Modeling the Intervention of HIV Transmission across Intertwined Key Populations.
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ABSTRACT:
SUBMITTER: Zhong L
PROVIDER: S-EPMC5799486 | biostudies-literature | 2018 Feb
REPOSITORIES: biostudies-literature
Publications
Modeling the Intervention of HIV Transmission across Intertwined Key Populations.
Zhong Lu L Zhang Qingpeng Q Li Xiaoming X
Scientific reports 20180205 1
The HIV transmissions between multiple key populations make interventions difficult, particularly with multiple transmission behaviors. It remains unclear how significant the role of bridge individuals (who connect multiple communities) is in HIV transmission, and how to develop more effective intervention strategies targeting different transmission modes across key populations. In this research, we proposed a 2-layer social network framework to simulate the HIV transmissions across female sex w ...[more]
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Project description:IntroductionIn generalized epidemic settings, there is insufficient understanding of how the unmet HIV prevention and treatment needs of key populations (KPs), such as female sex workers (FSWs) and men who have sex with men (MSM), contribute to HIV transmission. In such settings, it is typically assumed that HIV transmission is driven by the general population. We estimated the contribution of commercial sex, sex between men, and other heterosexual partnerships to HIV transmission in South Africa (SA).MethodsWe developed the "Key-Pop Model"; a dynamic transmission model of HIV among FSWs, their clients, MSM, and the broader population in SA. The model was parameterized and calibrated using demographic, behavioural and epidemiological data from national household surveys and KP surveys. We estimated the contribution of commercial sex, sex between men and sex among heterosexual partnerships of different sub-groups to HIV transmission over 2010 to 2019. We also estimated the efficiency (HIV infections averted per person-year of intervention) and prevented fraction (% IA) over 10-years from scaling-up ART (to 81% coverage) in different sub-populations from 2020.ResultsSex between FSWs and their paying clients, and between clients with their non-paying partners contributed 6.9% (95% credibility interval 4.5% to 9.3%) and 41.9% (35.1% to 53.2%) of new HIV infections in SA over 2010 to 2019 respectively. Sex between low-risk groups contributed 59.7% (47.6% to 68.5%), sex between men contributed 5.3% (2.3% to 14.1%) and sex between MSM and their female partners contributed 3.7% (1.6% to 9.8%). Going forward, the largest population-level impact on HIV transmission can be achieved from scaling up ART to clients of FSWs (% IA = 18.2% (14.0% to 24.4%) or low-risk individuals (% IA = 20.6% (14.7 to 27.5) over 2020 to 2030), with ART scale-up among KPs being most efficient.ConclusionsClients of FSWs play a fundamental role in HIV transmission in SA. Addressing the HIV prevention and treatment needs of KPs in generalized HIV epidemics is central to a comprehensive HIV response.
| S-EPMC7855076 | biostudies-literature
Project description:Tijuana, Mexico, has a concentrated HIV epidemic among overlapping key populations (KPs) including people who inject drugs (PWID), female sex workers (FSW), their male clients, and men who have sex with men (MSM). We developed a dynamic HIV transmission model among these KPs to determine the extent to which their unmet prevention and treatment needs is driving HIV transmission. Over 2020-2029 we estimated the proportion of new infections acquired in each KP, and the proportion due to their unprotected risk behaviours. We estimate that 43.7% and 55.3% of new infections are among MSM and PWID, respectively, with FSW and their clients making-up < 10% of new infections. Projections suggest 93.8% of new infections over 2020-2029 will be due to unprotected sex between MSM or unsafe injecting drug use. Prioritizing interventions addressing sexual and injecting risks among MSM and PWID are critical to controlling HIV in Tijuana.
