Joseph Larmarange

Comparing modelled HIV incidence estimates with empirical HIV incidence observations in high-burden HIV African epidemic settings: systematic review and meta-regression

Joseph LARMARANGE — 2026-02-10T17:15:53Z

Authors

Oliver Stevens, Michelle Moffa, Joanne H. Hunt, Kyle Patel, Tihitna Aytenfisu, Adam Akullian, Rebecca L Anderson, Peter Bock, Amelia C Crampin, Sian Floyd, Simon Gregson, Richard J Hayes, Collins Iwuji, Ivan Kasamba, Daniel Kwaro, Joseph Larmarange, Shahin Lockman, Denna Michael, Louisa Moorhouse, Joseph Mugisha, Elphas Okango, Maya L Petersen, Victor Ssempijja, Emma Slaymaker, Frank Tanser, Cari van Schalkwyk, M. Kate Grabowski, Jeffrey W. Imai-Eaton

Abstract

Background

HIV incidence in sub-Saharan Africa has declined substantially since 2000 according to epidemic estimates published by UNAIDS. These estimates, derived by fitting mathematical models to national surveillance data, guide HIV programmes and epidemic response strategies. We assessed whether the level and age distribution of HIV incidence from modelled estimates were consistent with empirical HIV incidence observations, and whether incidence levels and trends were systematically different between study types, populations, and age groups.

Methods

We conducted an updated systematic review of adult HIV incidence data from sub-Saharan Africa published July 2019-February 2024 by searching Scopus, PubMed, Embase, and OVID databases, and combined with earlier systematic review data. We matched empirical incidence measurements between 1990-2023 to UNAIDS HIV incidence estimates by study area, sex, age group, and year. We used Bayesian mixed-effect Poisson regression to estimate (1) incidence rate ratios (IRR) between empirical observations and matched modelled incidence estimates adjusted for sex, year and study type/population; and (2) time trends in age-specific incidence from population-based cohort studies and household surveys.

Results

3560 HIV empirical incidence measurements were included from 179 studies conducted in 21 countries, comprising 23,000 new infections and 3.1 million person-years. Incidence observations from nationally-representative household surveys (IRR 1.07 95%CI 0.68, 1.67) and population-representative study populations (IRR 0.98 95%CI 0.51, 1.89) were not significantly different from matched modelled estimates, and declined at the same rate as modelled estimates (annual aRR 0.99 95%CI 0.98, 1.01). Studies among pregnant women (IRR 2.60 95%CI 1.58, 4.28), control arms of clinical trials (IRR 3.01 95%CI 1.90, 4.77) and key populations (FSW IRR: 6.46 95%CI 4.18, 10.00; MSM 44.02 95%CI 27.35, 70.87) had significantly higher incidence than modelled total population incidence estimates. Across population cohorts in Eastern and Southern Africa, HIV incidence among adults aged 15-49 declined by 75-90% between 2010-2023, and declined 7% (95%CI 4-10%) faster per year among young adults 15-24 compared to age 25+ years. Modelled incidence declined similarly to cohort data, but did not reflect the aging of the epidemic.

Conclusion

Observed incidence in population-representative studies in sub-Saharan Africa has declined steeply. Mathematical models that infer incidence from cross-sectional HIV surveillance data estimated the same incidence level and decline over time as population-representative studies. Studies with non-representative inclusion criteria had significantly higher incidence, including those among pregnant women and most HIV prevention/vaccine efficacy trials. The age pattern of incidence in modelled estimates should be reconsidered to capture the aging of the epidemic indicated by cohort studies.

Modélisation de l'impact épidémiologique potentiel du retrait du PEPFAR en Côte d'Ivoire, au Mali et au Sénégal

Joseph LARMARANGE — 2025-03-20T13:03:45Z

Responsables scientifiques

LARMARANGE Joseph, Ceped
NIANGORAN Serge, PAC-CI
SILHOL Romain, Imperial College London

Partenaires

Imperial College London https://www.imperial.ac.uk/
PAC-CI (programme ANRS de Côte d'Ivoire) https://web.pac-ci.org/
Université Mac Gill https://www.mcgill.ca/

Membres du projet

BOILY Marie-Claude, Imperial College London
LARMARANGE Joseph, IRD / Ceped
MAHEU-GIROUX Mathieu, McGill University
MIAN Anatole, PAC-CI
MOH Raoul, PAC-CI
NIANGORAN Serge, PAC-CI
SILHOL Romain, Imperial College London

Financement

ANRS|MIE

Résumé

La décision de la nouvelle administration américaine d'interrompre le financement du plan présidentiel d'urgence pour la lutte contre le Sida (PEPFAR), officiellement pour une durée minimale de 90 jours à partir du 20 Janvier 2025, pourrait avoir des effets dévastateurs sur les populations vivant en Afrique de l'Ouest. En effet, ces fonds apportaient une aide vitale, non seulement en finançant plus de la moitié de l'accès au diagnostic et traitement antirétroviral contre le VIH auprès des populations vivant avec le VIH (PVVIH), mais supportait également de nombreux programmes de prévention de l'infection VIH, notamment parmi les populations clés (i.e., les plus touchées par le VIH), comme les travailleuses du sexe (TS) et les hommes ayant des rapports sexuels avec d'autres hommes (HSH). Ces financements américains, conjugués aux efforts nationaux des pays d'Afrique de l'Ouest et de la communauté internationale, ont permis de diminuer de moitié le nombre de nouvelles infections et décès dus au VIH entre 2010 et 2023 dans la région.

