962 research outputs found

    Can the UNAIDS modes of transmission model be improved? A comparison of the original and revised model projections using data from a setting in west Africa.

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    OBJECTIVE: The UNAIDS modes of transmission model (MoT) is a user-friendly model, developed to predict the distribution of new HIV infections among different subgroups. The model has been used in 29 countries to guide interventions. However, there is the risk that the simplifications inherent in the MoT produce misleading findings. Using input data from Nigeria, we compare projections from the MoT with those from a revised model that incorporates additional heterogeneity. METHODS: We revised the MoT to explicitly incorporate brothel and street-based sex-work, transactional sex, and HIV-discordant couples. Both models were parameterized using behavioural and epidemiological data from Cross River State, Nigeria. Model projections were compared, and the robustness of the revised model projections to different model assumptions, was investigated. RESULTS: The original MoT predicts 21% of new infections occur in most-at-risk-populations (MARPs), compared with 45% (40-75%, 95% Crl) once additional heterogeneity and updated parameterization is incorporated. Discordant couples, a subgroup previously not explicitly modelled, are predicted to contribute a third of new HIV infections. In addition, the new findings suggest that women engaging in transactional sex may be an important but previously less recognized risk group, with 16% of infections occurring in this subgroup. CONCLUSION: The MoT is an accessible model that can inform intervention priorities. However, the current model may be potentially misleading, with our comparisons in Nigeria suggesting that the model lacks resolution, making it challenging for the user to correctly interpret the nature of the epidemic. Our findings highlight the need for a formal review of the MoT

    Increasing incidence of anogenital warts with an urban–rural divide among males in Manitoba, Canada, 1990–2011

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    Abstract Background Anogenital warts (AGW) are caused by the most common sexually transmitted infection, human papillomavirus. The objective of this study was to examine AGW incidence from 1990 to 2011 by sex, age, income quintile, and residential area category (urban/rural). The study period included the initiation of school-based HPV vaccination for girls in the sixth grade, which began in 2008. The data presented in this paper may also be useful for establishing baseline rates of AGW incidence which may be used to evaluate the success of the school-based HPV immunization program. Methods Cases of anogenital warts were identified using Manitoba’s administrative databases of Physician Claims and Hospital Discharge Abstracts. Annual age-standardized incidence in Manitoba from 1990 to 2011 was calculated. Incident AGW rates were compared by sex, age group, residential area category (urban/rural), and household income quintile using logistic regression. Joinpoint regression analyses were used to evaluate the time trends of AGW. Results Prior to 2000, AGW incidence was higher among females than males. However, from 2000 to 2011 the incidence was higher among males and increased steadily over time. AGW incidence tended to peak in younger age groups among females compared to males. Females and males living in urban areas had nearly twice the odds of AGW occurrence compared to those in rural areas. Conclusions There is a need for education about AGW in male population. The upcoming initiation of HPV vaccination among boys may reduce the incidence and should be evaluated

    Constraining Primordial Non-Gaussianity With the Abundance of High Redshift Clusters

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    We show how observations of the evolution of the galaxy cluster number abundance can be used to constrain primordial non-Gaussianity in the universe. We carry out a maximum likelihood analysis incorporating a number of current datasets and accounting for a wide range of sources of systematic error. Under the assumption of Gaussianity, the current data prefer a universe with matter density Ωm0.3\Omega_m\simeq 0.3 and are inconsistent with Ωm=1\Omega_m=1 at the 2σ2\sigma level. If we assume Ωm=1\Omega_m=1, the predicted degree of cluster evolution is consistent with the data for non-Gaussian models where the primordial fluctuations have at least two times as many peaks of height 3σ3\sigma or more as a Gaussian distribution does. These results are robust to almost all sources of systematic error considered: in particular, the Ωm=1\Omega_m=1 Gaussian case can only be reconciled with the data if a number of systematic effects conspire to modify the analysis in the right direction. Given an independent measurement of Ωm\Omega_m, the techniques described here represent a powerful tool with which to constrain non-Gaussianity in the primordial universe, independent of specific details of the non-Gaussian physics. We discuss the prospects and strategies for improving the constraints with future observations.Comment: Minor revisions to match published ApJ version, 14 pages emulateap

    Supporting adolescent girls to stay in school, reduce child marriage and reduce entry into sex work as HIV risk prevention in north Karnataka, India: protocol for a cluster randomised controlled trial.

