A multi-state Markov model using notification data to estimate HIV incidence, number of undiagnosed individuals living with HIV, and delay between infection and diagnosis: Illustration in France, 2008–2018

2021 ◽  
pp. 096228022110326
Author(s):  
Charlotte Castel ◽  
Cecile Sommen ◽  
Yann Le Strat ◽  
Ahmadou Alioum

Thirty-five years since the discovery of the human immunodeficiency virus (HIV), the epidemic is still ongoing in France. To guide HIV prevention strategies and monitor their impact, it is essential to understand the dynamics of the HIV epidemic. The indicator for reporting the progress of new infections is the HIV incidence. Given that HIV is mainly transmitted by undiagnosed individuals and that earlier treatment leads to less HIV transmission, it is essential to know the number of infected people unaware of their HIV-positive status as well as the time between infection and diagnosis. Our approach is based on a non-homogeneous multi-state Markov model describing the progression of the HIV disease. We propose a penalized likelihood approach to estimate the HIV incidence curve as well as the diagnosis rates. The HIV incidence curve was approximated using cubic M-splines, while an approximation of the cross-validation criterion was used to estimate the smoothing parameter. In a simulation study, we evaluate the performance of the model for reconstructing the HIV incidence curve and diagnosis rates. The method is illustrated in the population of men who have sex with men using HIV surveillance data collected by the French Institute for Public Health Surveillance since 2004.

Sexual Health ◽  
2007 ◽  
Vol 4 (1) ◽  
pp. 31 ◽  
Author(s):  
Samitha Ginige ◽  
Marcus Y. Chen ◽  
Jane S. Hocking ◽  
Andrew E. Grulich ◽  
Christopher K. Fairley

Background: To describe the changes in notification rates for HIV, as a proportion of people living with HIV infection, in Australia. Methods: Notification data on HIV and AIDS-related deaths published by the National Centre in HIV Epidemiology and Clinical Research were obtained and analysed for the period of 1988–2004. Results: The annual HIV notification rate per 100 people living with HIV fell significantly between 1988 and 1999 for all HIV cases and for men who have sex with men (MSM) specifically (P < 0.01). However, although there was an increase in HIV notifications between 2000 and 2004 (P = 0.01 for all HIV cases and P = 0.06 for MSM), the notification rate per 100 people living with HIV remained relatively stable (P = 0.6 for all HIV cases and P = 0.4 for MSM). Conclusions: These data suggest that despite significant rises in notifications for HIV, the effective reproductive rate for HIV has remained relatively stable since 1999.


2017 ◽  
Author(s):  
Wei Luo ◽  
David A Katz ◽  
Deven T Hamilton ◽  
Jennie McKenney ◽  
Samuel M Jenness ◽  
...  