| S-EPMC8560668 | biostudies-literature
Project description:BackgroundTo achieve reductions in HIV incidence, we need strategies to engage key population at risk for HIV in low-income and middle-income countries. We evaluated the effectiveness of integrated care centres in India that provided single-venue HIV testing, prevention, and treatment services for people who inject drugs (PWID) and men who have sex with men (MSM).MethodsWe did baseline respondent-driven sampling surveys in 27 sites across India, and selected 22 of these (12 PWID and ten MSM) for a cluster randomised trial on the basis of high HIV prevalence and logistical considerations. We used stratified (by PWID and MSM), restricted randomisation to allocate sites to either the integrated care intervention or usual care (11 sites per group). We implemented integrated care centres in 11 cities (six PWID integrated care centres embedded within opioid agonist treatment centres and five MSM centres within government-sponsored health services), with a single integrated care centre per city in all but one city. After a 2-year intervention phase, we did respondent-driven sampling evaluation surveys of target population members who were aged 18 years or older at all sites. The primary outcome was self-reported HIV testing in the previous 12 months (recent testing), determined via the evaluation survey. We used a biometric identification system to estimate integrated care centre exposure (visited an integrated care centre at least once) among evaluation survey participants at intervention sites. This trial is registered with ClinicalTrials.gov, number NCT01686750.FindingsBetween Oct 1, 2012, and Dec 19, 2013, we recruited 11 993 PWID and 9997 MSM in the baseline survey and, between Aug, 1 2016, and May 27, 2017, surveyed 11 721 PWID and 10 005 MSM in the evaluation survey using respondent-driven sampling, across the 22 trial sites. During the intervention phase, integrated care centres provided HIV testing for 14 698 unique clients (7630 PWID and 7068 MSM. In the primary population-level analysis, recent HIV testing was 31% higher at integrated care centres than at usual care sites (adjusted prevalence ratio [PR] 1·31, 95% CI 0·95-1·81, p=0·09). Among survey participants at intervention sites, integrated care centre exposure was lower than expected (median exposure 40% at PWID sites and 24% at MSM sites). In intervention sites, survey participants who visited an integrated care centre were more likely to report recent HIV testing than were participants who had not (adjusted PR 3·46, 2·94-4·06).InterpretationAlthough integrated care centres increased HIV testing among visitors, our low exposure findings suggest that the scale-up of a single integrated care centre in most cities was insufficient to serve the large PWID and MSM populations. Future work should address the use of population size estimates to guide the dose of combination HIV interventions targeting key populations.FundingUS National Institutes of Health and the Elton John AIDS Foundation.
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Project description:Adolescents and young adults are at increased risk for HIV due to the many developmental, psychological, social, and structural transitions that converge in this period of the lifespan. In addition, adolescent deaths resulting from HIV continue to rise despite declines in other age groups. There are also young key populations (YKPs) that bear disproportionate burdens of HIV and are the most vulnerable, including young men who have sex with men (MSM), transgender youth, young people who inject drugs, and adolescent and young adult sex workers. As a society, we must do more to stop new HIV infections and untimely HIV-related deaths through both primary and secondary prevention and better management approaches. Using an interwoven prevention and treatment cascade approach, the starting point for all interventions must be HIV counselling and testing. Subsequent interventions for both HIV-negative and HIV-positive youth must be “adolescent-centred,” occur within the socio-ecological context of young people and take advantage of the innovations and technologies that youth have easily incorporated into their daily lives. In order to achieve the global goals of zero infections, zero discrimination and zero deaths, a sustained focus on HIV research, policy and advocacy for YKPs must occur.
| S-EPMC4581085 | biostudies-literature
Project description:Prisons and other closed facilities create opportunities for transmission of human immunodeficiency virus (HIV) and viral hepatitis during detention and after release. We conducted a systematic review and meta-analysis of peer-reviewed publications (2005-2015) to describe the prevalence of HIV, hepatitis C virus, and hepatitis B virus among key populations in prisons worldwide and to compare estimates of infection with those of other prison populations. Most data were reported for people who inject drugs (PWID; n = 72) and for men who have sex with men (MSM; n = 21); few data were reported on sex workers (SW; n = 6), or transgender women (n = 2). Publications were identified from 29 countries, predominantly middle- and high-income countries. Globally, PWID had 6 times the prevalence of HIV (pooled prevalence ratio (PPR) = 6.0, 95% CI: 3.8, 9.4), 8 times the prevalence of hepatitis C virus (PPR = 8.1, 95% CI: 6.4, 10.4), and 2 times the prevalence of hepatitis B virus (PPR = 2.0, 95% CI: 1.5, 2.7) compared with noninjecting prisoner populations. Among these articles, only those from Iran, Scotland, Spain, and Italy included the availability of methadone therapy; 2 articles included information on access to needle exchange programs by PWID detainees. HIV prevalence was more than 2 times higher among SW (PPR = 2.6, 95% CI: 2.2, 3.1) and 5 times higher among MSM (PPR = 5.3, 95% CI: 3.5, 7.9) compared with other prisoners. None of these articles reported HIV prevention coverage among SW or transgender women; 1 described HIV and sexually transmitted infection screening for MSM in prison. Prevention programs specific to key populations are important, particularly for populations that are criminalized and/or may cycle in and out of prison.