Afin d'alerter l'opinion et les pouvoirs politiques et scientifiques, il est urgent de

Comprendre l'impact épidémiologique (nouvelles infections, décès) de l'interruption et ou/arrêt de ce support afin de plaider pour une reprise de l'aide américaine et/ou d'un support européen additionnel ;
Identifier les activités de prévention et de traitement du VIH dont le maintien doit être considéré comme une priorité afin de minimiser l'impact du retrait PEPFAR ;
Évaluer quelles populations pourraient être les plus affectées par ce retrait, en s'appuyant sur des données stratifiées par population clé, transmises par des programmes nationaux de lutte nationale contre le sida, ainsi que les organisations non-gouvernementales implémentant ces politiques sur le terrain.

Pour ce projet, nous proposons d'adapter et utiliser le modèle épidémiologique développé dans le projet ATLAS pour simuler le cours de l'épidémie VIH pour la période 1980-2040 (prenant d'abord pour hypothèse contrefactuelle un maintien des activités PEPFAR au cours du temps), comparé à des scenarios de diminution des niveaux de prévention, diagnostic et traitement du VIH au cours de 2025-2040, au sein de chaque pays. Ce modèle a été récemment calibré pour représenter les dynamiques de transmission et contrôle du VIH au cours du temps en Côte d'Ivoire, au Mali et au Sénégal séparément, afin de prédire les dynamiques futures les plus plausibles.

Mots-Clés

Lutte contre le VIH, Pepfar, politiques publiques, modélisations épidémiologiques

Pays

Côte d'Ivoire, Mali, Sénégal

Calendrier

2025

Building better HIV models : a framework for incorporating evidence on structural determinants and interventions to estimate their impacts on HIV epidemics

Joseph LARMARANGE — 2024-10-28T15:41:00Z

Poster presented at HIVR4P 2024, the 5th HIV Research for Prevention Conference, October 2024, Lima, Peru.

Building better HIV models: a framework for incorporating evidence on structural determinants and interventions to estimate their impacts on HIV epidemics

James Stannah , Jorge Luis Flores Anato , Michael Pickles , Joseph Larmarange , Kate M. Mitchell , Adelina Artenie , Kostyantyn Dumchev , Serge Niangoran , Lucy Platt , Fern Terris-Prestholt Terris-Prestholt , Amteshwar Singh , Jack Stone , Peter Vickerman , Andrew Phillips , Leigh F Johnson , Mathieu Maheu-Giroux , Marie-Claude Boily

HIVR4P 2024, the 5th HIV Research for Prevention Conference, Oct 2024, Lima, Peru

Poster de conférence

hal-04971981

Authors

James Stannah, Jorge Luis Flores Anato, Michael Pickles, Joseph Larmarange, Kate M. Mitchell, Adelina Artenie, Kostyantyn Dumchev, Serge Niangoran, Lucy Platt, Fern Terris-Prestholt Terris-Prestholt, Amteshwar Singh, Jack Stone, Peter Vickerman, Andrew Phillips, Leigh F Johnson, Mathieu Maheu-Giroux, Marie-Claude Boily

Abstract

BACKGROUND : Structural determinants (SDs) are social, economic, political, cultural, organizational, and environmental factors that shape HIV inequalities across individuals and populations. UNAIDS' 10-10-10 targets aim to reduce exposure to SDs including punitive regulations, violence, stigma, and discrimination. Evidence-based dynamic HIV transmission models can help quantify the population-level impacts of SDs and structural interventions to inform decision-making. We appraised previous representations of SDs in HIV models to develop a new framework that supports the modelling and analysis of SDs.

METHODS : We performed a scoping review of HIV transmission dynamic modelling studies that modelled SDs, published until August 28, 2023, using Ovid Embase and Medline databases. To develop our framework, we considered how models represented exposures to SDs (statically vs dynamically) and reproduced causal pathways to estimate impacts on HIV, and the data they used.

RESULTS : We found 17 HIV modelling studies of SDs and/or structural interventions including incarceration of people who inject drugs (n=5) or Black men (n=2), violence against women (n=3), HIV-stigma (n=1), and homelessness (n=1), among other less well-defined exposures (e.g., “positive and negative attitudes”). Eight studies modelled SDs dynamically using granular exposure histories (e.g., current, recent, non-recent) that captured variation in duration and intensity of exposure. SDs mostly influenced HIV indirectly through simple causal pathways with single intermediate variables (mediators) – largely sexual/injecting partner numbers (n=9), mixing patterns (n=8), or condom use (n=6). Effects of SDs were mostly informed by cross-sectional data. Only seven studies fitted to observed trends in SDs or their effects on mediators/HIV. Using this, we developed our framework (Figure).

CONCLUSIONS : The representation of SDs in models could be refined to improve projections of their impacts and interventions using our framework. Fundamentally, this requires better inputs : more longitudinal studies investigating heterogeneity in SDs and their causal effects. Methods, findings, and limitations should be transparently communicated.