BACKGROUND In the United States HIV epidemic, men who have sex with men (MSM) remain the most profoundly affected group. Prevention science is increasingly being organized around HIV testing as a launch point into an HIV prevention continuum for MSM who are not living with HIV and into an HIV care continuum for MSM who are living with HIV. An increasing HIV testing frequency among MSM might decrease future HIV infections by linking men who are living with HIV to antiretroviral care, resulting in viral suppression. Distributing HIV self-test (HIVST) kits is a strategy aimed at increasing HIV testing. Our previous modeling work suggests that the impact of HIV self-tests on transmission dynamics will depend not only on the frequency of tests and testers’ behaviors but also on the epidemiological and testing characteristics of the population. OBJECTIVE The objective of our study was to develop an agent-based model to inform public health strategies for promoting safe and effective HIV self-tests to decrease the HIV incidence among MSM in Atlanta, GA, and Seattle, WA, cities representing profoundly different epidemiological settings. METHODS We adapted and extended a network- and agent-based stochastic simulation model of HIV transmission dynamics that was developed and parameterized to investigate racial disparities in HIV prevalence among MSM in Atlanta. The extension comprised several activities: adding a new set of model parameters for Seattle MSM; adding new parameters for tester types (ie, regular, risk-based, opportunistic-only, or never testers); adding parameters for simplified pre-exposure prophylaxis uptake following negative results for HIV tests; and developing a conceptual framework for the ways in which the provision of HIV self-tests might change testing behaviors. We derived city-specific parameters from previous cohort and cross-sectional studies on MSM in Atlanta and Seattle. Each simulated population comprised 10,000 MSM and targeted HIV prevalences are equivalent to 28% and 11% in Atlanta and Seattle, respectively. RESULTS Previous studies provided sufficient data to estimate the model parameters representing nuanced HIV testing patterns and HIV self-test distribution. We calibrated the models to simulate the epidemics representing Atlanta and Seattle, including matching the expected stable HIV prevalence. The revised model facilitated the estimation of changes in 10-year HIV incidence based on counterfactual scenarios of HIV self-test distribution strategies and their impact on testing behaviors. CONCLUSIONS We demonstrated that the extension of an existing agent-based HIV transmission model was sufficient to simulate the HIV epidemics among MSM in Atlanta and Seattle, to accommodate a more nuanced depiction of HIV testing behaviors than previous models, and to serve as a platform to investigate how HIV self-tests might impact testing and HIV transmission patterns among MSM in Atlanta and Seattle. In our future studies, we will use the model to test how different HIV self-test distribution strategies might affect HIV incidence among MSM.


Author(s):  
Violeta J. Rodriguez ◽  
Andrew Spence ◽  
Mallory Monda ◽  
JoNell Potter ◽  
Deborah Jones

Background: Desires to have children are not lessened by a woman’s HIV status. Couples may lack information to conceive safely, and men may be especially uninformed. This study examined reproductive intentions, practices, and attitudes among men in HIV-infected couples, including attitudes regarding the perceived risk of vertical and horizontal transmission, safer conception, and preconception planning. Methods: Men ( n = 12) in HIV-infected couples were interviewed regarding reproductive intentions, attitudes, and knowledge and qualitative assessments were coded for dominant themes. Results: Themes primarily addressed concerns about the health of the baby, men’s involvement in pregnancy, safer conception, concerns about HIV transmission and antiretroviral therapy, and HIV infection. Men lacked information on safer conception and newer HIV prevention strategies, such as pre-exposure prophylaxis (PrEP). Discussion: Gaps in knowledge regarding preconception practices among men in HIV-infected couples were identified. Results highlight men’s desire for involvement in preconception planning, and opportunities for providers to facilitate this practice and to increase patient education and the use of PrEP are discussed.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S833-S833
Author(s):  
Alyson L Singleton ◽  
Brandon D Marshall ◽  
Xiao Zang ◽  
Amy S Nunn ◽  
William C Goedel

