Nevirapine vs efavirenz in virologically supressed patients: Differences in lipoprotein subclasses and inflammatory biomarkers.

Background: The interaction between lipid disturbances and inflammatory markers is not well known in patients on antiretroviral therapy (ART). As nevirapine (NVP) is associated with a better lipid profile than efavirenz (EFV), we investigated the relationships between lipid profiles, lipoprotein subclasses and inflammatory biomarkers in patients with prolonged viral suppression with either NVP or EFV and no obvious clinical inflammation. Methods: 122 clinically stable HIV-infected patients with HIV-1 RNA <20 copies longer than 6 months on NNRTI therapy were studied. 72 (59%) were on EFV and 50 (41%) on NVP. Any potentially inflammatory co-morbid diseases (concurrent viral hepatitis, diabetes, hypertension, chronic liver or renal diseases), or statin treatment, were exclusion criteria. Inflammatory biomarkers included hsCRP, LpPLA2, sCD40L, IL-6, IL-8, t-PA, MCP-1, p-selectin and VCAM-1. Lipoprotein subclass measures (VLDL, LDL, IDL and HDL particle number and size) were obtained by the use of proton nuclear magnetic resonance spectroscopy. Results: 82% were male; median age 45 years. Median CD4 count 550/μL (IQR 324). Median time since HIV diagnosis 96 months (IQR 102) and accumulated time on ART 50 months (IQR 101). Patients on NVP had higher time since HIV diagnosis (126.9 [66.7] vs 91.3 [6.6] months, p=0.008) a prolonged time on ART (89.6 [54.6] vs 62.3 [52.2] months, p=0.01) and were older (47.7 vs 40.7 years, p=0.001) than those on EFV. NVP-treated patients presented increased HDL-c (55.8 [16] vs 48.8 [10.7] mg/dL, p=0.007) and apoA1 levels (153.4 [31.9] vs 141.5 [20.5] mg/dL, p=0.02), and reduced apoB/apoA1 ratio (0.68 [0.1] vs 0.61 [0.1], p=0.003) than EFV-treated patients. No differences in inflammatory markers or lipoprotein subclasses were found between NVP and EFV. In patients with extreme lipid values (less favorable: 75th percentiles of LDL, small/dense LDLp and small HDLp, or more favorable: HDL p75 and apoB/apoA1 ratio p25), no consistent differences in inflammatory biomarkers were found. Conclusions: Patients with prolonged viral suppression on NVP present significantly higher HDL and apoA1 levels and reduced apoB/apoA1 ratios than those on EFV, but no differences were found in lipoprotein particles nor inflammatory biomarkers. Relationships between lipid parameters and inflammatory biomarkers in NNRTItreated patients are complex and do not show a linear relationship in this study.

Increased alpha-defensins 1-3 production by dendritic cells in HIV-infected individuals is associated with slower disease progression.

Defensins are natural endogenous antimicrobial peptides with potent anti-HIV activity and immuno-modulatory effects. We recently demonstrated that immature dendritic cells (DC) produce α-defensins1-3 and that α-defensins1-3 modulate DC generation and maturation. Since DC-HIV interaction plays a critical role during the first steps of HIV infection, we investigated the possible impact of α-defensins1-3 production by DC on disease progression.

Increased alpha-defensins 1-3 production by dendritic cells in HIV-infected individuals is associated with slower disease progression.

Defensins are natural endogenous antimicrobial peptides with potent anti-HIV activity and immuno-modulatory effects. We recently demonstrated that immature dendritic cells (DC) produce α-defensins1-3 and that α-defensins1-3 modulate DC generation and maturation. Since DC-HIV interaction plays a critical role during the first steps of HIV infection, we investigated the possible impact of α-defensins1-3 production by DC on disease progression.

Modelling the evolution and spread of HIV immune escape mutants.

