Decrease In HIV Prevalence Research Articles

Patient and Provider Perceptions of Barriers and Facilitators to Pre-exposure Prophylaxis Access and Adherence in Black and Latinx Young Men Who Have Sex with Men.

In the United States, the use of pre-exposure prophylaxis (PrEP) has led to a substantial decrease in HIV prevalence and incidence. However, some populations, including young men who have sex with men (YMSM) of color, continue to be disproportionately impacted, highlighting the need for tailored interventions addressing barriers to adequate PrEP access. In collaboration with partner clinics, we recruited 19 PrEP clients and 19 PrEP providers (n = 35) to participate in hour-long in-depth interviews. Although client interviews explored personal experiences with stigma, barriers, and motivators to PrEP and information preferences, provider interviews explored providers' perceived stigma in their clinic, perceived barriers and motivators to meeting clients' PrEP needs, and rapport building with clients. Most participants were affiliated with one of the southern partner clinics. Clients and providers noted similar determinants to PrEP access, uptake, and adherence. Both recognized the impact of personal barriers such as routine adjustments and perception of need, as well as institutional barriers such as transportation and financial difficulties. Clients emphasized the role of the client-provider relationship as part of contributing to willingness to disclose information such as HIV status and sexual practices. Providers noted the importance of sexual health and LGBTQ+ topics in their training. Despite limited geographical scope and the sensitive nature of HIV-related topics, this study has several implications. PrEP clinics may benefit from hiring providers who share identities and experiences with YMSM clients of color and operating with a flexible schedule. Medical provider training should include comprehensive sexual health and LGBTQ+ competencies to reduce bias in care.

Voluntary medical male circumcision and educational gradient in relation to HIV infection among sexually active adult men in Eswatini: evidence from the national surveys in 2006-2007 and 2016.

To address knowledge gaps, this study examined social determinants, such as education attainment and HIV prevention, among sexually active men (SAM), with a focus on voluntary medical male circumcision (VMMC). Two nationally representative surveys, the Eswatini Demographic and Health Survey 2006 and the Eswatini HIV Incidence Measurement Survey 2016, were used to estimate whether or not VMMC at the individual and community levels contributes to HIV disparities to any meaningful extent. Multilevel logistic regression models further explored the educational gradient in HIV infection for 2006-2007 and 2016 with regard to VMMC among SAM, while adjusting for household poverty, sexual practices and individual characteristics. Among SAM with tertiary education, HIV prevalence declined from 25.0% in 2006-2007 to 10.5% in 2016. A 51% decrease in HIV prevalence was found to be associated with an increase in VMMC (adjusted odds ratio 0.49; 95% CI 0.40 to 0.60). Compared with SAM with tertiary education, those who had a lower level of education were more likely to have HIV infection and this education gradient effect had become particularly profound in 2016. VMMC began to be promoted in 2008 in Eswatini and results suggest its effect, along with the education attainment effect, significantly resulted in a meaningful reduction in HIV prevalence among SAM by 2016.

Prevalence trends and risk factors associated with HIV, syphilis, and hepatitis C virus among pregnant women in Southwest China, 2009–2018

