Estimating the Consensus hepatitis C Cascade of Care among people who inject drugs in Australia: Pre and post availability of direct acting antiviral therapy

Background Monitoring the hepatitis C virus (HCV) cascade of care (CoC) among people who inject drugs (PWID) is an essential component of the response to World Health Organisation's (WHO) hepatitis elimination goals. This study aimed to estimate the Consensus hepatitis C CoC among PWID using data collected in Australia prior to and after the introduction of unrestricted direct-acting antiviral (DAA) therapy in March 2016. Methods The Australian Needle Syringe Program Survey is a cross-sectional bio-behavioural surveillance system that recruits >2000 PWID annually. Using data from 2015 and 2019, HCV antibody and ribonucleic acid (RNA) test results from dried blood spots were combined with self-reported data on HCV diagnostic testing and treatment to project HCV Consensus CoC indicators at a population-level among Australian PWID. Results Among an estimated 75,000 people who inject drugs on a regular basis in Australia, the number with active HCV infection declined from 32,619 (44%) in October 2015 to 12,679 (17%) in October 2019. The majority (78% in 2015 and 2019) of PWID reported HCV diagnosis, while the proportion of those diagnosed who were treated increased from 3% in 2015 to 47% in 2019. Among those treated, the proportion who were HCV RNA negative and assumed to have been successfully treated (cured), increased from 27% in 2015 to 88% in 2019. Conclusion This study demonstrates remarkable HCV CoC progress among PWID in Australia following availability of DAA therapy. There was a substantial increase in the proportion of HCV diagnosed PWID who initiated treatment and were cured, while the number of PWID with active HCV infection more than halved over a 3.5 year period. Estimates of the Consensus hepatitis C CoC among PWID is required to monitor progress toward WHO HCV elimination goals.

Hepatitis C virus prevalence and associated risk factors among Indigenous Australians who inject drugs

OBJECTIVE

To examine factors associated with hepatitis C virus (HCV) infection among a national sample of Indigenous and non-Indigenous people who inject drugs (PWID) in Australia.

METHODS

Respondents were recruited from Australia's Needle Syringe Program Survey; an annual bio-behavioural surveillance project that monitors HCV antibody prevalence among PWID. Data from 2006-2015 were de-duplicated to retain only one record where individuals participated in >1 survey round. Univariate and multivariable logistic regression examined demographic characteristics and injection-related behaviours associated with exposure to HCV.

RESULTS

Among 17,413 respondents, 2,215 (13%) were Indigenous Australians. Compared to their non-Indigenous counterparts, Indigenous respondents were significantly more likely to be exposed to HCV infection (53% vs. 60% respectively, p<0.001). Among Indigenous respondents, HCV antibody positivity was independently associated with a history of imprisonment (Adjusted Odd Ratio [AOR] 2.13, 95%CI 1.73-2.64), opioid injection (AOR 1.53, 95%CI 11.43-2.16), recruitment in a metropolitan location (AOR 1.27, 95%CI 1.02-1.59), engagement in opioid substitution therapy (AOR 2.83, 95%CI 2.23-3.59) and length of time since first injection (p<0.001).

CONCLUSION

Indigenous PWID are more likely to be exposed to HCV infection than their non-Indigenous counterparts. Implications for public health: Increased access to culturally sensitive harm reduction programs is required to prevent primary HCV infection and reinfection among Indigenous PWID. Given recent advances in HCV treatment, promotion of treatment uptake among Indigenous PWID may reduce future HCV-related morbidity and mortality.

Trends in hepatitis C antibody prevalence among Aboriginal and Torres Strait Islander people attending Australian Needle and Syringe Programs, 1996-2015

BACKGROUND

Research indicates that hepatitis C antibody (anti-HCV) prevalence is higher among Australian Aboriginal and Torres Strait Islander (Aboriginal) than non-Aboriginal people who inject drugs (PWID). We examined trends in demographic and drug use characteristics and anti-HCV prevalence among Australian Needle and Syringe Program Survey (ANSPS) respondents by Aboriginal status from 1996 to 2015.