| S-EPMC5982732 | biostudies-literature
Project description:BackgroundPublic health measures designed to reduce SARS-CoV-2 transmission led to reduced access to care and prevention services for people living with or at risk of acquiring HIV, particularly during the initial introduction of extensive restrictions. This reduction in access may have contributed to increases in HIV transmission not outweighed by decreases in transmission occurring as a result of reduced contact rates promoted by the same public health measures.MethodsWe synthesize available province-wide HIV data in British Columbia, Canada, together with public mobility data to phylogenetically investigate the early impacts of SARS-CoV-2 on HIV transmission. Cluster growth, coalescent branching events and lineage-level diversification rates were assessed in "pre-lockdown" (January 22-March 21, 2020), "lockdown" (March 22-May 20, 2020) and "post-lockdown" (May 21-July 19, 2020) to facilitate comparison of transmission trends across key populations.FindingsResults reveal increased HIV transmission in a limited number of clusters in association with reduced access to health services during the initial introduction of SARS-CoV-2-related restrictions. In particular, clusters associated with people who inject drugs (PWID) show rapid growth, extensive branching events in phylogenetic trees during and following the lockdown period, and elevated median change in individuals' viral diversification rates during lockdown compared to clusters associated with men who have sex with men (MSM), consistent with increased transmission rates between PWID.InterpretationIncreased vigilance and innovative targeted solutions are critical to offset potential negative impacts of SARS-CoV-2 or future pandemic-related restrictions on HIV epidemic dynamics.FundingFunding sources include Genome Canada and Genome BC, the Public Health Agency of Canada, the BC Centre for Excellence in HIV/AIDS, and the Canadian Institutes of Health Research Coronavirus Rapid Response Programme. Student funding includes a NSERC CREATE scholarship and a Canadian Institutes of Health Research graduate fellowship.
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Project description:BackgroundAssessing patterns and trends in new infections is key to better understanding of HIV epidemics, and is best done through monitoring changes in incidence over time. In this study, we examined disparities in geographical trends of HIV epidemics among people who inject drugs (PWIDs), female sex workers (FSWs) and hijra/transgender/male sex workers (H/MSWs), in Pakistan.MethodsThe UNAIDS Estimation and Projection Package (EPP) mathematical model was used to explore geographical trends in HIV epidemics. Four rounds of mapping and surveillance data collected among key populations (KPs) across 20 cities in Pakistan between 2005-2011 was used for modeling. Empirical estimates of HIV prevalence of each KP in each city were used to fit the model to estimate prevalence and incidence over time.ResultsHIV incidence among PWIDs in Pakistan reached its peak in 2011, estimated at 45.3 per 1000 person-years. Incidence was projected to continue to rise from 18.9 in 2015 to 24.3 in 2020 among H/MSWs and from 3.2 in 2015 to 6.3 in 2020 among FSWs. The number of people living with HIV in Pakistan was estimated to steadily increase through at least 2020. HIV incidence peak among PWIDs ranged from 16.2 in 1997 in Quetta to 71.0 in 2010 in Faisalabad (per 1000 person-years). Incidence among H/MSWs may continue to rise through 2020 in all the cities, except in Larkana where it peaked in the early 2000s. In 2015, model estimated incidence among FSWs was 8.1 in Karachi, 6.6 in Larkana, 2.0 in Sukkur and 1.2 in Lahore (per 1000 person-years).ConclusionsThere exists significant geographical heterogeneity in patterns and trends of HIV sub-epidemics in Pakistan. Focused interventions and service delivery approaches, different by KP and city, are recommended.