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    BACKGROUND: Low caste adolescent girls living in rural northern Karnataka are at increased risk of school drop-out, child marriage, and entry into sex-work, which enhances their vulnerability to HIV, early pregnancy and adverse maternal and child health outcomes. This protocol describes the evaluation of Samata, a comprehensive, multi-level intervention designed to address these structural drivers of HIV risk and vulnerability. METHODS/DESIGN: The Samata study is a cluster randomised controlled trial that will be conducted in eighty village clusters (40 intervention; 40 control) in Bijapur and Bagalkot districts in northern Karnataka. The intervention seeks to reach low caste girls and their families; adolescent boys; village communities; high school teachers and school governing committees; and local government officials. All low caste (scheduled caste/tribe) adolescent girls attending 7th standard (final year of primary school) will be recruited into the study in two consecutive waves, one year apart. Girls (n = 2100), their families (n = 2100) and school teachers (n = 650) will be interviewed at baseline and at endline. The study is designed to assess the impact of the intervention on four primary outcomes: the proportion of low caste girls who (i) enter into secondary school; (ii) complete secondary school; (iii) marry before age 15; and (iv) engage in sex before age 15. Observers assessing the outcomes will be blinded to group assignment. The primary outcome will be an adjusted, cluster-level intention to treat analysis, comparing outcomes in intervention and control villages at follow-up. We will also conduct survival analyses for the following secondary outcomes: marriage, sexual debut, pregnancy and entry into sex work. Complementary monitoring and evaluation, qualitative and economic research will be used to explore and describe intervention implementation, the pathways through which change occurs, and the cost-effectiveness of the intervention. DISCUSSION: This is an innovative trial of a comprehensive intervention to improve the quality of life and reduce HIV vulnerability among marginalised girls in northern Karnataka. The findings will be of interest to programme implementers, policy makers and evaluation researchers working in the development, education, and sexual and reproductive health fields. TRIAL REGISTRATION: ClinicalTrials.Gov NCT01996241 . 16th November 2013

    Cosmic Microwave Background Polarization

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    Cosmic microwave background (CMB) anisotropy is our richest source of cosmological information; the standard cosmological model was largely established thanks to study of the temperature anisotropies. By the end of the decade, the Planck satellite will close this important chapter and move us deeper into the new frontier of polarization measurements. Numerous ground--based and balloon--borne experiments are already forging into this new territory. Besides providing new and independent information on the primordial density perturbations and cosmological parameters, polarization measurements offer the potential to detect primordial gravity waves, constrain dark energy and measure the neutrino mass scale. A vigorous experimental program is underway worldwide and heading towards a new satellite mission dedicated to CMB polarization.Comment: Review given at TAUP 2005; References added; Additional reference

    Changes in risk behaviours and prevalence of sexually transmitted infections following HIV preventive interventions among female sex workers in five districts in Karnataka state, south India

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    OBJECTIVES: To examine the impact of a large-scale HIV prevention programme for female sex workers (FSW) in Karnataka state, south India, on the prevalence of HIV/sexually transmitted infections (STI), condom use and programme coverage. METHODS: Baseline and follow-up integrated biological and behavioural surveys were conducted on random samples of FSW in five districts in Karnataka between 2004 and 2009. RESULTS: 4712 FSW participated in the study (baseline 2312; follow-up 2400), with follow-up surveys conducted 28-37 months after baseline. By follow-up, over 85% of FSW reported contact by a peer educator and having visited a project STI clinic. Compared with baseline, there were reductions in the prevalence of HIV (19.6% vs 16.4%, adjusted odds ratio (AOR) 0.81, 95% CI 0.67 to 0.99, p=0.04); high-titre syphilis (5.9% vs 3.4%, AOR 0.53, 95% CI 0.37 to 0.77, p=0.001); and chlamydia and/or gonorrhoea (8.9% vs 7.0%, AOR 0.72, 95% CI 0.54 to 0.94, p=0.02). Reported condom use at last sex increased significantly for repeat clients (66.1% vs 84.1%, AOR 1.98, 95% CI 1.58 to 2.48, p<0.001) and marginally for occasional clients (82.9% vs 88.0%, AOR 1.22, 95% CI 0.89 to 1.66, p=0.2), but remained stable for regular partners (32%). Compared with street and home-based FSW, brothel-based FSW were at highest risk of HIV and STI, despite high levels of reported condom use. CONCLUSIONS: This large-scale HIV prevention programme for FSW achieved reductions in HIV and STI prevalence, high rates of condom use with clients and high rates of programme coverage. Improved strategies to increase condom use with regular partners and reduce the vulnerability of brothel-based FSW to HIV are required