METHODS

The ANSPS survey involved collecting demographic, behavioural data and a dried blood spot for anti-HCV testing. We used logistic regression to determine demographic and behavioural factors associated with testing anti-HCV positive in the following time-periods (1996-2000, 2001-2005, 2006-2010, 2011-2015) among Aboriginal and non-Aboriginal PWID respondents.

RESULTS

Overall, there were 16,948 PWID, with 11% identifying as Aboriginal. The proportion of Aboriginal respondents increased from 7% in 1996-2000 to 16% in 2011-2015. Overall anti-HCV prevalence was significantly higher among Aboriginal (60%) than non-Aboriginal PWID (52%, p<0.01). Receptive syringe sharing (RSS) declined among non-Aboriginal PWID (p<0.001) over time, however among Aboriginal PWID, RSS remained stable (p=0.619). Factors independently associated with testing positive for anti-HCV among Aboriginal PWID in 2011-2015 were 16 or more years since first injection (adjusted odds ratio [AOR] 6.04, p<0.001), history of incarceration (AOR: 1.74, p=0.010) and currently or previously on opioid substitution therapy (AOR: 1.89, p=0.003). Compared to 1996-2000, testing anti-HCV positive was significantly associated with the time-periods: 2001-2005 (unadjusted odds ratio [OR]: 1.39, p<0.001), 2006-2010 (OR: 1.38, p<0.001) and 2011-2015 (OR: 1.25, p<0.001) among non-Aboriginal PWID; however this increase did not occur among Aboriginal PWID.

CONCLUSION

The proportion of Aboriginal PWID attending Needle Syringe Programs appears to have increased. Overall, the prevalence of anti-HCV has remained higher among Aboriginal than non-Aboriginal PWID. Coupling increased access to NSPs with new interferon-free HCV treatments and culturally appropriate education and counselling services could influence new HCV infections among Aboriginal PWID.

High risk injecting behaviour among people who inject pharmaceutical opioids in Australia

BACKGROUND

Use of opioid analgesic medicines has doubled globally over the past decade, with a concomitant increase in prevalence of injection of pharmaceutical opioids (PO), including in Australia. This study investigates types of PO injected, methods used to prepare PO for injection and correlates of recent (last 6 months) PO injection among a large national sample of people who inject drugs (PWID).

METHODS

The Australian NSP Survey (ANSPS), conducted annually at ∼50 NSP services across Australia, consists of a brief self-administered questionnaire and provision of a capillary dried blood spot for HIV and hepatitis C antibody testing. Data from 2014 were used to conduct univariable and multivariable logistic regression analysis to determine factors independently associated with recent injection of PO.

RESULTS

Among 1488 ANSPS respondents who were identified as opioid injectors, 57% (n=848) reported injection of PO in the previous six months. The majority of PO injectors (85%) reported filtering PO prior to injection, although use of efficacious wheel filters was relatively rare (11%). Correlates of POs injection included daily injection (AOR=1.65, 95% CI 1.31-2.08), receptive sharing of syringes (AOR=2.00, 95% CI 1.43-2.78), receptive sharing of drug preparation equipment (AOR=1.55, 95% CI 1.19-2.01), drug overdose in the previous year (AOR=1.81, 95% CI 1.36-2.42) and residence in inner regional (AOR=3.27, 95% CI 2.21-5.23) or outer regional/remote (AOR=5.50, 95% CI 3.42-8.84) areas of Australia.

CONCLUSION

PO injection is geographically widespread among Australian PWID and takes place in the context of poly-drug use. People who inject POs are at high risk of overdose, injection related injury and disease and blood borne viral infections. Harm reduction services that target this group, including in non-urban areas, should deliver health education regarding PO-specific overdose risks, the requirement to adequately filter PO before injection and to ensure that both naloxone and specialist pill filters are readily accessible.

Injecting Drug Users Retention in Needle-Exchange Program and its Determinants in Iran Prisons

BACKGROUND

Participation and to stay in a health program depends on many factors. One of these programs is Needle Exchange Program (NEP) in prisons.