During infection with human immunodeficiency virus (HIV), immune pressure from cytotoxic T-lymphocytes (CTLs) selects for viral mutants that confer escape from CTL recognition. These escape variants can be transmitted between individuals where, depending upon their cost to viral fitness and the CTL responses made by the recipient, they may revert. The rates of within-host evolution and their concordant impact upon the rate of spread of escape mutants at the population level are uncertain. Here we present a mathematical model of within-host evolution of escape mutants, transmission of these variants between hosts and subsequent reversion in new hosts. The model is an extension of the well-known SI model of disease transmission and includes three further parameters that describe host immunogenetic heterogeneity and rates of within host viral evolution. We use the model to explain why some escape mutants appear to have stable prevalence whilst others are spreading through the population. Further, we use it to compare diverse datasets on CTL escape, highlighting where different sources agree or disagree on within-host evolutionary rates. The several dozen CTL epitopes we survey from HIV-1 gag, RT and nef reveal a relatively sedate rate of evolution with average rates of escape measured in years and reversion in decades. For many epitopes in HIV, occasional rapid within-host evolution is not reflected in fast evolution at the population level.

Le sens des messages préventifs du sida: consensus et dissensions au sien de la population générale

La recherche « Le sens des messages préventifs du sida » a été dirigée par une équipe de spécialistes relevant de domaines distincts - linguistique (Pr Pascal Singy), santé publique (Dre Brenda Spencer), médecine psychosociale (Pr Patrice Guex). Partant du constat que les langues naturelles n'existent que sous la forme de variétés, il a été postulé que le registre lexical du VIH/sida et de sa prévention n'échappe pas au principe de variabilité sémantique qui veut que, séparés par la multiplicité de leurs identités (sexe, appartenance socioculturelle, âge, etc.), les membres d'une « même » communauté linguistique tendent à associer à une unité lexicale donnée des significations différentes, voire antagonistes. Menée entre 2004 et 2006 en Suisse romande, la recherche « Le sens des messages préventifs du sida » s'appuie sur une approche sémantique de la prévention. Elle interroge les limites d'une communication préventive différée - par voie d'affiches et de brochures, en particulier - qui suppose que le destinataire ou récepteur d'un message en prend connaissance en l'absence de celui qui l'a émis. Les différents mécanismes conversationnels d'ajustement faisant à l'évidence défaut dans ce type de situation de communication, la variabilité sémantique peut dès lors apparaître problématique. S'agissant de l'objectif de cette recherche, il a essentiellement tenu dans la mise en évidence du degré de consensus que montrent les récepteurs (la population générale) ainsi que les émetteurs des messages préventifs à propos des significations attachées à des unités constitutives du lexique du VIH/sida et de sa prévention. Cette mise en évidence a par ailleurs permis d'évaluer la convergence des résultats obtenus pour les premiers et pour les seconds. Du point de vue méthodologique, un corpus de documents préventifs a été constitué - des brochures, principalement, publiées en français entre 1996 et 2004 - et analysé. Soixante et une unités lexicales, relevant du français commun ou spécialisé, ont alors été sélectionnées. L'ensemble de ces unités a été soumis à soixante représentants de la population générale vaudoise ainsi qu'à trente professionnels vaudois de la prévention dans le cadre d'entretiens en face à face. Ces entretiens ont permis de dégager les significations que ces deux populations attachent à une partie des unités lexicales (N=21) et le niveau d'intelligibilité/utilisation de l' autre partie des unités (N=40) - cf. infra *. Sur la base des résultats obtenus pour la population générale vaudoise, quinze unités lexicales apparues particulièrement problématiques ont été sélectionnées et soumises par le moyen d'une enquête téléphonique (CATI) à cinq cents Romands. Mêlant techniques qualitatives et quantitatives, la recherche « Le sens des messages préventifs du sida » apporte des résultats intéressant non plus seulement les agents de la prévention du VIH/sida, mais également les patients de celle-ci, c'est-à-dire la population générale. Des résultats qui se trouvent susceptibles de renforcer la portée de la prévention du VIH/sida en particulier dans la partie francophone de la Suisse. *Les unités lexicales sélectionnées sont les suivantes : abstinence, anus, caresses, coït anal, contact sexuel, contamination par voie sexuelle, coucher avec, cunnilingus, dépistage, « évitez le contact de la bouche avec du sperme ou du sang », faire l'amour, fellation, fidèle, gai, gay, immunisé, infection sexuellement transmissible, IST, liquides biologiques, maladies vénériennes, menstruation, MST, muqueuses, muqueuse buccale, muqueuses génitales, « pas de sperme dans la bouche », pathogène, pénétration, plaie ouverte, préservatif, préservatif féminin, prophylaxie de post-exposition [PEP], rapport bucco-génital, rapport sexuel, rapports sexuels non protégés, rapports sexuels oraux, rectum, relation anale, relation stable, relation vaginale, safer sex, sécrétions sexuelles, sécrétions vaginales, séronégatif, séropositif, sexe à moindre risque, sexe anal, sida, sperme, surcontamination, symptôme, système immunitaire, test d'anticorps VIH, test VIH, traitements antirétroviraux combinés, traitement combiné, trithérapies, urètre, vaginal, VIH, virus IH.