    An integrated structural intervention to reduce vulnerability to HIV and sexually transmitted infections among female sex workers in Karnataka state, south India

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    BACKGROUND: Structural factors are known to affect individual risk and vulnerability to HIV. In the context of an HIV prevention programme for over 60,000 female sex workers (FSWs) in south India, we developed structural interventions involving policy makers, secondary stakeholders (police, government officials, lawyers, media) and primary stakeholders (FSWs themselves). The purpose of the interventions was to address context-specific factors (social inequity, violence and harassment, and stigma and discrimination) contributing to HIV vulnerability. We advocated with government authorities for HIV/AIDS as an economic, social and developmental issue, and solicited political leadership to embed HIV/AIDS issues throughout governmental programmes. We mobilised FSWs and appraised them of their legal rights, and worked with FSWs and people with HIV/AIDS to implement sensitization and awareness training for more than 175 government officials, 13,500 police and 950 journalists. METHODS: Standardised, routine programme monitoring indicators on service provision, service uptake, and community activities were collected monthly from 18 districts in Karnataka between 2007 and 2009. Daily tracking of news articles concerning HIV/AIDS and FSWs was undertaken manually in selected districts between 2005 and 2008. RESULTS: The HIV prevention programme is now operating at scale, with over 60,000 FSWs regularly contacted by peer educators, and over 17,000 FSWs accessing project services for sexually transmitted infections monthly. FSW membership in community-based organisations has increased from 8,000 to 37,000, and over 46,000 FSWs have now been referred for government-sponsored social entitlements. FSWs were supported to redress > 90% of the 4,600 reported incidents of violence and harassment reported between 2007-2009, and monitoring of news stories has shown a 50% increase in the number of positive media reports on HIV/AIDS and FSWs. CONCLUSIONS: Stigma, discrimination, violence, harassment and social equity issues are critical concerns of FSWs. This report demonstrates that it is possible to address these broader structural factors as part of large-scale HIV prevention programming. Although assessing the impact of the various components of a structural intervention on reducing HIV vulnerability is difficult, addressing the broader structural factors contributing to FSW vulnerability is critical to enable these vulnerable women to become sufficiently empowered to adopt the safer sexual behaviours which are required to respond effectively to the HIV epidemic

    Changes in HIV and syphilis prevalence among female sex workers from three serial cross-sectional surveys in Karnataka state, South India.

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    OBJECTIVES: This paper examined trends over time in condom use, and the prevalences of HIV and syphilis, among female sex workers (FSWs) in South India. DESIGN: Data from three rounds of cross-sectional surveys were analysed, with HIV and high-titre syphilis prevalence as outcome variables. Multivariable analysis was applied to examine changes in prevalence over time. SETTING: Five districts in Karnataka state, India. PARTICIPANTS: 7015 FSWs were interviewed over three rounds of surveys (round 1=2277; round 2=2387 and round 3=2351). Women who reported selling sex in exchange for money or gifts in the past month, and aged between 18 and 49 years, were included. INTERVENTIONS: The surveys were conducted to monitor a targeted HIV prevention programme during 2004-2012. The main interventions included peer-led community outreach, services for the treatment and prevention of sexually transmitted infections, and empowering FSWs through community mobilisation. RESULTS: HIV prevalence declined significantly from rounds 1 to 3, from 19.6% to 10.8% (adjusted OR (AOR)=0.48, p<0.001); high-titre syphilis prevalence declined from 5.9% to 2.4% (AOR=0.50, p<0.001). Reductions were observed in most substrata of FSWs, although reductions among new sex workers, and those soliciting clients using mobile phones or from home, were not statistically significant. Condom use 'always' with occasional clients increased from 73% to 91% (AOR=1.9, p<0.001), with repeat clients from 52% to 86% (AOR=5.0, p<0.001) and with regular partners from 12% to 30% (AOR=4.2, p<0.001). Increased condom use was associated with exposure to the programme. However, condom use with regular partners remained low. CONCLUSIONS: The prevalences of HIV infection and high-titre syphilis among FSWs have steadily declined with increased condom use. Further reductions in prevalence will require intensification of prevention efforts for new FSWs and those soliciting clients using mobile phones or from home, as well as increasing condom use in the context of regular partnerships
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