A national cross-sectional study among drug-users in France: epidemiology of HCV and highlight on practical and statistical aspects of the design

Background

Epidemiology of HCV infection among drug users (DUs) has been widely studied. Prevalence and sociobehavioural data among DUs are therefore available in most countries but no study has taken into account in the sampling weights one important aspect of the way of life of DUs, namely that they can use one or more specialized services during the study period. In 2004–2005, we conducted a national seroepidemiologic survey of DUs, based on a random sampling design using the Generalised Weight Share Method (GWSM) and on blood testing.

Methods

A cross-sectional multicenter survey was done among DUs having injected or snorted drugs at least once in their life. We conducted a two stage random survey of DUs selected to represent the diversity of drug use. The fact that DUs can use more than one structure during the study period has an impact on their inclusion probabilities. To calculate a correct sampling weight, we used the GWSM. A sociobehavioral questionnaire was administered by interviewers. Selected DUs were asked to self-collect a fingerprick blood sample on blotting paper.

Results

Of all DUs selected, 1462 (75%) accepted to participate. HCV seroprevalence was 59.8% [95% CI: 50.7–68.3]. Of DUs under 30 years, 28% were HCV seropositive. Of HCV-infected DUs, 27% were unaware of their status. In the month prior to interview, 13% of DUs shared a syringe, 38% other injection parapharnelia and 81% shared a crack pipe. In multivariate analysis, factors independently associated with HCV seropositivity were age over 30, HIV seropositivity, having ever injected drugs, opiate substitution treatment (OST), crack use, and precarious housing.

Conclusion

This is the first time that blood testing combined to GWSM is applied to a DUs population, which improve the estimate of HCV prevalence. HCV seroprevalence is high, indeed by the youngest DUs. And a large proportion of DUs are not aware of their status. Our multivariate analysis identifies risk factors such as crack consumption and unstable housing.

[Management of 90 patients presenting with suspected severe acute respiratory syndrome. Experience of a collaboration between epidemiologists and clinicians facing an emerging infectious disease health alert]

Objectifs

Afin d'analyser les différences possibles d'évaluation entre les équipes opérationnelles épidémiologiques et cliniciennes dans la gestion d'une maladie épidémique émergente, et d'en tirer un enseignement pour la gestion de crises ultérieures, les caractéristiques des patients suspects de syndrome respiratoire aigu sévère (SRAS) hospitalisés dans un service parisien ont été décrites.

Patients et méthodes

Les 90 patients hospitalisés du 16 mars au 30 avril 2003 furent inclus dans cette étude prospective. Les données échangées avec les institutions sanitaires locales permirent à la fois une classification de cas officielle (« possibles », « probables », « exclus ») et une classification locale basée sur une adaptation de celle-ci, incluant une catégorie supplémentaire dans la graduation du risque, intermédiaire entre « possible » et « exclu » (« douteux »).

Résultats

L'évaluation initiale différait dans 39 % des cas (n = 35), sur des arguments épidémiologiques (n = 24) ou clinicobiologiques (n = 11). L'évaluation finale divergeait dans 54 % des cas (n = 47). Tous les patients furent officiellement considérés comme des cas « exclus » de SRAS, alors que 47 demeuraient des cas « possibles » ou « douteux » selon les cliniciens.

Conclusion

Une différence de perception existait dans environ 40 % des cas, sans impact en termes de diffusion épidémique ou d'exposition nosocomiale, puisqu'aucun cas probable de SRAS n'a été retenu parmi ces patients ou leur entourage. De la confrontation de ces perceptions différentes, mais complémentaires, peuvent émerger des enseignements enrichissant la gestion interdisciplinaire d'épidémies ultérieures.

[Incidence and risk factors of HCV infection in a cohort of intravenous drug users in the North and East of France]

BACKGROUND

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among intravenous drug users we conducted a prospective cohort study of HCV and HIV negative IVDU in the North and East of France.

METHODS

Two hundred and thirty-one IVDU who had injected drug at least once in their lifetime and were negative for anti-HCV and anti-HIV were followed-up every three months over a 12-month period. Serum anti-HCV and anti-HIV antibodies were tested at inclusion in the study and at the end of the follow-up. Data on injection practices and behaviours were collected at inclusion and at each visit, and a test for anti-HCV antibodies was performed on a saliva sample. When this proved positive, an ELISA test for serum anti-HCV antibodies was carried out.

RESULTS

Of the 231 participants included, 165 (71.4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9% (95% CI: 4.6-13.4) person-years for HCV infection. Among IVDU who injected at least once during the last 6 months HCV infection incidence was 11% (95% CI: 4.7-17.1) person-years. The multivariate analysis carried out on the inclusion data found female sex alone to be an independent predictive factor of HCV seroconversion. In a Cox proportional hazard multivariate analysis that took into account time-dependent exposures and covariates, we found that syringe and cotton sharing were, after adjusting for other covariates, the only independent predictive factors of HCV seroconversion: hazard ratio: 6.3 [corrected] (95% CI: 1.1-35.4; [corrected] p<0.05) and 16.4 (95% CI: 1.4-190.6; [corrected] p<0.05), respectively.