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Project description:IntroductionHIV prevention strategies often include outreach to female sex workers at social venues identified as places where people meet new sexual partners. Patrons and staff at these venues may include female sex workers, their clients, as well as others who have high rates of new sexual partnerships. Few studies have compared HIV/STI among venue-based and general populations, across types of venues, or by sub-group of the venue population. Program planners often assume that the prevalence of infection is highest among female sex workers and considerably lower among other people at these venues, but there are few empiric studies assessing the prevalence of infection by sex worker status and type of venue.MethodsIn 2011, we used the PLACE method to identify public venues where people meet new sexual partners across Jamaica. The study team visited all venues with reported sex work as well as a 10% random sample of other venues and subsequently interviewed and tested a probability sample of 991 venue patrons and workers for HIV and other STI.ResultsCommunity informants identified 1207 venues. All venues where sex work was reported (735 venues) and a random sample of the remainder (134 of 472) were selected for onsite visits. Of these, 585 were found and operational. At a stratified random sample of venues, survey teams interviewed and tested 717 women and 274 men. 394 women reported recent sex work and 211 of these women reported soliciting clients on the street. Women exchanging sex for money were more likely to be infected with HIV (5.4% vs 1.0%; OR = 5.6, 95% CI = 1.8,17.3) or syphilis (11.7% vs. 5.8%, OR = 2.2, 95% CI = 1.7,4,0) than other women, but not significantly more likely to be infected with gonorrhea (8.4% vs 7.8%; OR = 1.1,95% CI = 0.6,1.9), chlamydia (16.2% vs 21.6%;OR = 0.7,95% CI = 0.5,1.0) or trichomoniasis (23.0% vs 17.0%, OR = 1.5,95% CI = 0.9,2.2). Women at venues were more likely to report sex work and multiple partners than women interviewed in a 2008 national population-based household survey commissioned by the Ministry of Health.ConclusionsIn Jamaica, although the highest HIV prevalence was among street-based sex workers, the risk of HIV and STI extends to men and women at high risk venues, even those who do not self-identify as sex workers. Findings confirm the appropriateness of outreach to all men and women at these venues.
| S-EPMC6261031 | biostudies-literature
Project description:We present the Progression and Transmission of HIV (PATH 4.0), a simulation tool for analyses of cluster detection and intervention strategies. Molecular clusters are groups of HIV infections that are genetically similar, indicating rapid HIV transmission where HIV prevention resources are needed to improve health outcomes and prevent new infections. PATH 4.0 was constructed using a newly developed agent-based evolving network modeling (ABENM) technique and evolving contact network algorithm (ECNA) for generating scale-free networks. ABENM and ECNA were developed to facilitate simulation of transmission networks for low-prevalence diseases, such as HIV, which creates computational challenges for current network simulation techniques. Simulating transmission networks is essential for studying network dynamics, including clusters. We validated PATH 4.0 by comparing simulated projections of HIV diagnoses with estimates from the National HIV Surveillance System (NHSS) for 2010-2017. We also applied a cluster generation algorithm to PATH 4.0 to estimate cluster features, including the distribution of persons with diagnosed HIV infection by cluster status and size and the size distribution of clusters. Simulated features matched well with NHSS estimates, which used molecular methods to detect clusters among HIV nucleotide sequences of persons with HIV diagnosed during 2015-2017. Cluster detection and response is a component of the U.S. Ending the HIV Epidemic strategy. While surveillance is critical for detecting clusters, a model in conjunction with surveillance can allow us to refine cluster detection methods, understand factors associated with cluster growth, and assess interventions to inform effective response strategies. As surveillance data are only available for cases that are diagnosed and reported, a model is a critical tool to understand the true size of clusters and assess key questions, such as the relative contributions of clusters to onward transmissions. We believe PATH 4.0 is the first modeling tool available to assess cluster detection and response at the national-level and could help inform the national strategic plan.
| S-EPMC8162476 | biostudies-literature
Project description:IntroductionPrevention of mother-to-child HIV transmission (PMTCT) strategies include combined short-course antiretrovirals during pregnancy (Option A), triple-drug antiretroviral treament (ART) during pregnancy and breastfeeding (Option B), or lifelong ART (Option B+). The WHO also recommends ART for HIV treatment and prevention of sexual transmission of HIV. The impact of PMTCT strategies on prevention of sexual HIV transmission of HIV is not known. We estimated the population-level impact of PMTCT interventions on heterosexual HIV transmission in southwestern Uganda and KwaZulu-Natal, South Africa, two regions with different HIV prevalence and fertility rates.Materials and methodsWe constructed and validated dynamic, stochastic, network-based HIV transmission models for each region. PMTCT Options A, B, and B+ were simulated over ten years under three scenarios: 1) current ART and PMTCT coverage, 2) current ART and high PMTCT coverage, and 3) high ART and PMTCT coverage. We compared adult HIV incidence after ten years of each intervention to Option A (and current ART) at current coverage.ResultsAt current coverage, Options B and B+ reduced heterosexual HIV incidence by about 5% and 15%, respectively, in both countries. With current ART and high PMTCT coverage, Option B+ reduced HIV incidence by 35% in Uganda and 19% in South Africa, while Option B had smaller, but meaningful, reductions. The greatest reductions in HIV incidence were achieved with high ART and PMTCT coverage. In this scenario, all PMTCT strategies yielded similar results.DiscussionImplementation of Options B/B+ reduces adult HIV incidence, with greater effect (relative to Option A at current levels) in Uganda than South Africa. These results are likely driven by Uganda's higher fertility rates.
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