Interferon-gamma release assays for the diagnosis of tuberculosis and tuberculosis infection in HIV-infected adults: a systematic review and meta-analysis.

Background: Despite the widespread use of interferon-gamma release assays (IGRAs), their role in diagnosing tuberculosis and targeting preventive therapy in HIV-infected patients remains unclear. We conducted a comprehensive systematic review to contribute to the evidence-based practice in HIV-infected people. Methodology/Principal Findings: We searched MEDLINE, Cochrane, and Biomedicine databases to identify articles published between January 2005 and July 2011 that assessed QuantiFERON H -TB Gold In-Tube (QFT-GIT) and T-SPOT H .TB (T-SPOT.TB) in HIV-infected adults. We assessed their accuracy for the diagnosis of tuberculosis and incident active tuberculosis, and the proportion of indeterminate results. The search identified 38 evaluable studies covering a total of 6514 HIV-infected participants. The pooled sensitivity and specificity for tuberculosis were 61% and 72% for QFT-GIT, and 65% and 70% for T-SPOT.TB. The cumulative incidence of subsequent active tuberculosis was 8.3% for QFT-GIT and 10% for T-SPOT.TB in patients tested positive (one study each), and 0% for QFT-GIT (two studies) and T-SPOT.TB (one study) respectively in those tested negative. Pooled indeterminate rates were 8.2% for QFT-GIT and 5.9% for T-SPOT.TB. Rates were higher in high burden settings (12.0% for QFT-GIT and 7.7% for T-SPOT.TB) than in low-intermediate burden settings (3.9% for QFT-GIT and 4.3% for T-SPOT.TB). They were also higher in patients with CD4 + T-cell count, 200 (11.6% for QFT-GIT and 11.4% for T-SPOT.TB) than in those with CD4 + T-cell count $ 200 (3.1% for QFT-GIT and 7.9% for T-SPOT.TB). Conclusions/Significance: IGRAs have suboptimal accuracy for confirming or ruling out active tuberculosis disease in HIV-infected adults. While their predictive value for incident active tuberculosis is modest, a negative QFT-GIT implies a very low short- to medium-term risk. Identifying the factors associated with indeterminate results will help to optimize the use of IGRAs in clinical practice, particularly in resource-limited countries with a high prevalence of HIV-coinfection.

Modelling the Evolution and Spread of HIV Immune Escape Mutants.

During infection with human immunodeficiency virus (HIV), immune pressure from cytotoxic T-lymphocytes (CTLs) selects for viral mutants that confer escape from CTL recognition. These escape variants can be transmitted between individuals where, depending upon their cost to viral fitness and the CTL responses made by the recipient, they may revert. The rates of within-host evolution and their concordant impact upon the rate of spread of escape mutants at the population level are uncertain. Here we present a mathematical model of within-host evolution of escape mutants, transmission of these variants between hosts and subsequent reversion in new hosts. The model is an extension of the well-known SI model of disease transmission and includes three further parameters that describe host immunogenetic heterogeneity and rates of within host viral evolution. We use the model to explain why some escape mutants appear to have stable prevalence whilst others are spreading through the population. Further, we use it to compare diverse datasets on CTL escape, highlighting where different sources agree or disagree on within-host evolutionary rates. The several dozen CTL epitopes we survey from HIV-1 gag, RT and nef reveal a relatively sedate rate of evolution with average rates of escape measured in years and reversion in decades. For many epitopes in HIV, occasional rapid within-host evolution is not reflected in fast evolution at the population level.