Abstract Background Although there is ongoing debate over the need for substantial increases in PrEP use when antiretroviral treatment confers the dual benefits of reducing HIV-related morbidity and mortality and the risk of HIV transmission, no studies to date have quantified the potential added benefits of PrEP use in settings with high treatment engagement across variable sub-epidemics in the United States. Methods We used a previously published agent-based network model to simulate HIV transmission in a dynamic network of 17,440 Black/African American and White MSM in Atlanta, Georgia from 2015 to 2024 to understand how the magnitude of reductions in HIV incidence attributable to varying levels of PrEP use (0–90%) changes in potential futures where high levels of treatment engagement (i.e. the UNAIDS ‘90-90-90’ goals and eventual ‘95-95-95’ goals) are achieved and maintained, as compared to current levels of treatment engagement in Atlanta (Figure 1). Model inputs related to HIV treatment engagement among Black/African American and White men who have sex with men in Atlanta. A comparison of current levels of treatment engagement (Panel A) to treatment engagement at ‘90-90-90’ (Panel B) and ‘95-95-95’ goals (Panel C). Results Even at achievement and maintenance of ‘90-90-90’ goals, 75% PrEP coverage reduced incidence rates by an additional 67.9% and 74.2% to 1.53 (SI: 1.39, 1.70) and 0.355 (SI: 0.316, 0.391) per 100 person-years for Black/African American and White MSM, respectively (Figure 2), compared to the same scenario with no PrEP use. Additionally, an increase from 15% PrEP coverage to 75% under ‘90-90-90’ goals only increased person-years of PrEP use per HIV infection averted, a measure of efficiency of PrEP, by 8.1% and 10.5% to 26.7 (SI: 25.6, 28.0) and 73.3 (SI: 70.6, 75.7) among Black/African American MSM and White MSM, respectively (Figure 3). Overall (Panel A) and race-stratified (Panel B and Panel C) marginal changes in HIV incidence over ten years among Black/African American and White men who have sex with men in Atlanta across scenarios of varied levels of treatment engagement among agents living with HIV infection and levels of pre-exposure prophylaxis use among HIV-uninfected agents. Note: All changes are calculated within each set of treatment scenarios relative to a scenario where no agents use pre-exposure prophylaxis. Person-years of pre-exposure prophylaxis use per HIV infection averted among Black/African American (Panel A) and White (Panel B) men who have sex with men in Atlanta across scenarios of varied levels of treatment engagement among agents living with HIV infection and levels of pre-exposure prophylaxis use among HIV-uninfected agents. Note: The number of HIV infections averted is calculated within each set of treatment scenarios relative to a scenario where no agents use pre-exposure prophylaxis. Conclusion Even in the context of high treatment engagement, substantial expansion of PrEP use still contributes to meaningful decreases in HIV incidence among MSM with minimal changes in person-years of PrEP use per HIV infection averted, particularly for Black/African American MSM. Disclosures All Authors: No reported disclosures


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S461-S461
Author(s):  
Meredith E Clement ◽  
Rick Zimmerman ◽  
Josh Grimm ◽  
Joseph Schwartz

Abstract Background The “Undetectable = Untransmittable” (“U=U”) campaign is gaining traction, but prior studies from 2012–2017 have shown that the proportion of gay and bisexual men who have sex with men (GBMSM) who are aware of or have perceived accuracy of U=U is low. We report findings from a survey administered to GBMSM in 2018 to understand whether the landscape is changing with respect to U=U message dissemination. Methods GBMSM were recruited on gay dating apps to complete a 96 question survey. Survey data were collected in April-August of 2018. Collected data elements included demographic information, HIV status, ART and PrEP use, and beliefs and opinions regarding HIV transmission. Results 969 GBMSM completed the survey; of whom, 678 had analyzable data (241 had never had anal sex with a man and 54 were missing ≥1 of the variables used in the analysis). Average age was 43 years, 65% were white, 15% black, 15% white, and 15% were HIV-infected (of whom 92% were on anti-retrovirals). Of the 85% who were HIV-uninfected, 39% were on PrEP. In response to the statement that a person with an undetectable viral load cannot transmit HIV to an HIV-uninfected person, 24% strongly agreed. Among HIV-negative GBMSM, 33% of those on PrEP agreed and 12% of those not on PrEP agreed. Among those living with HIV, 42% agreed. A multivariable logistic regression was run to explain correlates of strong agreement with U=U, using the following variables: age, education, being Black, being Hispanic, relationship status, number of lifetime male sexual partners, condom use with most recent anal sex, HIV status, PrEP use, and attitudes about living with HIV. Variables associated with strong agreement with U=U were living with HIV (AOR = 1.63, P < 0.001), taking PrEP (AOR = 2.85, P < 0.001), most recent encounter’s condom use (AOR = 2.22, P = 0.003), and having positive attitudes about living with HIV (AOR= 1.93, P < 0.001). Table 1 shows percentages for each of these variables (bivariate relationships) strongly agreeing with U=U. Conclusion Now that U=U has been scientifically proven, the challenge is public awareness. U=U awareness seems to be improving among GBMSM, with HIV-negative GBMSM making the greatest strides. Education around U=U and PrEP efficacy may help reduce guilt around HIV transmission and alleviate HIV stigma. Disclosures All authors: No reported disclosures.