ObjectiveThis study investigated prevalence trends and identified the associated factors of HIV, syphilis and hepatitis C virus (HCV) among pregnant women in the Guangxi Zhuang Autonomous Region (Guangxi), Southwest China.MethodsSerial cross-sectional surveys were performed annually among pregnant women in Guangxi from 2009 to 2018. Blood specimens were collected to test the prevalence of HIV, syphilis and HCV. Cochran–Armitage analysis was used to assess the trends of HIV, syphilis and HCV prevalence, as well as the sociodemographic and behavioural data. In this study, we used zero-inflated negative binomial (ZINB) regression models to identify factors associated with HIV, syphilis and HCV infection.ResultsA total of 23,879 pregnant women were included in the study. The prevalence of HIV, syphilis and HCV was 0.24%, 0.85% and 0.19%, respectively. There was a decrease in HIV prevalence from 0.54% to 0.10%, a decrease in HCV prevalence from 0.40% to 0.05% and a decrease in syphilis prevalence from 1.53% to 0.30%. The findings based on the ZINB model revealed that pregnant women who had a history of STI had significantly increased risks of HIV (OR 6.63; 95% CI 1.33–32.90) and syphilis (OR 9.06; 95% CI 3.85–21.30) infection, while pregnant women who were unmarried/widowed/divorced were more likely to have HIV (OR 2.81; 95% CI 1.20–6.54) and HCV (OR 58.12; 95% CI, 3.14–1076.99) infection. Furthermore, pregnant women whose husband had a history of STI (OR 5.62; 95% CI 1.24–25.38) or drug use (OR 7.36; 95% CI 1.25–43.43) showed an increased risk of HIV infection.ConclusionsThere was a relatively low prevalence of HIV, syphilis and HCV among pregnant women. Although decreasing trends in HIV, syphilis and HCV infections were observed, effort is needed to promote STI testing in both premarital medical check-ups and antenatal care, especially targeting couples with a history of STI or drug use.

Cross-sectional trends in HIV prevalence among pregnant women in Botswana: an opportunity for PrEP?

IntroductionYoung women in sub‐Saharan Africa are at particularly high risk of HIV acquisition. Recent shifts towards “test and treat” strategies have potential to reduce transmission in this age group but have not been widely studied outside of clinical trials. Using data from nationwide surveillance among pregnant women in Botswana, where a “test and treat” program was implemented in 2016, we describe trends in HIV prevalence over time and highlight opportunities for targeted prevention.MethodsThe Tsepamo study abstracted data from obstetric records of all women delivering at eight government hospitals in Botswana between 2015 and 2019, accounting for 45% of all births in the country (n = 120,755). We used a stratified analysis to identify prevalence trends and evaluated decreases in HIV prevalence over time using the Cochrane–Armitage test for linear trend. A multivariable logistic regression analysis was also performed to identify factors associated with declines in HIV prevalence.ResultsOverall HIV prevalence was 24.1% among 120,755 women who delivered during the study period. Prevalence differed by site of delivery, ranging from 16.1% to 28.2%, and increased markedly with age. Lower educational attainment (adjusted odds ratio [aOR] = 3.28; 95% confidence interval [CI] 3.07–3.50) and being unmarried (aOR = 1.98; 95% CI 1.88–2.08) were associated with HIV infection. HIV prevalence was 10.0% with a first pregnancy, 21.0% with a second and 39.2% with a third or greater (aOR = 2.20; for any prior pregnancy; 95% CI 2.10–2.29). The same age‐adjusted trends were seen when data were limited to women aged 15–24, with a two‐ to three‐fold increase in HIV prevalence between a first and third pregnancy. Prevalence decreased linearly during the 5‐year study period from 25.8% to 22.7% (p <0.001). Among age‐specific strata, the greatest absolute decline occurred in those aged 35–39, with an 8.7% absolute decrease in HIV prevalence from 2015 to 2019. Minimal declines were seen in those 15–24, with a decrease of only 1.5% over the same period.ConclusionsWhile overall trends in Botswana show HIV prevalence declining among pregnant women, prevalence among the youngest age group has remained stagnant. Preventative interventions utilizing pre‐exposure prophylaxis should be prioritized during the high‐risk period surrounding a woman's first pregnancy.

HIV prevalence and incidence among men who have sex with men and transgender women in Bangkok, 2014-2018: Outcomes of a consensus development initiative.