OBJECTIVES

The current study aimed to evaluate the retention of injecting drug prisoners and find the related factors in Iran.

PATIENTS AND METHODS

This cohort study analyzed data about injecting drug male prisoners who were participated in NEP in three Iranian prisons. Data was collected from October 2009 to June 2010. A proper approach of survival analyses including Kaplan-Meier method, Log-Rank test, and Cox Proportional Hazard Model were used to evaluate Injecting Drug Users (IDUs) retention in NEP and its determinants.

RESULTS

Out of 320 prisoners, 167 were from Isfahan Central Prison, 82 from Tehran-Ghezel-Hesar Prison, and 71 from Hamadan Central Prison. Two-hundred and fifty prisoners (78.4%) had history of drug injection; and drug injection was the most common choice for 115 persons (35.9%). Participants were followed up for 29 weeks, the mean (SD) time of retention in the program was 24.1 (0.6) weeks. There was a significant relationship between age, number of used needles per week, duration of addiction, age of addiction onset, as well as imprisonment age, main method of drug use, type of main using drug, Hepatitis B Virus (HBV) infection, job status, reason of arrestment, history of involvement in harm reduction programs, and the length of retention (P < 0.05). There was also significant relationship between the history of using harm reduction services (P = 0.007), tattooing (P = 0.01), longer durations of addiction (P = 0.048), and retention.

CONCLUSIONS

Tattooing and longer duration of addiction were two important factors that significantly increased retention in the program. In contrast, history of using harm reduction services was the factor that decreased persistence. The risk of quitting the program may decrease about 68% in those who did not involve in harm reduction programs.

Performance and image enhancing drug injectors' access to needle syringe programs: Responding to a public policy dilemma

BACKGROUND

The number of people who inject performance and image enhancing drugs (PIEDs) attending Australian needle syringe programs (NSPs) has increased recently with cost and capacity implications for this already stretched public health program. The need to prioritise populations' NSP access poses dilemmas for a program that has always sought to minimise entry barriers.

METHODS

To assess their injecting-related risk of HIV and HCV, the Kirketon Road Centre (KRC) surveyed PIEDs injectors attending its two NSPs in inner Sydney in late 2013. Demographic, injecting risk, HIV and HCV testing, and NSP access data were analysed and then compared with similar data collected in the Australian Needle Syringe Program Survey (ANSPS) and the NSW NSP Enhanced Data Collection (NNEDC) survey conducted in the state of NSW in the same time period.

RESULTS

PIEDs injectors surveyed (n=103) were predominantly male (99%) and only one reported ever receptive needle syringe sharing any injecting equipment. KRC participants were similar to the other survey populations in having rarely ever injected intravenously (6%); being tested for HIV and HCV in the last year (44% and 32% respectively), and reporting low rates of HCV (0%). But they were much more likely to be gay or bisexual (42% vs 2% and 4% in the NSW surveys, p<0.001). Compared to their heterosexual counterparts at KRC, this subgroup was older (35 vs 31 years, p=0.011), and more likely to: have been injecting for <3 years (70% vs 44%, p=0.025); to have ever been tested for HIV (88% vs 46%, p<0.001); to have been tested for HIV and HCV in the last year (72% vs 24%, p<0.001 and 51% vs 19%, p=0.001 respectively); and to report being HIV positive (9% vs 0%, p<0.001).

CONCLUSIONS

PIEDs injectors with no other risk factors were at low risk of HIV and HCV, informing KRC's more targeted approach to their health needs. This included providing PIEDs-focused health information and promoting more frequent BBI testing, while encouraging injecting equipment access through other legal sources. This is a case study of how evidence can help resolve public policy dilemmas at the local level, thereby ensuring that scarce public health resources continue to be directed towards those people who inject drugs most at risk of BBIs.

HIV and Hepatitis C Virus Infection and Risk Behaviors Among Heterosexual, Bisexual, and Lesbian Women Who Inject Drugs in Australia

PURPOSE

Women who inject drugs (WWID) are vulnerable to a range of harms, including exposure to sexually transmitted and blood-borne infections, abusive relationships, physical and sexual violence and mental health issues. Lesbians and bisexual women are at greater risk than heterosexual women for substance use disorders. This study aimed to compare a large sample of heterosexual, bisexual, and lesbian WWID and to identify correlates of sexual orientation.

