male participation was lack of awareness and the healthcare facility environment. The findings of these studies emphasized the need to increase awareness among men in Khayelitsha of the need for male attendance of ANC and the need to address the barriers to male attendance of ANC. It was clear that community sensitization programmes coupled with improvement of the health facility environment to be receptive to men are essential for increasing male attendance of ANC.
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Why do condoms break? A study of female sex workers in Bangalore, south India.
Sex Transm Infect
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The purpose of the study was to obtain a better understanding of the relative importance of personal factors, male partner factors and situational factors, in determining condom breakage in a population of female sex workers (FSWs) in Bangalore.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.