Sexual Health ◽  
2017 ◽  
Vol 14 (1) ◽  
pp. 51 ◽  
Author(s):  
Veronica C. Lee ◽  
Patrick S. Sullivan ◽  
Stefan D. Baral

Infectious disease epidemics occur within dynamic systems and environments that shape risk and, ultimately, the spread of infectious diseases. Gay men and other men who have sex with men (MSM) are disproportionately impacted by HIV everywhere in the world. Several emerging trends present risks for sustained or increased HIV acquisition and transmission, and the growth of global travel in the context of emerging online platforms for social/sexual networking is discussed here. Four factors associated with travel that could potentiate HIV transmission are highlighted: different patterns of sexual risk behaviours during travel; the growth of online tools to meet sex partners more efficiently; the global heterogeneity of HIV strains; and the potential for diassortative mixing of men from high- and low-HIV prevalence areas. Prevention tools and services must rise to these challenges, and innovative mobile applications and programs have played, and will continue to play, an important role in supporting MSM at risk for or living with HIV during their periods of travel.


Sexual Health ◽  
2016 ◽  
Vol 13 (4) ◽  
pp. 373 ◽  
Author(s):  
Wei Zhang ◽  
Jun-Jie Xu ◽  
Huachun Zou ◽  
Jing Zhang ◽  
Ning Wang ◽  
...  

Background: The national annually reported proportion of men who have sex with men (MSM) among people living with HIV (PLWH) is growing in China. To better inform the public health sector how to improve HIV prevention strategies, it is necessary to understand the current level of HIV incidence and its correlates. Methods: Google Scholar, PubMed, Web of Science and three major Chinese electronic publication databases (http://qikan.cqvip.com/, http://g.wanfangdata.com.cn/, http://www.cnki.net/, respectively) were searched for studies reporting HIV incidence. Comprehensive Meta-Analysis (CMA) 2.0 statistical software (Biostat, Inc. Englewood, NJ, USA) was used to calculate the pooled HIV incidence and perform subgroup-analysis to find correlates for HIV seroconversion in Chinese MSM. Random effects modelling was then conducted. Results: Twenty-five eligible studies were included in this meta-analysis. The calculated pooled HIV incidence was 5.61/100 person years (PY), with an increasing trend over time (3.24/100PY, 5.29/100PY, 5.50/100PY in 2005–2008, 2009–2011, 2012–2014 respectively, χ2 test for trend P = 0.04). Subgroup analyses indicated that age <25 years (rate ratio (RR) = 1.85), junior college education and below (RR = 1.87), having ≥ 2 male sexual partners in past 6 months (RR = 2.50), baseline syphilis infection (RR = 2.99), homosexual orientation (RR = 1.91), preferred bottom/versatile roles in anal sexual intercourse (RR = 2.33), and having unprotected anal intercourse in the past 6 months (RR = 2.16) significantly increased the risk for HIV seroconversion (each P < 0.05). Uncircumcised MSM had a marginal statistically significant higher HIV incidence (RR = 3.35, P = 0.051). Conclusion: HIV incidence is still alarmingly high among Chinese MSM. Stronger HIV intervention strategies should be implemented, in particular targeting young, less educated and syphilis-infected MSM.


2020 ◽  
Author(s):  
Linwei Wang ◽  
Nasheed Moqueet ◽  
Anna Simkin ◽  
Jesse Knight ◽  
Huiting Ma ◽  
...  