From conceptualising to modelling structural determinants and interventions in HIV transmission dynamics models: a scoping review and methodological framework for evidence-based analyses

Joseph LARMARANGE — 2024-09-25T07:24:35Z

Authors

James Stannah, Jorge Luis Flores Anato, Michael Pickles, Joseph Larmarange, Kate M. Mitchell, Adelina Artenie, Kostyantyn Dumchev, Serge Niangoran, Lucy Platt, Fern Terris-Prestholt, Aditya Singh, Jack Stone, Peter Vickerman, Andrew Phillips, Leigh Johnson, Mathieu Maheu-Giroux & Marie-Claude Boily

Abstract

Background

Including structural determinants (e.g. criminalisation, stigma, inequitable gender norms) in dynamic HIV transmission models is important to help quantify their population-level impacts and guide implementation of effective interventions that reduce the burden of HIV and inequalities thereof. However, evidence-based modelling of structural determinants is challenging partly due to a limited understanding of their causal pathways and few empirical estimates of their effects on HIV acquisition and transmission.

Methods

We conducted a scoping review of dynamic HIV transmission modelling studies that evaluated the impacts of structural determinants, published up to August 28, 2023, using Ovid Embase and Medline online databases. We appraised studies on how models represented exposure to structural determinants and causal pathways. Building on this, we developed a new methodological framework and recommendations to support the incorporation of structural determinants in transmission dynamics models and their analyses. We discuss the data and analyses that could strengthen the evidence used to inform these models.

Results

We identified 17 HIV modelling studies that represented structural determinants and/or interventions, including incarceration of people who inject drugs (number of studies [n] = 5), violence against women (n = 3), HIV stigma (n = 1), and housing instability (n = 1), among others (n = 7). Most studies (n = 10) modelled exposures dynamically. Almost half (8/17 studies) represented multiple exposure histories (e.g. current, recent, non-recent exposure). Structural determinants were often assumed to influence HIV indirectly by influencing mediators such as contact patterns, condom use, and antiretroviral therapy use. However, causal pathways' assumptions were sometimes simple, with few mediators explicitly represented in the model, and largely based on cross-sectional associations. Although most studies calibrated models using HIV epidemiological data, less than half (7/17) also fitted or cross-validated to data on the prevalence, frequency, or effects of exposure to structural determinants.

Conclusions

Mathematical models can play a crucial role in elucidating the population-level impacts of structural determinants and interventions on HIV. We recommend the next generation of models reflect exposure to structural determinants dynamically and mechanistically, and reproduce the key causal pathways, based on longitudinal evidence of links between structural determinants, mediators, and HIV. This would improve the validity and usefulness of predictions of the impacts of structural determinants and interventions.

Cost-effectiveness analysis of community-led HIV self-testing among key populations in Côte d'Ivoire, Mali, and Senegal

Joseph LARMARANGE — 2024-07-21T15:55:00Z

Cost‐effectiveness analysis of community‐led HIV self‐testing among key populations in Côte d'Ivoire, Mali, and Senegal

Ingrid Jiayin Lu , Romain Silhol , Marc d'Elbée , Marie-Claude Boily , Nirali Soni , Odette Ky-Zerbo , Anthony Vautier , Arlette Simo Fotso , Kéba Badiane , Metogara Traoré , Fern Terris-Prestholt , Joseph Larmarange , Mathieu Maheu-Giroux

Journal of the International AIDS Society, 2024, 27 (7), pp.1-12. ⟨10.1002/jia2.26334⟩

Article dans une revue

hal-04660337

Authors

Ingrid Jiayin Lu, Romain Silhol, Marc d'Elbée, Marie-Claude Boily, Nirali Soni, Odette Ky-Zerbo, Anthony Vautier, Artlette Simo Fosto, Kéba Badiane, Metogara Traoré, Fern Terris-Prestholt, Joseph Larmarange, Mathieu Maheu-Giroux, for the ATLAS Team

Abstract

Introduction

HIV self-testing (HIVST) is a promising strategy to improve diagnosis coverage among key populations (KP). The ATLAS (Auto Test VIH, Libre d'Accéder à la connaissance de son Statut) programme implemented HIVST in three West African countries, distributing over 380,000 kits up between 2019 and 2021, focussing on community-led distribution by KP to their peers and subsequent secondary distribution to their partners and clients. We aim to evaluate the cost-effectiveness of community-led HIVST in Côte d'Ivoire, Mali and Senegal.

Methods

An HIV transmission dynamics model was adapted and calibrated to country-specific epidemiological data and used to predict the impact of HIVST. We considered the distribution of HIVST among two KP—female sex workers (FSW), and men who have sex with men (MSM)—and their sexual partners and clients. We compared the cost-effectiveness of two scenarios against a counterfactual without HIVST over a 20-year horizon (2019–2039). The ATLAS-only scenario mimicked the 2-year implemented ATLAS programme, whereas the ATLAS-scale-up scenario achieved 95% coverage of HIVST distribution among FSW and MSM by 2025 onwards. The primary outcome is the number of disability-adjusted life-years (DALY) averted. Scenarios were compared using incremental cost-effectiveness ratios (ICERs). Costing was performed using a healthcare provider's perspective. Costs were discounted at 4%, converted to $USD 2022 and estimated using a cost-function to accommodate economies of scale.

Results

The ATLAS-only scenario was highly cost-effective over 20 years, even at low willingness-to-pay thresholds. The median ICERs were $126 ($88–$210) per DALY averted in Côte d'Ivoire, $92 ($88–$210) in Mali and 27$ ($88–$210) in Senegal. Scaling-up the ATLAS programme would also be cost-effective, and substantial epidemiological impacts would be achieved. The ICERs for the scale-up scenario were $199 ($122–$338) per DALY averted in Côte d'Ivoire, $224 ($118–$415) in Mali and $61 ($18–$128) in Senegal.