METHODS

The Australian Needle and Syringe Program (NSP) Survey is an annual cross-sectional survey. People who inject drugs (PWID) who attend NSP services are invited to complete a brief self-administered questionnaire and provide a capillary dried blood spot. Of 22,791 survey respondents between 2004-2013, one third were women (n=7,604). Analyses were restricted to the first participation record for each respondent.

RESULTS

Of the 5,378 individual women, 4,073 (76%) identified as heterosexual, 1,007 (19%) identified as bisexual, and 298 (6%) identified as lesbian. HIV prevalence was low (<1.0%). More than half (56%) had been exposed to hepatitis C virus (HCV), with prevalence highest among bisexual women (59%). In adjusted analysis, bisexual women had significantly greater odds of initiating injection at a younger age (AOR 1.44, 95% CI 1.19-1.73), and reporting public injection (AOR 1.44, 95% CI 1.21-1.73) and receptive sharing of drug preparation equipment (AOR 1.20, 95% CI 1.00-1.44). Bisexual women (AOR 1.42, 95% CI 1.07-1.88) and lesbians (AOR 1.63, 95% CI 1.10-2.44) had significantly greater odds of reporting sex work than their heterosexual counterparts.

CONCLUSION

Results contribute to the literature on HIV and HCV transmission risk among WWID. Analysis of the relationship between sexual orientation and risk behavior identified bisexual orientation as independently associated with increased risk. Services that target PWID need to recognise and address a broad range of sexual identities and behaviors. Future research should explore reasons for increased risk in sexual minority women.

Two decades of successes and failures in controlling the transmission of HIV through injecting drug use in England and Wales, 1990 to 2011

Responses to injecting drug use have changed focus over the last 20 years. Prevalence and incidence of human immunodeficiency virus (HIV) among people who inject drugs (PWID) in England and Wales were examined in relation to these changes. A voluntary unlinked-anonymous surveillance study obtained a biological sample and questionnaire data from PWID through annual surveys since 1990. Prevalence and incidence trends were estimated via generalised linear models, and compared with a policy time-line. Overall HIV prevalence among 38,539 participations was 1.15%. Prevalence was highest among those who started injecting before 1985; throughout the 1990s, prevalence fell in this group and was stable among those who started injecting later. Prevalence was higher in 2005 than 2000 (odds ratio: 3.56 (95% confidence interval (CI) 1.40–9.03) in London, 3.40 (95% CI 2.31–5.02) elsewhere). Estimated HIV incidence peaked twice, around 1983 and 2005. HIV was an important focus of policy concerning PWID from 1984 until 1998. This focus shifted at a time when drug use and risk were changing. The increased incidence in 2005 cannot be ascribed to the policy changes, but these appeared to be temporally aligned. Policy related to PWID should be continually reviewed to ensure rapid responses to increased risk.

Uptake of hepatitis C treatment among people who inject drugs attending Needle and Syringe Programs in Australia, 1999-2011

The majority of new and existing cases of hepatitis C virus (HCV) infection occur among people who inject drugs (PWID). Despite safe and efficacious HCV antiviral therapy, uptake remains low in this population. This study examined trends in HCV treatment uptake among a large national sample of PWID attending Australian Needle and Syringe Programs between 1999 and 2011. Annual cross-sectional sero-surveys conducted among PWID since 1995 involve completion of a self-administered questionnaire and provision of a dried blood spot for HCV antibody testing. Multivariate logistic regression identified variables independently associated with HCV treatment uptake among 9478 participants with both self-reported and serologically confirmed prior HCV infection. Between 1999 and 2011, the proportion currently receiving treatment increased from 1.1% to 2.1% (P < 0.001), while the proportion having ever received treatment increased from 3.4% to 8.6% (P < 0.001). Men were significantly more likely than women to have undertaken HCV treatment (P = 0.002). Among men, independent predictors of HCV treatment uptake were homosexual identity and older age; among women, independent predictors included homosexual identity and an incarceration history. Despite increases in HCV treatment among Australian PWID between 1999 and 2011, uptake remains low. Strategies are required to increase the proportion of PWID assessed and treated for HCV infection to address the increasing burden of disease. Specific approaches that target women may also be warranted. Continued surveillance of HCV treatment uptake among PWID will be important to monitor the roll-out of simple, safe and more effective HCV treatments expected to be available in the future.