To reach its goal of ending AIDS by 2030, Thailand has adopted antiretroviral treatment as prevention and HIV pre-exposure prophylaxis for men who have sex with men (MSM) and transgender women (TGW) as its core HIV control strategy. However, in the absence of reliable epidemiologic indicators, the impact of these policies on the course of the HIV epidemic in these groups remains unknown. To help answer this question, we formulated an HIV epidemic consensus initiative for Bangkok, Thailand, to analyze epidemiologic and program data and reach agreement between experts and stakeholders on the evolving state of the HIV epidemic among MSM and TGW. A customized Delphi process was used to consult and consolidate viewpoints of experts and stakeholders. Experts presented and discussed HIV prevalence and incidence data from recent and ongoing studies among MSM and TGW in Bangkok (2014 to 2018) during a meeting with stakeholders representing government, donors, and civil society. Agreement about the course of the HIV epidemic among MSM and TGW was attained by voting consensus. Based on presented data, meeting participants agreed that HIV prevalence and incidence had decreased among Bangkok MSM from 2014 to 2018. Despite these declines, HIV prevalence and incidence were found to remain high. This was particularly the case among younger MSM. Participants agreed that there was no evidence for a decrease in HIV prevalence and incidence among Bangkok TGW. Introduction of antiretroviral treatment as prevention and HIV pre-exposure prophylaxis may have contributed to these declines. However, HIV prevalence and incidence remained high, and no signs of a decrease were reported among Bangkok TGW. At the current rate of new HIV infections in MSM and TGW, Thailand will not reach its goal of ending AIDS by 2030. This HIV consensus initiative may serve as a model for building agreement and advocacy on epidemiologic and program data and their implications for a large metropolitan city.

Uptake of Primary Care Services and HIV and Syphilis Infection among Transgender Women attending the Tangerine Community Health Clinic, Bangkok, Thailand, 2016 - 2019.

IntroductionTransgender women (TGW) need a specific package of primary care services usually not available in the publicly funded healthcare system. In addition, little is known about HIV and syphilis prevalence and incidence in clinic‐based samples of TGW. Here we evaluate the uptake of a transgender‐specific package of primary care services by TGW in Bangkok, Thailand and assess HIV and syphilis prevalence and incidence among them.MethodsOpen cohort study of TGW attending services at the Tangerine Community Health Clinic from 2016 to 2019. Cross‐sectional and longitudinal analysis of routinely collected clinic data was performed to study trends in the number of clients, clinic visits and HIV and syphilis prevalence and incidence.ResultsDuring the study period, 2947 TGW clients made a total of 5227 visits to Tangerine. The number of clients significantly increased from 446 in 2016 to 1050 in 2019 (p < 0.001) and the number of visits from 616 to 2198 during the same period (p < 0.001). Prevalence of HIV at first visit was 10.8% and of syphilis 9.8%. HIV incidence was 1.03 per 100 person years (PY) and of syphilis 2.06 per 100 PY of follow‐up. From 2016 to 2019, significant decreases occurred in the annual prevalence of HIV from 14.6% to 9.9% (p < 0.01). The annual prevalence of syphilis significantly increased from 6.6% in 2016 to 14.6% in 2018, and then decreased to 7.3% in 2019 (p < 0.001). The annual HIV incidence decreased during 2016 to 2019, from 1.68 to 1.28 per 100 PY, but this reduction was not statistically significant. The annual incidence of treponemal test seroconversion significantly increased from zero in 2016 to 4.55 per 100 PY in 2019 (p < 0.001).ConclusionsThe increasing uptake of a transgender‐specific package of services, including co‐located gender affirmative hormone therapy, suggests this may be an effective model in engaging and retaining TGW in primary care. The decrease in HIV prevalence and low HIV incidence across calendar years point at a possible reduction of HIV acquisition among the TGW population served by Tangerine. The increasing prevalence of syphilis suggests ongoing high‐risk sexual behaviour and underscores the need for screening and treatment for this infection at the time of delivery of HIV services.

Simulating the End of AIDS in New York: Using Participatory Dynamic Modeling to Improve Implementation of the Ending the Epidemic Initiative.

