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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p

Influenza Vaccine Effectiveness Against Influenza-Related Mortality in Australian Hospitalized Patients: A Propensity Score Analysis

BACKGROUND: Data on influenza vaccine effectiveness (IVE) against mortality are limited, with no Australian data to guide vaccine uptake. We aimed to assess IVE against influenza-related mortality in Australian hospitalized patients, assess residual confounding in the association between influenza vaccination and mortality, and assess whether influenza vaccination reduces the severity of influenza illness. METHODS: Data were collected between 2010 and 2017 from a national Australian hospital-based sentinel surveillance system using a case-control design. Adults and children admitted to the 17 study hospitals with acute respiratory symptoms were tested for influenza using nucleic acid testing; all eligible test-positive cases, and a subset of test-negative controls, were included. Propensity score analysis and multivariable logistic regression were used to determine the adjusted odds ratio (aOR) of vaccination, with IVE = 1 - aOR × 100%. Residual confounding was assessed by examining mortality in controls. RESULTS: Over 8 seasons, 14038 patients were admitted with laboratory-confirmed influenza. The primary analysis included 9298 cases and 6451 controls, with 194 cases and 136 controls dying during hospitalization. Vaccination was associated with a 31% (95% confidence interval [CI], 3%-51%; P = .033) reduction in influenza-related mortality, with similar estimates in the National Immunisation Program target group. Residual confounding was identified in patients ≥65 years old (aOR, 1.92 [95% CI, 1.06-3.46]; P = .031). There was no evidence that vaccination reduced the severity of influenza illness (aOR, 1.07 [95% CI, .76-1.50]; P = .713). CONCLUSIONS: Influenza vaccination is associated with a moderate reduction in influenza-related mortality. This finding reinforces the utility of the Australian vaccination program in protecting those most at risk of influenza-related deaths

Comparing injecting and non-injecting illicit opioid users in a multi-site Canadian sample (OPICAN cohort)

Illicit opioid use in Canada and elsewhere increasingly involves a variety of opioids and non-injection routes of administration. Injection and non-injection opioid users tend to differ in various key characteristics. From a public health perspective, non-injection routes of opioid use tend to be less harmful due to lesser morbidity and mortality risks. Our study compared current injectors (80%) and non-injectors (20%) in a multi-site sample of regular illicit opioid users from across Canada ('OPICAN' study). In bivariate analysis, injectors and non-injectors differed by prevalence in social and health characteristics as well as drug use. Logistic regression analysis identified city, drug use, housing status and mental health problems as independent predictors of injection status. Further analysis revealed that the majority of current non-injectors had an injection history. Our results reinforce the need to explore potential interventions aimed at preventing the transition from non-injectors to injecting, or facilitating the transition of injectors to non-injecting, as initiated in several other contexts

Boyfriends and booty calls: sexual partnership patterns among Canadian Aboriginal young people.

OBJECTIVES: Sexual partnership patterns, forced sex, and condom non-use can contribute to STI risk, but little is known about these patterns among Aboriginal young people despite elevated STI risk in this group. We describe sexual relationship and condom use patterns among Canadian Aboriginal young people, and how these patterns relate to the socio-structural context as experienced by young people. METHODS: We use data from in-depth individual interviews conducted in 2004 with 22 young people who reported ever having sex and who self-identified as Aboriginal in British Columbia, Canada. A thematic analysis is presented. RESULTS: Young people described a range of partnership patterns, including 'on-off' relationships which could have high rates of partner turnover but could sometimes be viewed as acceptable contexts for pregnancy, precluding condom use. Contextual elements beyond individual control appeared to contribute to these patterns. Migration between geographic locations was linked with risky partnership patterns, especially if it was linked with family instability or substance use problems. CONCLUSION: Sexual health interventions for this group must address partnership patterns in addition to promoting condom use. Survey research into 'migration' as a risk factor for STI transmission should consider reasons for migration. Interventions that address both individual level behaviour and the contextual elements that shape behaviour should be developed and tested

Syringe Sharing and HIV Incidence Among Injection Drug Users and Increased Access to Sterile Syringes

Objectives—We assessed the effects of syringe exchange program (SEP) policy on rates of HIV risk behavior and HIV incidence among injection drug users. Methods—Using a multivariate generalized estimating equation and Cox regression methods, we examined syringe borrowing, syringe lending, and HIV incidence among a prospective cohort of 1228 injection drug users in Vancouver, British Columbia. Results—We observed substantial declines in rates of syringe borrowing (from 20.1% in 1998 to 9.2% in 2003) and syringe lending (from 19.1% in 1998 to 6.8% in 2003) following SEP policy change. These declines coincided with a statistically significant increase in the proportion of participants accessing sterile syringes from nontraditional SEP sources (P<.001). In multivariate analyses, the period following the change in SEP policy was independently associated with a greater than 40% reduction in syringe borrowing (adjusted odds ratio [AOR]=0.57; 95% confidence interval [CI]=0.49, 0.65) and lending (AOR=0.52; 95% CI=0.45, 0.60), as well as declining HIV incidence (adjusted hazard ratio=0.13; 95% CI=0.06, 0.31). Conclusions—Widespread syringe distribution appears to be a more effective SEP policy than do more restrictive SEP policies that limit syringe access. Efforts should be made to ensure that SEP policies and program design serve to maximize rather than hinder syringe access.Medicine, Faculty ofOther UBCNon UBCMedicine, Department ofReviewedFacultyResearche