CONCLUSION

The transmission of the HCV virus persists among French IVDU despite an ongoing national harm reduction program. Injecting material and cotton sharing are the two major determinants of transmission in this cohort.

[Limited impact of the harm-reduction policy on HCV among drug-users. The ANRS-Coquelicot survey example]

BACKGROUND

In France, a harm-reduction policy was implemented in the late 1980s with the aim of reducing the prevalence of HIV and hepatitis C virus infection among drug users. The ANRS-Coquelicot survey was designed to measure the prevalence of HIV and HCV infection among drug users, and to examine determinants of at-risk behaviors.

METHODS

In 2002, information was collected from 166 drug users recruited in all types of services specializing in drug use and harm reduction in Marseille, France. Self-reported HIV and HCV serostatus was compared with the results of serological tests done on capillary blood collected on filter paper.

RESULTS

The self-reported and biologically documented prevalence rates of HIV infection were identical (22 %). In contrast, the self-reported prevalence of HCV infection was 52 %, while the biologically documented prevalence was 73 %. Overall, 30 % of HCV-infected drug users were unaware of their status. Forty-four per cent of drug users under 30 years of age were HCV-seropositive, suggesting that they had been infected early during drug use.

CONCLUSION

The harm-reduction policy seems to have had a marked impact on HIV transmission among drug users, but a much more limited impact on HCV transmission.

Impact of a harm-reduction policy on HIV and hepatitis C virus transmission among drug users: recent French data--the ANRS-Coquelicot Study

In France a harm-reduction policy was implemented in the late 1980s with the aim of reducing the prevalence of HIV and hepatitis C virus (HCV) infection among drug users. The ANRS-Coquelicot survey was designed to measure the prevalence of HIV and HCV infection among drug users and to examine determinants of at-risk behaviors. In 2002, information was collected from 166 drug users recruited in all types of services specializing in drug use intervention and harm reduction in Marseille, France. Self-reported HIV and HCV serostatus was compared with the results of serological tests done on capillary blood collected on filter paper. The self-reported and biologically documented prevalence rates of HIV infection were identical (22%). In contrast, the self-reported prevalence of HCV infection was 52%, whereas the biologically documented prevalence was 73%. Overall, 30% of HCV-infected drug users were unaware of their status. Forty-four percent of drug users under 30 years of age were HCV seropositive, suggesting that they had been infected early during drug use. The harm-reduction policy seems to have had a marked impact on HIV transmission among drug users but a much more limited impact on HCV transmission. The limitations and implications of the study are discussed.

Absence of infection in asymptomatic contacts of index SARS case in France

The first case of severe acute respiratory syndrome (SARS) in France was diagnosed in March 2003. We conducted a serological survey to assess whether or not asymptomatic persons who had been in contact with this patient during his infectious stage had been infected. They were interviewed and asked to provide a blood sample for SARS coronavirus immunoglobulin G antibody testing. Despite the likely high infectivity of the SARS patient, no asymptomatic SARS infection was found in any of the 37 contacts included. These findings support a SARS case definition that is essentially based on clinical and epidemiological assessment, should SARS re-emerge.

Absence of infection in asymptomatic contacts of index SARS case in France

The first case of severe acute respiratory syndrome (SARS) in France was diagnosed in March 2003. We conducted a serological survey to assess whether or not asymptomatic persons who had been in contact with this patient during his infectious stage had been infected. They were interviewed and asked to provide a blood sample for SARS coronavirus immunoglobulin G antibody testing. Despite the likely high infectivity of the SARS patient, no asymptomatic SARS infection was found in any of the 37 contacts included. These findings support a SARS case definition that is essentially based on clinical and epidemiological assessment, should SARS re-emerge.

Harm reduction interventions, behaviours and associated health outcomes in France, 1996-2003

AIMS

To track the effect of the French harm reduction programme targeted at intravenous drug users (IDUs) and associated health outcomes.

MATERIAL

Since 1996, we have collected monthly sales of sterile syringes and substitution treatments (buprenorphine high dosage and methadone) sold to IDUs in the 23 000 pharmacies in France and collated these figures in a single data base (SIAMOIS). To this data base we have also added the number of syringes distributed through community associations, as well as methadone treatments prescribed in public drug dependence clinics.