Conclusions

Both the implemented and the potential scale-up of community-led HIVST programmes in West Africa, where KP are important to overall transmission dynamics, have the potential to be highly cost-effective, as compared to a scenario without HIVST. These findings support the scale-up of community-led HIVST to reach populations that otherwise may not access conventional testing services.

Potential population-level effects of HIV self-test distribution among key populations in Côte d'Ivoire, Mali, and Senegal : a mathematical modelling analysis

Joseph LARMARANGE — 2024-07-09T11:57:51Z

Authors

Romain Silhol, Mathieu Maheu-Giroux, Nirali Soni, Arlette Simo Fotso, Nicolas Rouveau, Anthony Vautier, Clémence Doumenc-Aïdara, Olivier Geoffroy, Kouassi Noel N'Guessan, Younoussa Sidibé, Odé Kanku Kabemba, Papa Alioune Gueye, Pauline Dama Ndeye, Christinah Mukandavire, Prof Peter Vickerman, Abdelaye Keita, Prof Cheikh Tidiane Ndour, Joseph Larmarange, Prof Marie-Claude Boily on behalf of theATLAS Team

Abstract

Background

During 2019–21, the AutoTest VIH, Libre d'accéder à la connaissance de son Statut (ATLAS) programme distributed around 380 000 HIV self-testing kits to key populations, including female sex workers, men who have sex with men, and their partners, in Côte d'Ivoire, Mali, and Senegal. We aimed to estimate the effects of the ATLAS programme and national scale-up of HIV self-test distribution on HIV diagnosis, HIV treatment coverage, HIV incidence, and HIV-related mortality.

Methods

We adapted a deterministic compartmental model of HIV transmission in Côte d'Ivoire, parameterised and fitted to country-specific demographic, behavioural, HIV epidemiological, and intervention data in Côte d'Ivoire, Mali, and Senegal separately during 1980–2020. We simulated dynamics of new HIV infections, HIV diagnoses, and HIV-related deaths within scenarios with and without HIV self-test distribution among key populations. Models were separately parameterised and fitted to country-specific sets of epidemiological and intervention outcomes (stratified by sex, risk, age group, and HIV status, if available) over time within a Bayesian framework. We estimated the effects on the absolute increase in the proportion of people with HIV diagnosed at the end of 2021 for the ATLAS-only scenario and at the end of 2028 and 2038 for the HIV self-testing scale-up scenario. We estimated cumulative numbers of additional HIV diagnoses and initiations of antiretroviral therapy and the proportion and absolute numbers of new HIV infections and HIV-related deaths averted during 2019–21 and 2019–28 for the ATLAS-only scenario and during 2019–28 and 2019–38 for the HIV self-testing scale-up scenario.

Findings

Our model estimated that ATLAS could have led to 700 (90% uncertainty interval [UI] 500–900) additional HIV diagnoses in Côte d'Ivoire, 500 (300–900) in Mali, and 300 (50–700) in Senegal during 2019–21, a 04 percentage point (90% UI 03–05) increase overall by the end of 2021. During 2019–28, ATLAS was estimated to avert 1900 (90% UI 1300–2700) new HIV infections and 600 (400–800) HIV-related deaths across the three countries, of which 386% (90% UI 318–483) of new infections and 701% (604–773) of HIV-related deaths would be among key populations. ATLAS would avert 15% (08–31) of all HIV-related deaths across the three countries during this period. Scaling up HIV self-testing would avert 162% (90% UI 100–231) of all new HIV infections during 2019–28 in Senegal, 53% (30–89) in Mali, and 16% (10–24) in Côte d'Ivoire. HIV self-testing scale-up among key populations was estimated to increase HIV diagnosis by the end of 2028 to 13 percentage points (90% UI 08–19) in Côte d'Ivoire, 106 percentage points (53–168) in Senegal, and 36 percentage points (20–64) in Mali.

Interpretation

Scaling up HIV self-test distribution among key populations in western Africa could attenuate disparities in access to HIV testing and reduce infections and deaths among key populations and their partners.

Funding

Unitaid, Solthis, the UK Medical Research Council Centre for Global Infectious Disease Analysis, the EU European & Developing Countries Clinical Trials Partnership programme, and the Wellcome Trust.

The impact of past HIV interventions and diagnosis gaps on new HIV acquisitions, transmissions, and HIV-related deaths in Côte d'Ivoire, Mali, and Senegal

Joseph LARMARANGE — 2024-07-02T17:54:28Z

The impact of past HIV interventions and diagnosis gaps on new HIV acquisitions, transmissions, and HIV-related deaths in Côte d'Ivoire, Mali, and Senegal

AIDS. Official journal of the international AIDS Society, 2024, ⟨10.1097/QAD.0000000000003974⟩

Article dans une revue

hal-04632874

Authors

Silhol Romain; Maheu-Giroux Mathieu; Soni Nirali; Simo Fotso Arlette; Rouveau Nicolas; Vautier Anthony; Doumenc-Aïdara Clémence; Geoffroy Olivier; N'guessan Kouassi Noel; Sidibé Younoussa; Kabemba Odé Kanku; Gueye Papa Alioune; Ndeye Pauline Dama; Mukandavire Christinah; Vickerman Peter; Keita Abdelaye; Ndour Cheikh Tidiane; Ehui Eboi; Larmarange Joseph; Boily Marie-Claude

Abstract

Objectives

To estimate the epidemiological impact of past HIV interventions and the magnitude and contribution of undiagnosed HIV among different risk groups on new HIV acquisitions in Côte d'Ivoire, Mali and Senegal.