In 2014, the governor of New York announced the Ending the Epidemic (ETE) plan to reduce annual new HIV infections from 3000 to 750, achieve a first-ever decrease in HIV prevalence, and reduce AIDS progression by the end of 2020. The state health department undertook participatory simulation modeling to develop a baseline for comparing epidemic trends and feedback on ETE strategies. A dynamic compartmental model projected the individual and combined effects of 3 ETE initiatives: enhanced linkage to and retention in HIV treatment, increased preexposure prophylaxis (PrEP) among men who have sex with men, and expanded housing assistance. Data inputs for model calibration and low-, medium-, and high-implementation scenarios (stakeholders' rollout predictions, and lower and upper bounds) came from surveillance and program data through 2014, the literature, and expert judgment. Without ETE (baseline scenario), new HIV infections would decline but remain >750, and HIV prevalence would continue to increase by 2020. Concurrently implementing the 3 programs would lower annual new HIV infections by 16.0%, 28.1%, and 45.7% compared with baseline in the low-, medium-, and high-implementation scenarios, respectively. In all concurrent implementation scenarios, although annual new HIV infections would remain >750, there would be fewer new HIV infections than deaths, yielding the first-ever decrease in HIV prevalence. PrEP and enhanced linkage and retention would confer the largest population-level changes. New York State will achieve 1 ETE benchmark under the most realistic (medium) implementation scenario. Findings facilitated framing of ETE goals and underscored the need to prioritize men who have sex with men and maintain ETE's multipronged approach, including other programs not modeled here.

Declining trends in HIV and other sexually transmitted infections among female sex workers in Iran could be attributable to reduced drug injection: a cross-sectional study

ObjectiveThe HIV trend among female sex workers (FSWs) is understudied. We assessed the prevalence and trend of HIV and five other STIs among FSWs in Iran.MethodsWe recruited FSWs (1337 in...

HIV and hepatitis C virus infections in Quebec’s provincial detention centres: comparing prevalence and related risky behaviours between 2003 and 2014-2015

To compare the prevalence of HIV, hepatitis C virus (HCV) infections, and related risky behaviours among inmates in Quebec's provincial prisons between 2003 and 2014-2015. Cross-sectional data were anonymously collected from May 2014 to March 2015 for men (n = 1315) and women (n = 250) and combined with data collected in 2003 to evaluate trends in the last decade. Participants completed a questionnaire and provided saliva samples. The data from the 2003 and 2014-2015 surveys were merged for statistical analysis. HIV prevalence was stable between 2003 and 2014-2015 for men (2.4% vs. 1.8%, p = 0.4), whereas it decreased for women (8.8% vs. 0.8%, p < 0.001). HCV prevalence decreased between 2003 and 2014-2015 for both men (16.6% vs. 11.9%, p < 0.001) and women (29.2% vs. 19.2%, p = 0.02). HIV and HCV prevalence were higher among people who inject drugs (PWID), for both sexes and both studies. PWID-specific prevalence did not change between 2003 and 2014-2015, except for a decrease in HIV prevalence in PWID women. However, the proportion of prisoners reporting a history of injection drug use outside prison was lower in 2014-2015 than in 2003 for men (19.8% vs. 27.7%, p < 0.0001) and women (28.6% vs. 42.6%, p = 0.002). The lower proportion of PWID inmates in 2014-2015 compared to 2003 explained in large part the decrease in HIV and HCV prevalence. Despite the decrease in prevalence, HIV and HCV infections among incarcerated individuals still represent a major public health problem due to the sizable increase of individuals in Quebec's correctional system over the same period.

HIV decline associated with changes in risk behaviours among young key populations in Nepal: analysis of population-based HIV prevalence surveys between 2001 and 2012.