Problemas de salud y la vulnerabilidad social en pacientes inmigrantes ingresados con patología infecciosa: estudio caso-control

Introducción. La necesidad de recursos sanitarios de la población inmigrante ha aumentado en los últimos años. El estudio de los problemas de salud y la vulnerabilidad social planteados durante el ingreso hospitalario de estos pacientes ayudaría a mejorar su cuidado. Pacientes y métodos. Estudio caso-control realizado en el Hospital Clínic de Barcelona. Se incluyeron pacientes inmigrantes ingresados con patología infecciosa de octubre de 2002 a septiembre de 2003. Los casos fueron apareados por edad, sexo e infección por virus de la inmunodeficiencia humana (VIH). Se evaluaron variables clínicas (visitas a Urgencias, días y número de ingresos, cantidad de procedimientos y fármacos, diagnóstico etiológico y control post alta) y de vulnerabilidad social (utilización de trabajo social, tarjeta sanitaria, cuidador de referencia, consumo de tóxicos, barrera idiomática y alta de enfermería). Resultados. Se estudiaron 102 pacientes (51 casos y 51 controles, todos varones). El 56% estaban infectados por VIH en ambos grupos. El número de procedimientos diagnósticos o terapéuticos fue mayor en el grupo de inmigrantes (p = 0,02), se llegó en menor proporción a un diagnóstico etiológico (el 82% frente al 98%, p = 0,021) y el número de visitas post alta fue inferior (el 55% frente al 77%, p = 0,04). Los pacientes inmigrantes tuvieron unos índices de vulnerabilidad social mayores que la población autóctona y en un 35% de ellos existía una barrera idiomática. Un menor número tenían tarjeta sanitaria (el 63% frente al 94%, p < 0,0001) y un número mayor tuvieron necesidad de traslado a un centro sociosanitario (el 16% frente al 2%, p = 0,01). Discusión La vulnerabilidad social de los pacientes inmigrantes influye en una menor obtención del diagnóstico etiológico, mayor número de procedimientos durante la hospitalización y un menor seguimiento posterior al alta.

Problemas de salud y la vulnerabilidad social en pacientes inmigrantes ingresados con patología infecciosa: estudio caso-control

Introducción. La necesidad de recursos sanitarios de la población inmigrante ha aumentado en los últimos años. El estudio de los problemas de salud y la vulnerabilidad social planteados durante el ingreso hospitalario de estos pacientes ayudaría a mejorar su cuidado. Pacientes y métodos. Estudio caso-control realizado en el Hospital Clínic de Barcelona. Se incluyeron pacientes inmigrantes ingresados con patología infecciosa de octubre de 2002 a septiembre de 2003. Los casos fueron apareados por edad, sexo e infección por virus de la inmunodeficiencia humana (VIH). Se evaluaron variables clínicas (visitas a Urgencias, días y número de ingresos, cantidad de procedimientos y fármacos, diagnóstico etiológico y control post alta) y de vulnerabilidad social (utilización de trabajo social, tarjeta sanitaria, cuidador de referencia, consumo de tóxicos, barrera idiomática y alta de enfermería). Resultados. Se estudiaron 102 pacientes (51 casos y 51 controles, todos varones). El 56% estaban infectados por VIH en ambos grupos. El número de procedimientos diagnósticos o terapéuticos fue mayor en el grupo de inmigrantes (p = 0,02), se llegó en menor proporción a un diagnóstico etiológico (el 82% frente al 98%, p = 0,021) y el número de visitas post alta fue inferior (el 55% frente al 77%, p = 0,04). Los pacientes inmigrantes tuvieron unos índices de vulnerabilidad social mayores que la población autóctona y en un 35% de ellos existía una barrera idiomática. Un menor número tenían tarjeta sanitaria (el 63% frente al 94%, p < 0,0001) y un número mayor tuvieron necesidad de traslado a un centro sociosanitario (el 16% frente al 2%, p = 0,01). Discusión La vulnerabilidad social de los pacientes inmigrantes influye en una menor obtención del diagnóstico etiológico, mayor número de procedimientos durante la hospitalización y un menor seguimiento posterior al alta.

Problemas de salud y la vulnerabilidad social en pacientes inmigrantes ingresados con patología infecciosa: estudio caso-control