ABSTRACTBackgroundHIV pre-exposure prophylaxis (PrEP) may change serosorting patterns. We examined the influence of serosorting on the population-level HIV transmission impact of PrEP, and how impact could change if PrEP users stopped serosorting.MethodsWe developed a compartmental HIV transmission model parameterized with bio-behavioural and HIV surveillance data among men who have sex with men in Canada. We separately fit the model with serosorting and without serosorting (random partner-selection proportional to availability by HIV-status (sero-proportionate)), and reproduced stable HIV epidemics (2013-2018) with HIV-prevalence 10.3%-24.8%, undiagnosed fraction 4.9%-15.8%, and treatment coverage 82.5%-88.4%. We simulated PrEP-intervention reaching stable coverage by year-1 and compared absolute difference in relative HIV-incidence reduction 10-year post-intervention (PrEP-impact) between: models with serosorting vs. sero-proportionate mixing; and scenarios in which PrEP users stopped vs. continued serosorting. We examined sensitivity of results to PrEP-effectiveness (44%-99%) and coverage (10%-50%).FindingsModels with serosorting predicted a larger PrEP-impact compared with models with sero-proportionate mixing under all PrEP-effectiveness and coverage assumptions (median (inter-quartile-range): 8.1%(5.5%-11.6%)). PrEP users” stopping serosorting reduced PrEP-impact compared with when PrEP users continued serosorting: reductions in PrEP-impact were minimal (2.1%(1.4%-3.4%)) under high PrEP-effectiveness (86%-99%); however, could be considerable (10.9%(8.2%-14.1%)) under low PrEP effectiveness (44%) and high coverage (30%-50%).InterpretationModels assuming sero-proportionate mixing may underestimate population-level HIV-incidence reductions due to PrEP. PrEP-mediated changes in serosorting could lead to programmatically-important reductions in PrEP-impact under low PrEP-effectiveness (e.g. poor adherence/retention). Our findings suggest the need to monitor sexual mixing patterns to inform PrEP implementation and evaluation.FundingCanadian Institutes of Health ResearchRESEARCH IN CONTEXTEvidence before this studyWe searched PubMed for full-text journal articles published between Jan 1, 2010, and Dec 31, 2017, using the MeSH terms “pre-exposure prophylaxis (PrEP)” and “homosexuality, male” and using key words (“pre-exposure prophylaxis” or “preexposure prophylaxis” or “PrEP”) and (“men who have sex with men” or “MSM”) in titles and abstracts. Search results (520 records) were reviewed to identify publications which examined the population-level HIV transmission impact or population-level cost-effectiveness of PrEP in high-income settings. We identified a total of 18 modelling studies of PrEP impact among men who have sex with men (MSM) and four studies were based on the same model with minor variations (thus only the most recent one was included). Among the 15 unique models of PrEP impact, three included serosorting. A total of nine models have assessed the individual-level behaviour change among those on PrEP and its influence on the transmission impact of PrEP. Specifically, the models examined increases in number of partners and reductions in condom use. Most models predicted that realistic increases in partner number or decreases in condom use would not fully offset, but could weaken, PrEP”s impact on reducing HIV transmission. We did not identify any study that examined the influence of serosorting patterns on the estimated transmission impact of PrEP at the population-level, or what could happen to HIV incidence if the use of PrEP changes serosorting patterns.Added value of this studyWe used a mathematical model of HIV transmission to estimate the influence of serosorting and PrEP-mediated changes in serosorting on the transmission impact of PrEP at the population-level among MSM. We found the impact of PrEP was higher under epidemics with serosorting, compared with comparable epidemics simulated assuming sero-proportionate mixing. Under epidemics with serosorting, when PrEP users stopped serosorting (while other men continue to serosort among themselves) we found a reduced PrEP impact compared with scenarios when PrEP users continued to serosort. The magnitude of reduction in PrEP impact was minimal if PrEP-effectiveness was high; however, could be programmatically-meaningful in the context of low PrEP-effectiveness (e.g., poor adherence or retention) and high PrEP coverage. To our knowledge, our study is the first to directly examine the influence of serosorting and PrEP-mediated changes in serosorting on the transmission impact of PrEP and its underlying mechanism.Implications of all the available evidenceOur findings suggest that models which do not consider baseline patterns of serosorting among MSM could potentially underestimate PrEP impact. In addition to monitoring individual-level behavioural change such as condom use, our findings highlight the need to monitor population-level sexual mixing patterns and their changes over time among MSM in the design and evaluation of PrEP implementation.