Design

HIV transmission dynamic models among the overall population and key populations [female sex workers (FSW), their clients, and MSM].

Methods

Models were independently parameterized and calibrated for each set of country-specific demographic, behavioural, and epidemiological data. We estimated the fraction of new HIV infections over 2012–2021 averted by condom use and antiretroviral therapy (ART) uptake among key population and nonkey population, the direct and indirect contribution of specific groups to new infections [transmission population-attributable fraction (tPAF)] over 2012–2021 due to prevention gaps, and the distribution of undiagnosed PWH by risk group in January 2022 and their tPAF over 2022–2031.

Results

Condom use and ART may have averted 81–88% of new HIV infections over 2012–2021 across countries, mostly because of condom use by key population. The tPAF of all key populations combined over 2012–2021 varied between 27% (Côte d'Ivoire) and 79% (Senegal). Male key population (clients of FSW and MSM) contributed most to new infections (>60% in Mali and Senegal) owing to their higher HIV prevalence and larger prevention gaps. In 2022, men represented 56% of all PWH with an undiagnosed infection in Côte d'Ivoire (male key population = 15%), 46% in Mali (male key population = 23%), and 69% in Senegal (male key population = 55%). If HIV testing and ART initiation rates remain at current levels, 20% of new HIV infections could be due to undiagnosed key population PWH in Côte d'Ivoire over 2022–2031, 53% in Mali, and 65% in Senegal.

Conclusion

Substantial HIV diagnosis gaps remain in Western Africa, especially among male key population. Addressing these gaps is key to impacting the HIV epidemics in the region and achieving the goal of ending AIDS by 2030.

Assessing the potential population-level impacts of HIV self-testing distribution among key populations in Cote d'Ivoire, Mali, and Senegal: a mathematical modelling analysis

Joseph LARMARANGE — 2023-08-28T14:53:40Z

Authors

Romain Silhol, Mathieu Maheu-Giroux, Nirali Soni, Arlette Simo Fotso, Nicolas Rouveau, Anthony Vautier, Clémence Doumenc-Aidara, Olivier Geoffroy, Kouassi Noel N'Guessan, Younoussa Sidibe, Ode Kanku Kabemba, Papa Alioune Gueye, Christinah Mukandavire, Peter Vickerman, Abdelaye Keita, Cheikh Tidiane Ndour, Eboi Ehui, Joseph Larmarange, Marie-Claude Boily for the ATLAS Team

Abstract

Background: A third of people living with HIV (PLHIV) in Western Africa had an undiagnosed infection in 2020. In 2019-2021, the ATLAS programme has distributed a total of 380 000 HIV self-testing (HIVST) kits to key populations (KP) including female sex workers (FSW) and men who have sex with men (MSM), and their partners in Cote d'Ivoire, Mali and Senegal. We predicted the potential impact of ATLAS and of national HIVST scale-up strategies among KP.

Methods: A deterministic model of HIV transmission was calibrated to country-specific empirical HIV and intervention data over time. We simulated scenarios reflecting 1) the actual ATLAS HIVST distribution only over 2019-2021 ( 2% of all tests done in countries), and 2) ATLAS followed by a scale-up of HIVST distribution to KP (total of 570 000 kits distributed each year). Impacts on HIV diagnosis, new HIV infections and deaths were derived using counterfactual scenarios without HIVST.

Findings: ATLAS was predicted to substantially increase HIV diagnosis among KP by the end of 2021, especially among MSM in Mali (94.3 percentage point [pp] increase), and a 1.0pp increase overall. ATLAS might have averted a median of 706 new HIV infections among KP over 2019-2028 in the 3 countries combined, especially among MSM, and 1794 new HIV infections (0.4-3.3% of all new HIV infections across countries) and 591 HIV-related deaths overall. HIVST scale-up increased HIV diagnosis at the end of 2028 by around 8pp among FSW and 33pp among MSM in every country. Overall increases ranged from 1.0pp (Cote d'Ivoire) to 11.0pp (Senegal). HIVST scale-up may avert 3-5% of new HIV infections among FSW, 3-10% among FSW clients, and 20-28% among MSM across countries (and 2-16% overall), and avert 13-18% of HIV-related deaths among MSM over 2019-2028.

Interpretation: Scaling-up HIVST distribution among KP in Western Africa may substantially attenuate disparities in access to HIV testing and help reduce HIV infections and deaths among KP and their partners.

PrEP injectable dans les pays à ressources limitées, promesses et défis

Joseph LARMARANGE — 2023-04-27T14:17:37Z

PrEP injectable dans les pays à ressources limitées, promesses et défis

Joseph Larmarange

2023

Article de blog scientifique

ird-04083902

Une étude de modélisation publiée fin 2022 tente de répondre, pour le cas sud-africain, à deux questions : quels seraient les impacts de santé publique d'un programme de PrEP injectable par rapport à un programme de PrEP orale ? à quel coût de la PrEP injectable celle-ci serait-elle plus coût-efficace que la PrEP orale ?

24th International AIDS Conference @ Montreal

Joseph LARMARANGE — 2022-08-08T18:58:39Z

Oral communications and poster presented at the 24^th International AIDS Conference 2022 in Montreal.