Introducción. La necesidad de recursos sanitarios de la población inmigrante ha aumentado en los últimos años. El estudio de los problemas de salud y la vulnerabilidad social planteados durante el ingreso hospitalario de estos pacientes ayudaría a mejorar su cuidado. Pacientes y métodos. Estudio caso-control realizado en el Hospital Clínic de Barcelona. Se incluyeron pacientes inmigrantes ingresados con patología infecciosa de octubre de 2002 a septiembre de 2003. Los casos fueron apareados por edad, sexo e infección por virus de la inmunodeficiencia humana (VIH). Se evaluaron variables clínicas (visitas a Urgencias, días y número de ingresos, cantidad de procedimientos y fármacos, diagnóstico etiológico y control post alta) y de vulnerabilidad social (utilización de trabajo social, tarjeta sanitaria, cuidador de referencia, consumo de tóxicos, barrera idiomática y alta de enfermería). Resultados. Se estudiaron 102 pacientes (51 casos y 51 controles, todos varones). El 56% estaban infectados por VIH en ambos grupos. El número de procedimientos diagnósticos o terapéuticos fue mayor en el grupo de inmigrantes (p = 0,02), se llegó en menor proporción a un diagnóstico etiológico (el 82% frente al 98%, p = 0,021) y el número de visitas post alta fue inferior (el 55% frente al 77%, p = 0,04). Los pacientes inmigrantes tuvieron unos índices de vulnerabilidad social mayores que la población autóctona y en un 35% de ellos existía una barrera idiomática. Un menor número tenían tarjeta sanitaria (el 63% frente al 94%, p < 0,0001) y un número mayor tuvieron necesidad de traslado a un centro sociosanitario (el 16% frente al 2%, p = 0,01). Discusión La vulnerabilidad social de los pacientes inmigrantes influye en una menor obtención del diagnóstico etiológico, mayor número de procedimientos durante la hospitalización y un menor seguimiento posterior al alta.

Problemas de salud y la vulnerabilidad social en pacientes inmigrantes ingresados con patología infecciosa: estudio caso-control

Introducción. La necesidad de recursos sanitarios de la población inmigrante ha aumentado en los últimos años. El estudio de los problemas de salud y la vulnerabilidad social planteados durante el ingreso hospitalario de estos pacientes ayudaría a mejorar su cuidado. Pacientes y métodos. Estudio caso-control realizado en el Hospital Clínic de Barcelona. Se incluyeron pacientes inmigrantes ingresados con patología infecciosa de octubre de 2002 a septiembre de 2003. Los casos fueron apareados por edad, sexo e infección por virus de la inmunodeficiencia humana (VIH). Se evaluaron variables clínicas (visitas a Urgencias, días y número de ingresos, cantidad de procedimientos y fármacos, diagnóstico etiológico y control post alta) y de vulnerabilidad social (utilización de trabajo social, tarjeta sanitaria, cuidador de referencia, consumo de tóxicos, barrera idiomática y alta de enfermería). Resultados. Se estudiaron 102 pacientes (51 casos y 51 controles, todos varones). El 56% estaban infectados por VIH en ambos grupos. El número de procedimientos diagnósticos o terapéuticos fue mayor en el grupo de inmigrantes (p = 0,02), se llegó en menor proporción a un diagnóstico etiológico (el 82% frente al 98%, p = 0,021) y el número de visitas post alta fue inferior (el 55% frente al 77%, p = 0,04). Los pacientes inmigrantes tuvieron unos índices de vulnerabilidad social mayores que la población autóctona y en un 35% de ellos existía una barrera idiomática. Un menor número tenían tarjeta sanitaria (el 63% frente al 94%, p < 0,0001) y un número mayor tuvieron necesidad de traslado a un centro sociosanitario (el 16% frente al 2%, p = 0,01). Discusión La vulnerabilidad social de los pacientes inmigrantes influye en una menor obtención del diagnóstico etiológico, mayor número de procedimientos durante la hospitalización y un menor seguimiento posterior al alta.

A human immune data-informed vaccine concept elicits strong and broad T-cell specificities associated with HIV-1 control in mice and macaques

Background: None of the HIV T-cell vaccine candidates that have reached advanced clinical testing have been able to induce protective T cell immunity. A major reason for these failures may have been suboptimal T cell immunogen designs. Methods: To overcome this problem, we used a novel immunogen design approach that is based on functional T cell response data from more than 1,000 HIV-1 clade B and C infected individuals and which aims to direct the T cell response to the most vulnerable sites of HIV-1. Results: Our approach identified 16 regions in Gag, Pol, Vif and Nef that were relatively conserved and predominantly targeted by individuals with reduced viral loads. These regions formed the basis of the HIVACAT T-cell Immunogen (HTI) sequence which is 529 amino acids in length, includes more than 50 optimally defined CD4+ and CD8+ T-cell epitopes restricted by a wide range of HLA class I and II molecules and covers viral sites where mutations led to a dramatic reduction in viral replicative fitness. In both, C57BL/6 mice and Indian rhesus macaques immunized with an HTI-expressing DNA plasmid (DNA.HTI) induced broad and balanced T-cell responses to several segments within Gag, Pol, and Vif. DNA.HTI induced robust CD4+ and CD8+ T cell responses that were increased by a booster vaccination using modified virus Ankara (MVA.HTI), expanding the DNA.HTI induced response to up to 3.2% IFN-γ T-cells in macaques. HTI-specific T cells showed a central and effector memory phenotype with a significant fraction of the IFN-γ+ CD8+ T cells being Granzyme B+ and able to degranulate (CD107a+). Conclusions: These data demonstrate the immunogenicity of a novel HIV-1 T cell vaccine concept that induced broadly balanced responses to vulnerable sites of HIV-1 while avoiding the induction of responses to potential decoy targets that may divert effective T-cell responses towards variable and less protective viral determinants.