We assessed changes in HIV prevalence and risk behaviours among young key populations in Nepal. A total of 7505 participants (aged 16-24 years) from key populations who were at increased risk of HIV infection (2767 people who inject drugs (PWID); 852 men who have sex with men/transgender (MSM/TG); 2851 female sex workers (FSW) and 1035 male labour migrants) were recruited randomly over a 12-year period, 2001-2012. Local epidemic zones of Nepal (Kathmandu valley, Pokhara valley, Terai Highway and West to Far West hills) were analysed separately. We found a very strong and consistent decline in HIV prevalence over the past decade in different epidemic zones among PWID and MSM/TG in Kathmandu, the capital city, most likely due to a parallel increase in safe needle and syringe use and increased condom use. A decrease in HIV prevalence in 22 Terai highway districts, sharing an open border with India, was also consistent with increased condom use among FSW. Among male labour migrants, HIV prevalence was low throughout the period in the West to Far West hilly regions. Condom use by migrant workers involved with FSW abroad increased while their condom use with Nepalese FSW declined. Other risk determinants such as mean age at starting first injection, injection frequency, place of commercial sex solicitation, their mean age when leaving to work abroad did not change consistently across epidemic zones among the young key populations under study. In Nepal, the decline in HIV prevalence over the past decade was remarkably significant and consistent with an increase in condom use and safer use of clean needles and syringes. However, diverging trends in risk behaviours across local epidemic zones of Nepal suggest a varying degree of implementation of national HIV prevention policies. This calls for continued preventive efforts as well as surveillance to sustain the observed downward trend.

Implementing quality assurance for laboratory-based and point-of-care HIV testing in Nigeria.

No abstract available.

Investing in the health workforce to increase access to and use of HIV and AIDS services in Uganda.

Despite progress over the last decade, Uganda's achievement of key health indicators, including for HIV and AIDS, remains unsatisfactory and continues to represent leading causes of morbidity and mortality [1]. As the Government of Uganda works to improve healthcare across all service delivery areas, HIV and AIDS receives heightened attention because of the country's ranking in terms of the number of new HIV infections, people living with HIV (PLHIV), AIDS-related deaths, and adult HIV prevalence rate [2]. Intensive efforts in HIV prevention, care, and treatment led to a decrease in HIV prevalence from a high of 18% in the 1990s to 6.4% in 2002. After persisting at this level from 2002 to 2007, HIV prevalence rose to a national average of 7.3% (2011) [3,4]. Many regions experience an even higher burden of HIV, especially in central and mid-northern Uganda, with prevalence ranging from 8.3 to 10.6% [4]. Health workforce challenges undermine HIV service delivery Uganda's aim to strengthen and scale up its HIV and AIDS response to reduce new infections and achieve ‘a population free of HIV and its effects’ [5] is undermined by low utilization of health services and perceived low quality of healthcare [6]. A key element of quality service delivery and demand is a well performing and well trained health workforce [7]. Uganda's absolute shortage and inadequate geographic distribution of health workers with appropriate skill mix to provide services across the continuum hinders achievement of epidemic control. A national staff audit conducted by the Ministry of Health in 2009 found that 47% of established positions in government health facilities were vacant [8]. In addition, about 71% of doctors and 41% of nurses and midwives were working in urban areas, although 85% of the population reside in rural areas [9,10]. Factors contributing to high health worker vacancy and low retention include weak leadership and management, inadequate planning and human resources management systems, low levels of motivation, and poor working and living conditions in rural areas [6]. To address health workforce challenges affecting quality of care for HIV and AIDS, the United States Agency for International Development (USAID) and U.S. President's Emergency Plan for AIDS Relief-funded global CapacityPlus project and bilateral Uganda Capacity Program (UCP), both led by IntraHealth International, worked in close collaboration with the Ministry of Health to strengthen health workforce management to enable improved delivery of quality HIV and AIDS services. They also provided family planning, reproductive health and other health services with funding from PEPFAR and USAID's Population and Reproductive Health, Maternal and Child Health, and other programs. This field note describes selected interventions from a more comprehensive package of human resources management support provided to the Ministry of Health, to improve the utilization of data for evidence-based planning, deployment, and management of the health workforce. It also provides an example of how health workforce data can be analyzed alongside country-level HIV service statistics to ensure an adequate supply of human resources for health (HRH) where increased accessibility and scale-up of HIV services is needed to achieve 90–90–90 goals [11–13].