List of communications

Larmarange Joseph (2022) “Self-Testing, Empowerment and Self-Care: perspectives from lessons learned in implementing HIV self-testing in West Africa” (communication orale (symposium SA019), presented at the 24th International AIDS Conference, Montreal. https://programme.aids2022.org/Programme/Session/107.

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Larmarange - 2022 - Self-Testing, Empowerment and Self-Care perspecti.pdf 1.8 MiB

Nouaman Marcellin, Coffie Patrick A, Plazy Mélanie, Becquet Valentine, Agoua Aline, Zébago Clémence, Dao Hervé, Larmarange Joseph, Eholié Serge and ANRS 12381 PRINCESSE study group (2022) “Prevalence and incidence of sexually transmitted infections in a cohort of female sex workers in San Pedro, Côte d'Ivoire (ANRS 12381 PRINCESSE)” (poster), presented at the 24th International AIDS Conference, Montreal. https://programme.aids2022.org/Abstract/Abstract/?abstractid=6713.

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Abstract: BACKGROUND: The ANRS 12381 PRINCESSE study is an interventional single-arm cohort. Participants recruitment started in November 2019. The study aimed to evaluate a comprehensive and community-based care offer among FSWs aged '¥ 18 years in the San Pedro area. METHODS: Care services included quarterly syndromic screening for STIs, as well as vaginal and anal swabs for the screening of chlamydia trachomatis (CT) and neisseria gonorrhoea (NG) by polymerase chain reaction (PCR) at M0, M12 and M24. At the same visits, identification of dysplasias and precancerous lesions of the cervix was performed by visual inspection after applying acetic acid and Lugol's iodine. STIs were managed according to the national algorithm. We describe (i) the characteristics of cervical lesions as well as the prevalence of STIs (syndromic and PCR) and associated symptoms and (ii) the incidence of syndromic STIs during follow-up. RESULTS: In November 2021, 372 FSWs were included. The median age was 29 years, 34% had never been to school, 56% were Ivorian, and the median duration of sex work was 2 years. At inclusion, 4.7% [95% confidence interval: 2.8-7.5] had cervical lesions with 3.5% leukoplakia and 2.2% haemorrhagic cervical junction zone. The prevalence of syndromic STIs was 17.2% [13.0-22.6]; associated clinical signs were vaginal discharge (13.7%), vaginal ulceration (2.1%), lower abdominal pain (4.3%) and cervical inflammation (2.6%). The prevalence of anovaginal CT and NG were 8.7% [6.2- 12.1] and 10.4% [7.6- 13.9], respectively; clinical signs were found in 2.4% of CT-positive and 12.2% of NG-positive FSWs. Most FSWs with syndromic STIs did not have CT or NG infection. During the follow-up, 82 cases of syndromic STIs were observed per 209 person-years, i.e. an incidence of 39.1% [31.1- 49.0]. PCR data at M12 and M24 are being consolidated and will allow estimating the incidence of CT and NG. CONCLUSIONS: A high prevalence and incidence of syndromic STIs were observed among FSWs, highlighting the importance and the interest of a regular follow-up. The results also showed the predominantly asymptomatic nature of STIs discovered by PCR in this at-risk population and, therefore, the importance of coupling syndromic screening and PCR analyses.

Nouaman et al. - 2022 - Prevalence and incidence of sexually transmitted i.pdf 832 KiB

Plazy Mélanie, Nouaman Marcellin, Becquet Valentine, Agoua Aline, Zébago Clémence, Dao Hervé, Coffie Patrick A, Eholié Serge, Larmarange Joseph and ANRS 12381 PRINCESSE study group (2022) “Delays to PrEP initiation among female sex workers in Côte d'Ivoire (ANRS 12381 PRINCESSE project)” (poster), presented at the 24th International AIDS Conference, Montreal. https://programme.aids2022.org/Abstract/Abstract/?abstractid=6824.

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Abstract: BACKGROUND: To describe the delays to initiation of oral pre-exposure prophylaxis (PrEP) among female sex workers (FSW) in Côte d''Ivoire. METHODS: The ANRS 12381 PRINCESSE project is a single-arm interventional cohort aiming to evaluate the implementation of a comprehensive and community-based care offer among FSW aged '¥18 years in the San Pedro region since end-2019, through a mobile clinic operating on 10 prostitution sites (visited every two weeks). PrEP is offered to all HIV-positive FSW after verifying the creatinine level (results valid for one month). We described the time between FSW's interest for PrEP and PrEP initiation (or end of follow-up) among HIV- and hepatitis B virus-negative (HBsAg-) FSW included until end-October 2021. The probability of PrEP initiation since PrEP interest is described through a Kaplan-Meier curve censored on end-November 2021 (an analysis censored at the date of the last visit was also conducted). RESULTS: Of the 362 FSW included in the PRINCESSE cohort, 302 were HIV-/AgHBs-, and for 296 of them, PrEP was presented by medical staff (95.2% at inclusion). In total, 292 FSW expressed PrEP interest, and 192 (65.8%) initiated PrEP: 18 on the same day (the biological test having been performed during a previous visit), 148 during the next visit (median time since interest: 3 weeks [Inter-Quartile Range: 2-6]) and 26 during a subsequent visit (median time: 20 weeks [9-36]). The probability of PrEP initiation after PrEP interest was 39.0% at 1 month and 56.6% at 3 months (censoring on the date of the last visit, these proportions were 50.7% and 74.6%, respectively). Among the 100 FSW who did not initiate PrEP despite expressing interest, 68 were never seen again in the project; 4 declared that they were no longer interested in PrEP (median time since interest: 12 weeks [10-19]), 1 was tested HIV+ (delay of 2 weeks), and 27 were seen >1 month later (their biological tests were no longer valid). CONCLUSIONS: Despite strong PrEP interest among FSW, PrEP initiation remained suboptimal. Barriers to PrEP initiation should be more explored and considered to find appropriate solutions to make PrEP effective among this specific key population.