BMJ Open ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. e018533 ◽  
Author(s):  
Juliana Maria Reyes-Urueña ◽  
Colin N J Campbell ◽  
Núria Vives ◽  
Anna Esteve ◽  
Juan Ambrosioni ◽  
...  

ObjectiveUndiagnosed HIV continues to be a hindrance to efforts aimed at reducing incidence of HIV. The objective of this study was to provide an estimate of the HIV undiagnosed population in Catalonia and compare the HIV care cascade with this step included between high-risk populations.MethodsTo estimate HIV incidence, time between infection and diagnosis and the undiagnosed population stratified by CD4 count, we used the ECDC HIV Modelling Tool V.1.2.2. This model uses data on new HIV and AIDS diagnoses from the Catalan HIV/AIDS surveillance system from 2001 to 2013. Data used to estimate the proportion of people enrolled, on ART and virally suppressed in the HIV care cascade were derived from the PISCIS cohort.ResultsThe total number of people living with HIV (PLHIV) in Catalonia in 2013 was 34 729 (32 740 to 36 827), with 12.3% (11.8 to 18.1) of whom were undiagnosed. By 2013, there were 8458 (8101 to 9079) Spanish-born men who have sex with men (MSM) and 2538 (2334 to 2918) migrant MSM living with HIV in Catalonia. A greater proportion of migrant MSM than local MSM was undiagnosed (32% vs 22%). In the subsequent steps of the HIV care cascade, migrants MSM experience greater losses than the Spanish-born MSM: in retention in care (74% vs 55%), in the proportion on combination antiretroviral treatment (70% vs 50%) and virally suppressed (65% vs 46%).ConclusionsBy the end of 2013, there were an estimated 34 729 PLHIV in Catalonia, of whom 4271 were still undiagnosed. This study shows that the Catalan epidemic of HIV has continued to expand with the key group sustaining HIV transmission being MSM living with undiagnosed HIV.


2016 ◽  
Vol 132 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Ethan Morgan ◽  
Alexandra M. Oster ◽  
Stephanie Townsell ◽  
Donna Peace ◽  
Nanette Benbow ◽  
...  

Objective: Analysis of HIV nucleotide sequences can be used to identify people with highly similar HIV strains and understand transmission patterns. The objective of this study was to identify groups of people highly connected by HIV transmission and the extent to which transmission occurred within and between geographic areas in Chicago, Illinois. Methods: We analyzed genetic sequences in the HIV-1 pol region in samples collected from people participating in the VARHS program in Chicago during 2005-2011. We determined pairwise genetic distance, inferred potential transmission events between HIV-infected people whose sequences were ≤1.5% genetically distant, and identified clusters of connected people. We used multivariable analysis to determine demographic characteristics and risk attributes associated with degree of connectivity. Results: Of 1154 sequences, 177 (15.3%) were tied to at least 1 other sequence. We determined that younger people, men, non-Hispanic black people, and men who have sex with men were more highly connected than other HIV-infected people. We also identified a high degree of geographic heterogeneity—48 of 67 clusters (71.6%) contained people from >1 Chicago region (north, south, or west sides). Conclusion: Our results indicate a need to address HIV transmission through the networks of younger non-Hispanic black men who have sex with men. The high level of geographic heterogeneity observed suggests that HIV prevention programs should be targeted toward networks of younger people rather than geographic areas of high incidence. This study could also guide prevention efforts in other diverse metropolitan regions with characteristics similar to those of Chicago.


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