Association of sexual risk behaviour with previous HIV testing among voluntary HIV counselling and testing clients in Kigali, Rwanda.

With increased coverage of voluntary HIV counselling and testing (VCT) in Rwanda and a greater focus on repeat testing of key populations, it is important to understand whether the right clients are returning for repeat testing and if repeat testing is effective at reducing risk. We assessed the association between repeat testing and recent sexual risk behaviours among 1852 first time or repeat HIV testing clients in Kigali who had had sex, using data from a cross-sectional survey. Repeat testing was associated with being female, older and type of occupation. Multivariable analyses indicate that individuals who tested for HIV 1-2 times (aOR = 1.52, 95% CI: 1.08, 2.15) and 3+ times (aOR = 1.51, 95% CI: 1.06, 2.17) previously were more likely to report recent unprotected sex. Those with 3+ previous tests were more likely to have recently had multiple sexual partners (aOR = 2.19, 95% CI: 1.22, 3.92). However, a significant decrease in HIV prevalence is shown as individuals receive more HIV tests in their lifetime (p < 0.001). These findings show that individuals who report high-risk behaviours are returning for repeat tests. However, VCT may not be successful at addressing certain sexual risk behaviours. Therefore more intensive counselling or additional HIV prevention services may be needed.

Parallel declines in HIV and hepatitis C virus prevalence, but not in herpes simplex virus type 2 infection: A 10-year, serial cross-sectional study in an inner-city emergency department

BackgroundThe Johns Hopkins Hospital Emergency Department (JHHED) has served as an observational window on the HIV epidemic in a socioeconomically depressed, urban population. We previously reported that HIV incidence among JHHED patients is decreasing and that prevalence has declined from 11.4% in 2003–5.6% in 2013. ObjectivesThis study sought to observe temporal trends in hepatitis C virus (HCV) and herpes simplex virus type 2 (HSV-2) seroprevalence, which are surrogate markers for parenteral and sexual risk behavior, respectively. Study designIdentity unlinked-serosurveys were conducted over 6–8 weeks in the adult JHHED in 2003, 2007, and 2013. Excess sera from 10,274 patients, previously tested for HIV, were assayed for HSV-2 and HCV antibodies. ResultsOverall HCV seroprevalence declined steadily from 22.0% in 2003–13.8% in 2013 (Ptrend<0.01), and was significant by all gender and race strata. Overall HSV-2 prevalence declined from 55.3% in 2003–50.0% in 2013 (Ptrend<0.01), but was non-significant after adjustment for demographics. Among HIV+ individuals<45years of age, there was a significant decrease in the proportion of individuals with HCV co-infection [without HSV-2] (Ptrend=0.02) from 2003 to 2013, however, there was an increase in individuals with HSV-2 co-infection [without HCV] (Ptrend < 0.01). DiscussionLittle change in age-specific HSV-2 prevalence suggests the decrease in HIV prevalence was likely not associated with changes in sexual risk behavior. In addition to clinical interventions, strategies to address sexual health disparities and continued parenteral harm-reduction efforts are needed to further drive the decline in HIV.

Determinantes estructurales de países con decrecimiento en la prevalencia por la infección VIH/SIDA en el periodo 2001-2011

The present study aims analyze and compare structural features in order to establish a model about the decline in HIV/AIDS infection (greater than or equal to 25 %) in twenty-two countries between 2001 and 2011. Retrospective cohort focused on social determinants of health perspective. The methodology was mainly documentary (epidemic behavior) and quantitative (simple linear regression model for economic and health variables). The major indicators that influence the decrease in the prevalence of HIV are: GDP per capita, health expenditure per capita and the Gini index Structural determinants, as well as inequities, may or not influence the decrease in prevalence of HIV. This hypothesis could be applied to other public health issues.