METHODS

For the period 1996-2003 we analysed syringe sales and prescribed substitution treatments as indicators of access to harm reduction services. We compared variations of these figures over time with trends in health outcome indicators [annual number of fatal overdoses, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) prevalence among intravenous drug users], risk behaviour indicators (rate of syringe sharing or rate of syringe re-use) and legal indicators (heroin and cocaine use-related arrests).

FINDINGS

The number of sterile syringes sold or distributed to IDUs increased from 1996 to 1999 (+ 21%) and then decreased dramatically from 1999 to 2003 (-40%). In 2003, we estimated that more than 100,000 drug users used substitution treatments. Between 1996 and 2003, a decrease in syringe sharing and syringe re-use was observed, HIV prevalence among IDUs decreased from 40% to 20% and HCV prevalence remained high (60-70%). From 1996 to 2003, arrests due to heroin use declined (from 17 328 to 4025) and deaths due to overdoses also decreased (from 465 to 89), whereas arrests for cocaine use increased from 1184 to 2511.

CONCLUSION

Our results indicate that, since 1996 in France, IDUs have had greatly improved access to sterile syringes and substitution treatments. The decrease in syringe sharing and re-use practices and of HIV prevalence during the same time period indicates that the harm reduction policy implemented in France has had a positive impact. However, because of the persistent sharing and re-use of syringes and a remaining high HCV prevalence in IDUs, efforts to facilitate access to sterile syringes must continue, and targeting of at-risk groups must be improved. Behavioural surveys associated with HIV and HCV seroprevalence data are needed to further assess prevention of blood-borne infections among IDUs in France.

Incidence and risk factors of HCV and HIV infections in a cohort of intravenous drug users in the North and East of France

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among injecting drug users (IDUs), we conducted a prospective cohort study of HCV- and human immunodeficiency virus (HIV)-negative IDUs in the North and East of France. A total of 231 HCV and HIV IDUs who had injected drugs at least once in their lifetime were followed up every 3 months over a 12-month period. Serum anti-HCV and anti-HIV were tested at inclusion in the study and at the end of the follow-up. Data on injecting practices were collected at inclusion and at each visit. Of the 231 participants included, 165 (71.4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9/100 person-years (95% CI 4.6-13.4) for HCV infection. In a multivariable analysis, we found that syringe and cotton sharing were the only independent predictive factors of HCV seroconversion.

[Harm reduction policy related to drug use: the needles exchange programs]

In several developed countries, needles exchange programs (NEPs) are a key preventive tool in harm reduction policy related to drug use. Many studies about NEP show it reduces HIV infections related to syringes sharing when part of others preventive actions. NEPs seem to have no impact on HCV transmission. Furthermore, young drug users, who are at high risk for HIV and HCV infections, are not attending NEPs very often. Trying to maintain high accessibility to sterile syringes, efforts must be stressed on hard-to-reach populations such as young injection drug users (IDU), focusing on their social network. Emphasis must also be put on prevention of unsafe sexual intercourse, often related to syringe sharing, which must be more prevented. Finally, design of assessment studies should be improved.

Introduction of SARS in France, March-April, 2003

We describe severe acute respiratory syndrome (SARS) in France. Patients meeting the World Health Organization definition of a suspected case underwent a clinical, radiologic, and biologic assessment at the closest university-affiliated infectious disease ward. Suspected cases were immediately reported to the Institut de Veille Sanitaire. Probable case-patients were isolated, their contacts quarantined at home, and were followed for 10 days after exposure. Five probable cases occurred from March through April 2003; four were confirmed as SARS coronavirus by reverse transcription-polymerase chain reaction, serologic testing, or both. The index case-patient (patient A), who had worked in the French hospital of Hanoi, Vietnam, was the most probable source of transmission for the three other confirmed cases; two had been exposed to patient A while on the Hanoi-Paris flight of March 22-23. Timely detection, isolation of probable case-patients, and quarantine of their contacts appear to have been effective in preventing the secondary spread of SARS in France.

[An inter-laboratory study of anti-HCV antibody detection in saliva samples]

AIM

The purpose of this study was to evaluate the efficacy of anti-hepatitis C virus (HCV) antibody detection in the saliva samples of 108 drug users in an inter-laboratory study.

METHODS

Between January and June 2001, 108 subjects in Lille, Metz and Lens received a test to detect anti-HCV antibodies in their saliva. Two consecutive saliva samples were taken in each subject (Salivette system, Sarstedt). An HCV serology (Axsym HCV 3.0, Abbott) was also performed and serum HCV RNA detection by Amplicor HCV 2.0 (Roche) was performed when HCV serology was positive. Sixty three patients had a negative HCV serology, 45 had a positive HCV serology, and 31 of these had positive HCV RNA as well. Tests for the detection of the anti HCV antibody in saliva samples were performed as a blind study in both the Lille and the Thionville laboratories.