Extremely low and sustained HIV incidence among people who inject drugs in a setting of harm reduction

This study created a retrospective cohort by linking repeat respondents in a large, national, annual cross-sectional sero-survey to estimate HIV incidence among people who inject drugs (PWID) in Australia. The results indicate extremely low and sustained rates of HIV incidence (0.11 per 100 person-years) over almost two decades (1995-2012). The findings demonstrate that sustained prevention of HIV transmission among PWID is possible and suggest that the early establishment and rapid scale-up of needle and syringe programmes, at a time when background prevalence was low, likely contributed to the prevention of an HIV epidemic among Australian PWID.

Housing instability among people who inject drugs: results from the Australian needle and syringe program survey

High rates of substance dependence are consistently documented among homeless people, and are associated with a broad range of negative outcomes among this population. Investigations of homelessness among drug users are less readily available. This study examined the prevalence and correlates of housing instability among clients of needle syringe programs (NSPs) via the Australian NSP Survey, annual cross-sectional seroprevalence studies among NSP attendees. Following self-completion of a brief, anonymous survey and provision of a capillary blood sample by 2,396 NSP clients, multivariate logistic regressions identified the variables independently associated with housing instability. Nineteen percent of ANSPS participants reported current unstable housing, with primary ('sleeping rough'; 5 %), secondary (staying with friends/relatives or in specialist homelessness services; 8 %), and tertiary (residential arrangements involving neither secure lease nor private facilities; 6 %) homelessness all evident. Extensive histories of housing instability were apparent among the sample: 66 % reported at least one period of sleeping rough, while 77 % had shifted between friends/relatives (73 %) and/or resided in crisis accommodation (52 %). Participants with a history of homelessness had cycled in and out of homelessness over an average of 10 years; and one third reported first being homeless before age 15. Compared to their stably housed counterparts, unstably housed participants were younger, more likely to be male, of Indigenous Australian descent, and to report previous incarceration; they also reported higher rates of key risk behaviors including public injecting and receptive sharing of injecting equipment. The high prevalence of both historical and current housing instability among this group, particularly when considered in the light of other research documenting the many adverse outcomes associated with this particular form of disadvantage, highlights the need for increased supply of secure, affordable public housing in locations removed from established drug markets and serviced by health, social, and welfare support agencies.

Reduction in HCV incidence among injection drug users attending needle and syringe programs in Australia: a linkage study

OBJECTIVES

We examined trends in HCV incident infection among injection drug users (IDUs) attending needle and syringe programs (NSPs) in Australia in 1995 to 2010.

METHODS

We created a passive retrospective cohort of 724 IDUs who tested negative for HCV antibodies by a simple deterministic method linking partial identifiers to find repeat respondents in annual cross-sectional serosurveillance.

RESULTS

We identified 180 HCV seroconversions over the study period, for a pooled incidence density of 17.0 per 100 person-years (95% confidence interval [CI] = 14.68, 19.66). Incidence density declined, from a high of 30.8 per 100 person-years (95% CI = 21.3, 44.6) in 2003 to a low of 4.0 (95% CI = 1.3, 12.3) in 2009.

CONCLUSIONS

A decline in HCV incidence among Australian IDUs attending NSPs coincided with considerable expansion of harm reduction programs and a likely reduction in the number of IDUs, associated with significant changes in drug markets. Our results demonstrate the capacity of repeat cross-sectional serosurveillance to monitor trends in HCV incidence and provide a platform from which to assess the impact of prevention and treatment interventions.