HIV Epidemic in Asia: Implications for HIV Vaccine and Other Prevention Trials.

An overall decrease of HIV prevalence is now observed in several key Asian countries due to effective prevention programs. The decrease in HIV prevalence and incidence may further improve with the scale-up of combination prevention interventions. The implementation of future prevention trials then faces important challenges. The opportunity to identify heterosexual populations at high risk such as female sex workers may rapidly wane. With unabating HIV epidemics among men who have sex with men (MSM) and transgender (TG) populations, an effective vaccine would likely be the only option to turn the epidemic. It is more likely that efficacy trials will occur among MSM and TG because their higher HIV incidence permits smaller and less costly trials. The constantly evolving patterns of HIV-1 diversity in the region suggest close monitoring of the molecular HIV epidemic in potential target populations for HIV vaccine efficacy trials. CRF01_AE remains predominant in southeast Asian countries and MSM populations in China. This relatively steady pattern is conducive to regional efficacy trials, and as efficacy warrants, to regional licensure. While vaccines inducing nonneutralizing antibodies have promise against HIV acquisition, vaccines designed to induce broadly neutralizing antibodies and cell-mediated immune responses of greater breadth and depth in the mucosal compartments should be considered for testing in MSM and TG. The rationale and design of efficacy trials of combination prevention modalities such as HIV vaccine and preexposure prophylaxis (PrEP) remain hypothetical, require high adherence to PrEP, are more costly, and present new regulatory challenges. The prioritization of prevention interventions should be driven by the HIV epidemic and decided by the country-specific health and regulatory authorities. Modeling the impact and cost-benefit may help this decision process.

Could there have been substantial declines in sexual risk behavior across sub-Saharan Africa in the mid-1990s?

BackgroundHIV prevalence is decreasing in much of sub-Saharan Africa (SSA), but the drivers of the decline are subject to much dispute. Using mathematical modeling as a tool for hypothesis generation, we demonstrate how the hypothesis that the drop in prevalence reflects declines in sexual risk behavior is self-consistent. We characterize these potential declines in terms of their scale, duration, and timing, and theorize on how small changes in sexual behavior at the individual-level could have driven large declines in HIV prevalence. Materials and methodsA population-level deterministic compartmental model was constructed to describe the HIV epidemics in 24 countries in SSA with sufficient trend data. The model was parameterized by national HIV prevalence and HIV natural history and transmission data. The temporal evolution of sexual risk behavior was characterized using established tools and uncertainty and sensitivity analyses on the results were conducted. ResultsDeclines in the scale of sexual risk behavior between 31.8% (Botswana) and 89.3% (Liberia) can explain the declining HIV prevalence across countries. The average decline across countries was 68.9%. The transition in sexual risk behavior lasted between 2.7 (Botswana) and 16.6 (Gabon) years with an average of 8.2 years. The turning point year of the transition occurred between 1993 (Burundi) and 2001 (Namibia), but clustered around 1995 for most countries. The uncertainty and sensitivity analyses affirmed our model predictions. ConclusionThe hypothesis that HIV prevalence declines in SSA have been driven by declines in sexual risk behavior is self-consistent and provides a convincing narrative for an evolving HIV epidemiology in this region. The hypothesized declines must have been remarkable in their intensity, rapidity, and synchronicity to explain the temporal trends in HIV prevalence. These findings provide contextual support for the hypothesis that changes in sexual behavior that materialized in the 1990s are a dominant driver of the recent decreases in HIV prevalence.

Effectiveness of structural-level needle/syringe programs to reduce HCV and HIV infection among people who inject drugs: a systematic review.