Gp120/CD4 blocking antibodies are frequently elicited in ART-naïve chronically HIV-1 infected individuals

Antibodies with the ability to block the interaction of HIV-1 envelope glycoprotein (Env) gp120 with CD4, including those overlapping the CD4 binding site (CD4bs antibodies), can protect from infection by HIV-1, and their elicitation may be an interesting goal for any vaccination strategy. To identify gp120/CD4 blocking antibodies in plasma samples from HIV-1 infected individuals we have developed a competitive flow cytometry-based functional assay. In a cohort of treatment-naïve chronically infected patients, we showed that gp120/ CD4 blocking antibodies were frequently elicited (detected in 97% plasma samples) and correlated with binding to trimeric HIV-1 envelope glycoproteins. However, no correlation was observed between functional CD4 binding blockade data and titer of CD4bs antibodies determined by ELISA using resurfaced gp120 proteins. Consistently, plasma samples lacking CD4bs antibodies were able to block the interaction between gp120 and its receptor, indicating that antibodies recognizing other epitopes, such as PGT126 and PG16, can also play the same role. Antibodies blocking CD4 binding increased over time and correlated positively with the capacity of plasma samples to neutralize the laboratory-adapted NL4.3 and BaL virus isolates, suggesting their potential contribution to the neutralizing workforce of plasma in vivo. Determining whether this response can be boosted to achieve broadly neutralizing antibodies may provide valuable information for the design of new strategies aimed to improve the anti-HIV-1 humoral response and to develop a successful HIV- 1 vaccine.

HIV-1 immune activation induces siglec-1 expression and enhances viral trans-infection in blood and tissue myeloid cells

Background: Myeloid cells are key players in the recognition and response of the host against invading viruses. Paradoxically, upon HIV-1 infection, myeloid cells might also promote viral pathogenesis through trans-infection, a mechanism that promotes HIV-1 transmission to target cells via viral capture and storage. The receptor Siglec-1 (CD169) potently enhances HIV-1 trans-infection and is regulated by immune activating signals present throughout the course of HIV-1 infection, such as interferon α (IFNα). Results: Here we show that IFNα-activated dendritic cells, monocytes and macrophages have an enhanced ability to capture and trans-infect HIV-1 via Siglec-1 recognition of viral membrane gangliosides. Monocytes from untreated HIV-1-infected individuals trans-infect HIV-1 via Siglec-1, but this capacity diminishes after effective antiretroviral treatment. Furthermore, Siglec-1 is expressed on myeloid cells residing in lymphoid tissues, where it can mediate viral trans-infection. Conclusions: Siglec-1 on myeloid cells could fuel novel CD4+ T-cell infections and contribute to HIV-1 dissemination in vivo.

Évaluation du besoin et de la pertinence de l'implantation d'un service d'injection supervisée en Montérégie

This research project aimed to conduct a strategic analysis of the implementation of a supervised injecting facility (SIF) in Montérégie. Using a mixed design, we first completed a portrait of the injection drug user (IDU) population. We then explored the perceptions of IDU and stakeholders with regard to the relevance of implementing a SIF in the region. Although some similarities were found with the IDU populations of Montreal and the province of Quebec, this population in Montérégie is characterized by a lower frequency of injections in public, less homeless people and lower rates of HIV and HCV infections. Despite these differences, the IDU population in Montérégie was found to have important physical and psychosocial needs. Although the relevance of a SIF in Montérégie is undeniable, improvements regarding the accessibility, continuity and appreciation of the actual services dedicated to IDU remain a priority.