RESULTS

The sensitivity of saliva anti-HCV antibody tests was respectively 71% (32/45) and 78% (35/45) in Lille and Thionville. In the event of positive HCV viremia, the sensitivity was respectively 90% (28/31) and 93% (29/31). The specificity was respectively 97% (61/63) and 98.5% (62/63). Results from the two laboratories agreed for 101 saliva tests while discrepancies were found in 7 (Kappa Concordance Coefficient: 0.85).

CONCLUSIONS

This study confirms, in a large, unselected population sample, that anti-HCV antibody detection tests in saliva allow the detection of 90% of viremic HCV-antibody-positive patients with excellent specificity. The simplicity and reproductibility of this technique makes it a precious tool for epidemiological studies.

Travel agents and the prevention of health problems among travelers in Québec

BACKGROUND

Among the factors influencing travelers to seek preventive health advice before departure, the travel agent's recommendation plays an important role. The objective of our study was to document the practices and needs of travel agents in Québec (Canada) in relation to the prevention of health problems among travelers.

METHODS

In June 2000, a cross-sectional descriptive survey was carried out among travel agents from all travel agencies in Québec. One agent per agency was asked to answer our questions. Data were collected using a 32-item telephone questionnaire.

RESULTS

Altogether, 708 travel agents from the 948 agencies contacted answered our questionnaire (participation rate: 75%). Most respondents (81%) believed that the travel agent has a role to play in the prevention of health problems among travelers, especially to recommend that travelers consult a travel clinic before departure. Although over 80% of the agents interviewed mentioned recommending a visit to a travel clinic before an organized tour to Thailand or a backpacking trip in Mexico, less than half said they make the same recommendation for a stay in a seaside resort in Mexico. The majority of respondents were acquainted with the services offered in travel health clinics, and these clinics were the source of travel health information most often mentioned by travel agents. However, nearly 60% of the agents questioned had never personally consulted a travel clinic. When asked about the best way to receive information about travelers' health, more than 40% of respondents favoured receiving information newsletters from public health departments regularly whereas 28% preferred the Internet.

CONCLUSION

Despite the limits of this study, our results should help the public health network better target its interventions aimed to inform travel agents on prevention of health problems among travelers.

[Screening for colorectal cancer. Study of a population attending a public health clinic]

OBJECTIVES

Screening for colorectal cancer with fecal occult-blood test has been performed in health centers for several years. The aim of this study was to describe participation rate and results in a population attending the Center for preventive medicine at Vandoeuvre-lès-Nancy, France in 1996 and 1997.

PATIENTS AND METHODS

Among 19,325 people aged 50-75 years, the screening test was proposed to 17,917 and performed in 15,527.

RESULTS

Participation rate was 86.7%. Overall positivity was 3.6% higher in men than in women (4.1% versus 3.0%). In the 440 colonoscopies performed, 22 cancers and 84 adenoma polyps were identified (PPV = 24%).

DISCUSSION

These results show good participation rates in a screening program for colorectal cancer during periodic health check-ups. Follow-up for positive subjects was satisfactory but requires good cooperation between specialists and general practitioners to obtain complete information to evaluate the program.

Unsafe injecting practices among attendees of syringe exchange programmes in France

AIMS

To describe syringe exchange programme attendees and their injection practices.

DESIGN

Cross-sectional study (one week in 1998). Data were collected through a standardized questionnaire.

SETTING

60/74 syringe exchange programmes (SEPs) in France.

PARTICIPANTS

Clients requesting syringes in 60 SEPs.

MEASUREMENTS

Self-reports of drug use, injecting behaviour, sexual behaviour, serological status (HIV, HBV, HCV). Prevalence of unsafe injecting practices in the previous month such as: syringe sharing; and sharing other injection paraphernalia.

FINDINGS

1004 questionnaires were collected (response rate: 50%). The mean age of respondents was 30 years, and 70% were males. Among individuals tested, HIV reported prevalence was 19.2%, HCV 58.4% and HBV 20.8%. The mean duration of drug use was 11 years. Eighty-five percent were polydrug users and buprenorphine high-dosage was the substance most used (73%). In the previous month, 45% of the participants had re-used a syringe, 93% injected at least daily (mean 3.6 injections per day), 18% shared a syringe and 71% shared injection paraphernalia. In multivariate analyses, unsafe injecting practices were associated with heroin and cocaine use and with living in a couple. The cluster analysis identified five categories of IDUs: users of buprenorphine-HD (45% of the responders), morphine-sulphate (17%), benzodiazepines and other legal drugs (13%), methadone associated with other legal drugs (13%) and crack-cocaine (13%). The buprenorphine-HD group had better social status and safer injection practices.

CONCLUSIONS

In France, despite an increase in the accessibility to syringes and substitution treatments, unsafe injecting practices persist among SEP attenders. Interventions should stress the importance of using sterile material for each injection, even with a steady sex partner.