Needle-syringe programs (NSP) have been effective in reducing HIV and hepatitis C (HCV) infection among people who inject drugs (PWID). Achieving sustainable reductions in these blood-borne infections requires addressing structural factors so PWID can legally access NSP services. Systematic literature searches collected information on NSP coverage and changes in HIV or HCV infection prevalence or incidence at the population level. Included studies had to document biomarkers (HIV or HCV) coupled with structural-level NSP, defined by a minimum 50% coverage of PWID and distribution of 10 or more needles/syringe per PWID per year. Fifteen studies reported structural-level NSP and changes in HIV or HCV infection prevalence/incidence. Nine reported decreases in HIV prevalence, six in HCV infection prevalence, and three reported decreases in HIV incidence. The results support NSP as a structural-level intervention to reduce population-level infection and implementation of NSP for prevention and treatment of HIV and HCV infection.

Condom negotiation across different relationship types by young women engaged in sex work in Phnom Penh, Cambodia

Cambodia's 100% Condom Use Programme is credited with an increase in consistent condom use in commercial sexual interactions and a decrease in HIV prevalence among female sex workers (FSWs). There has been little improvement in condom use between FSWs and non-commercial partners, prompting calls for more innovative approaches to increasing condom use in these relationships. To understand why condoms are used or not used in sexual interactions involving FSWs, we examined condom negotiation across different types of relationships. We conducted 33 in-depth interviews with young (15 to 29 years) women engaged in sex work in Phnom Penh. There was an important interplay between the meanings of condom use and the meanings of women's relationships. Commercial relationships were characterised as inherently risky and necessitated condom use. Despite a similar lack of sexual fidelity, sweetheart relationships were rarely construed as risky and typically did not involve condom use. Husbands and wives constructed their sexual interactions with each other differently, making agreement on condom use difficult. The lack of improvement in condom use in FSWs' non-commercial sexual relationships needs to be understood in relation to both sex work and the broader Cambodian sexual culture within which these relationships are embedded.

A complex systems approach to evaluate HIV prevention in metropolitan areas: preliminary implications for combination intervention strategies.

BackgroundHIV transmission among injecting and non-injecting drug users (IDU, NIDU) is a significant public health problem. Continuing propagation in endemic settings and emerging regional outbreaks have indicated the need for comprehensive and coordinated HIV prevention. We describe the development of a conceptual framework and calibration of an agent-based model (ABM) to examine how combinations of interventions may reduce and potentially eliminate HIV transmission among drug-using populations.Methodology/Principal FindingsA multidisciplinary team of researchers from epidemiology, sociology, geography, and mathematics developed a conceptual framework based on prior ethnographic and epidemiologic research. An ABM was constructed and calibrated through an iterative design and verification process. In the model, “agents” represent IDU, NIDU, and non-drug users who interact with each other and within risk networks, engaging in sexual and, for IDUs, injection-related risk behavior over time. Agents also interact with simulated HIV prevention interventions (e.g., syringe exchange programs, substance abuse treatment, HIV testing) and initiate antiretroviral treatment (ART) in a stochastic manner. The model was constructed to represent the New York metropolitan statistical area (MSA) population, and calibrated by comparing output trajectories for various outcomes (e.g., IDU/NIDU prevalence, HIV prevalence and incidence) against previously validated MSA-level data. The model closely approximated HIV trajectories in IDU and NIDU observed in New York City between 1992 and 2002, including a linear decrease in HIV prevalence among IDUs. Exploratory results are consistent with empirical studies demonstrating that the effectiveness of a combination of interventions, including syringe exchange expansion and ART provision, dramatically reduced HIV prevalence among IDUs during this time period.Conclusions/SignificanceComplex systems models of adaptive HIV transmission dynamics can be used to identify potential collective benefits of hypothetical combination prevention interventions. Future work will seek to inform novel strategies that may lead to more effective and equitable HIV prevention strategies for drug-using populations.