Plazy et al. - 2022 - Delays to PrEP initiation among female sex workers.pdf 484.6 KiB

Silhol Romain, Maheu-Giroux Mathieu, Soni Nirali, Simo Fotso Arlette, Rouveau Nicolas, Vautier Anthony, Doumenc-Aïdara Clémence, N'Guessan Kouakou, Mukandavire Christinah, Vickerman Peter, Keita Abdelaye, Ndour Cheikh Tidiane, Larmarange Joseph, Boily Marie Claude and ATLAS Team (2022) “Identifying population-specific HIV diagnosis gaps in Western Africa and assessing their impact on new infections: a modelling analysis for Côte d'Ivoire, Mali and Senegal” (poster), presented at the 24th International AIDS Conference, Montreal. https://programme.aids2022.org/Abstract/Abstract/?abstractid=4243.

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Abstract: BACKGROUND: Progress towards HIV elimination in Western Africa may be hindered by diagnosis gaps among people living with HIV (PLHIV), especially among key populations (KP) such as female sex workers (FSW), their clients, and men who have sex with men (MSM). We aimed to identify largest gaps in diagnosis by risk group in Mali, Côte d'Ivoire, and Senegal, and project their contribution to new HIV infections. METHODS: Deterministic models of HIV transmission/diagnosis/treatment that incorporate HIV transmission among KP were parameterized following comprehensive country-specific reviews of demographic, behavioural, HIV and intervention data. The model was calibrated to country- and group-specific empirical outcomes such as HIV incidence/prevalence, the fractions of PLHIV ever tested, diagnosed, and on treatment. We estimated the distribution of undiagnosed PLHIV by risk group in 2020 and the population-attributable-fractions (tPAFs) (i.e. fraction of new primary and secondary HIV infections 2020-2029 originating from risk groups of undiagnosed PLHIV). RESULTS: From 46% (95% UI: 38-58) to 69% (59-79) of undiagnosed PLHIV in 2020 were males, with the lowest proportion in Mali and the highest proportion in Senegal, where 41% (28-59) of undiagnosed PLHIV were MSM. Undiagnosed men are estimated to contribute most new HIV infections occurring over 2020-2029 (Table). Undiagnosed FSW and their clients contribute substantial proportions of new HIV infections in Mali, with tPAF=20% (10-36) and tPAF=43% (26-56), respectively, while undiagnosed MSM in Senegal are estimated to contribute half of new infections. A lower proportion of new HIV infections are transmitted by undiagnosed KP in Côte d'Ivoire (tPAF=21%(10-38)). CONCLUSIONS: Current HIV testing services and approaches are leaving members of KP behind. Increasing the availability of confidential HIV testing modalities in addition to traditional tests may substantially reduce gaps in HIV diagnosis and accelerate the decrease of new HIV infections in Western Africa since half of them could be transmitted by undiagnosed KP.

Silhol et al. - 2022 - Identifying population-specific HIV diagnosis gaps.pdf 288.9 KiB

Simo Fotso Arlette, Johnson Cheryl, Vautier Anthony, Kouamé Konan Blaise, Diop Papa Moussa, Silhol Romain, Maheu-Giroux Mathieu, Boily Marie-Claude, Rouveau Nicolas, Doumenc-Aïdara Clémence, Baggaley Rachel, Ehui Eboi, Larmarange Joseph and ATLAS Team (2022) “Estimating the impact of HIV self-testing on HIV testing services, diagnoses, and treatment initiation at the population-level with routine data: the example of the ATLAS program in Côte d'Ivoire” (poster), presented at the 24th International AIDS Conference, Montreal. https://programme.aids2022.org/Abstract/Abstract/?abstractid=5409.

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Abstract: BACKGROUND: HIV self-testing (HIVST) is a critical testing approach particularly for reaching those at HIV risk who are hesitant or unable to access existing services. While the discreet and flexible nature of HIVST is appealing to users, these features can limit the ability for programmes to monitor and estimate the population-level impacts of HIVST implementation. This study triangulates publicly available routine programme data from Côte d'Ivoire in order estimate the effects of HIVST distribution on access to testing, conventional testing (self-testing excluded), HIV diagnoses, and antiretroviral treatment (ART) initiations. METHODS: We used quarterly programmatic data (Q3-2019 to Q1-2021) from ATLAS, a project that aims to promote and implement network-based HIVST distribution in West Africa, in addition to routine HIV testing services program data obtained from the PEPFAR dashboard. We performed ecological time series regression using linear mixed-models. RESULTS: Between Q3-2019 and Q1-2021, 99,353 HIVST kits were distributed by ATLAS in 78 health districts included in the analysis. The results (Table 1) show a negative but non-significant effect of the number of ATLAS HIVST on the volume of conventional tests (-190), suggesting the possibility of a slight substitution effect. Despite this, the the beneficial effect on access to testing is significant: for each 1000 HIVST distributed via ATLAS, 390 to 590 additional HIV tests were performed if 60% to 80% of HIVST are used . The effect of HIVST on HIV diagnosis was significant and positive, with 8 additional diagnoses per 1,000 HIVST distributed. No effect of HIVST was observed on ART initiations. CONCLUSIONS: Our study provides a standard methodology for estimating the population-level impact of HIVST that can be used across countries. It shows that HIVST distribution was associated with increased access to HIV testing and diagnosis in Côte d'Ivoire. Wide-scale adoption of this method will improve HIVST data quality and inform evidence-based programming.

Simo Fotso et al. - 2022 - Estimating the impact of HIV self-testing on HIV t.pdf 541.2 KiB

Stannah James, Flores Anato Jorge Luis, Mitchell Kate M, Larmarange Joseph, Maheu-Giroux Mathieu and Boily Marie‐Claude (2022) “Improving our understanding of how structural determinants impact HIV epidemics: a scoping review of dynamic models to guide future research” (poster), presented at the 24th International AIDS Conference, Montreal. https://programme.aids2022.org/Abstract/Abstract/?abstractid=6564.

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Abstract: BACKGROUND: Dynamic models of HIV transmission have proven valuable tools for informing HIV prevention strategies. Including structural determinants in models is crucial to estimate their population-level impacts on HIV transmission and inform efforts towards HIV elimination. However, this is challenging due to a lack of coherent conceptual frameworks, limited understanding of their specific causal pathways, and few empirical estimates of their impacts on downstream mediators. METHODS: With the overarching aim to improve models, we conducted a scoping review of studies that used dynamic HIV transmission models to evaluate the impact of structural determinants. From included studies, we extracted information on the types of structural determinants and methods used to model their impacts on HIV transmission. We appraised studies on how they conceptualized structural exposures and represented their causal relationships over time within models. RESULTS: We identified 9 dynamic transmission modelling studies that incorporated structural determinants of HIV, including violence (N=3), incarceration (N=2), stigma (N=2), housing instability (N=2), migration (N=1), and education (N=1). Only one study modelled multiple determinants simultaneously. In most models, structural determinants were conceptualized using current, recent, non-recent and/or lifetime exposure categories. Modelled structural determinants largely impacted HIV transmission through mediated effects on one or more proximate risk factors, including sharing injection equipment, condom use, number of partners, and access to treatment. However, causal pathways were simplistic, with few mediators and/or lack of clear empirical justification. To measure impact, most studies simply assumed the elimination of structural determinants in counterfactual comparison scenarios. Few models included long-term and/or delayed effects of past, recurrent, or acute exposure, potentially overestimating impacts of determinants. CONCLUSIONS: Despite the importance of structural determinants for HIV prevention, methods for including them in dynamic HIV transmission models remain insufficient. Few studies have attempted to incorporate structural determinants in HIV models, and methods vary considerably. To improve inferences, models should adopt precise exposure definitions, deconstruct and estimate their complex causal pathways, and translate them into their mechanistic components. The need for development of coherent frameworks to conceptualize the synergistic interplay between strengthened empirical data analysis and the inclusion of structural determinants in dynamic models is pressing.

Stannah et al. - 2022 - Improving our understanding of how structural dete.pdf 538.6 KiB

Joseph Larmarange

Comparing modelled HIV incidence estimates with empirical HIV incidence observations in high-burden HIV African epidemic settings: systematic review and meta-regression

Comparing modelled HIV incidence estimates with empirical HIV incidence observations in high-burden HIV African epidemic settings: systematic review and meta-regression

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Modélisation de l'impact épidémiologique potentiel du retrait du PEPFAR en Côte d'Ivoire, au Mali et au Sénégal

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Building better HIV models : a framework for incorporating evidence on structural determinants and interventions to estimate their impacts on HIV epidemics

Building better HIV models: a framework for incorporating evidence on structural determinants and interventions to estimate their impacts on HIV epidemics

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From conceptualising to modelling structural determinants and interventions in HIV transmission dynamics models: a scoping review and methodological framework for evidence-based analyses

From conceptualising to modelling structural determinants and interventions in HIV transmission dynamics models: a scoping review and methodological framework for evidence-based analyses

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Cost-effectiveness analysis of community-led HIV self-testing among key populations in Côte d'Ivoire, Mali, and Senegal

Cost‐effectiveness analysis of community‐led HIV self‐testing among key populations in Côte d'Ivoire, Mali, and Senegal

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Potential population-level effects of HIV self-test distribution among key populations in Côte d'Ivoire, Mali, and Senegal : a mathematical modelling analysis

Potential population-level effects of HIV self-test distribution among key populations in Côte d'Ivoire, Mali, and Senegal: a mathematical modelling analysis

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The impact of past HIV interventions and diagnosis gaps on new HIV acquisitions, transmissions, and HIV-related deaths in Côte d'Ivoire, Mali, and Senegal

The impact of past HIV interventions and diagnosis gaps on new HIV acquisitions, transmissions, and HIV-related deaths in Côte d'Ivoire, Mali, and Senegal

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Assessing the potential population-level impacts of HIV self-testing distribution among key populations in Cote d'Ivoire, Mali, and Senegal: a mathematical modelling analysis

Assessing the potential population-level impacts of HIV self-testing distribution among key populations in Cote d'Ivoire, Mali, and Senegal: a mathematical modelling analysis

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PrEP injectable dans les pays à ressources limitées, promesses et défis

PrEP injectable dans les pays à ressources limitées, promesses et défis

24th International AIDS Conference @ Montreal

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