Individual-level syringe coverage among Needle and Syringe Program attendees in Australia

BACKGROUND

Harm associated with injecting drug use is a significant public health issue and a major cause of morbidity and mortality, with global estimates of 3 million injectors infected with HIV and 8 million living with chronic hepatitis C virus (HCV) infection. Estimates of program coverage are widely used in the context of HIV prevention and are critical in determining the effectiveness of interventions such as Needle and Syringe Programs (NSPs).

METHODS

Data from a national cross-sectional study of NSP attendees in Australia were used to estimate individual-level syringe coverage as a proportion of monthly injections covered by a new syringe. Univariate and multivariate logistic regressions modelled associations between demographics, injecting risk, anti-HIV and HCV prevalence and syringe coverage. The median number of syringes retained per NSP attendee per annum was also estimated.

RESULTS

Twenty percent of participants had insufficient new syringes for all injections. Syringe reuse (including reuse of one's own syringe) was independently associated with syringe coverage of <100%. Conversely, procurement of syringes from an NSP was independently associated with syringe coverage ≥100%, with a greater protective effect occurring when NSP utilisation was combined with current engagement in opiate substitution therapy. The median number of syringes retained per participant per annum was 720, equivalent to 2 per day.

CONCLUSIONS

While Australian NSP attendees report high syringe coverage by international standards, prevention efforts could be scaled up. Syringe reuse was associated with syringe coverage of <100%, suggesting the utility of reuse as a proxy for individual-level syringe coverage.

Fifteen years of HIV surveillance among people who inject drugs: the Australian Needle and Syringe Program Survey 1995-2009

OBJECTIVES

Following bipartisan political support in Australia for the timely introduction of needle and syringe programs (NSPs), HIV prevalence among people who inject drugs (PWID) remains low. This study aimed to determine the correlates of HIV infection among PWID; and to examine these correlates over time.

DESIGN

Annual cross-sectional seroprevalence studies among attendees of sentinel NSP sites.

METHOD

Multiple logistic regressions conducted on aggregated, de-duplicated data from 1995 to 2009 to determine variables independently associated with HIV infection.

RESULTS

Data were available for 22 478 individual NSP attendees, equating to a mean annual response rate of 44% (range 38-60%). Two-thirds of participants were men, with a median age of 30 years, and a median of 10 years since first injection. Eighty-five percent identified as heterosexual, 10% as bisexual and 5% as homosexual. Serology was available for 21 248 participants, of whom 230 (1.1%) tested HIV antibody positive. Variables independently associated with antibody seropositivity were homosexual or bisexual identity; male sex; older age; older age at first injection; and survey participation between 1995 and 1997 rather than later periods.

CONCLUSIONS

Unlike settings in which evidence-based public health approaches to illicit drug policy are yet to be implemented, the epidemiology of HIV among NSP attendees mirrors that of Australia's general population, with the majority of exposures attributed to male-to-male sexual contact. This pattern has remained unchanged over 15 years despite significant variation in drug markets and patterns of drug use. NSPs also play a crucial role in this country's comprehensive HIV surveillance mechanisms.

Improving access to hard-to-reach services: a soft entry approach to drug and alcohol services for rural Australian Aboriginal communities

Australian Aboriginal communities are concerned about drug- and alcohol-related harms in their communities. There are a significantly higher proportion of substance problems experienced by Aboriginal Australians than non-Indigenous Australians. Ways to address these problems are limited by racial barriers to mainstream services, especially in the rural context. Soft entry was an approach designed to increase Aboriginal Australians' access to Drug & Alcohol (D&A) services. The approach was designed to put control over when and how D&A interventions were delivered in the hands of the community and individuals within it by giving them ready access to a human services worker with specialist knowledge. Quantitative and qualitative evaluation methods found that soft entry substantially increased the number of Aboriginal and non-Aboriginal women accessing drug and alcohol services. It fundamentally shifted the power relationship between counselors and community, providing opportunities to develop a non-stigmatizing trustful rapport to facilitate discussion of harmful substance use. The challenges for drug and alcohol counselors were the slow unpredictability of the approach and the need for highly skilled and responsive communication techniques. However, the factor most likely to improve access to services, once trust is developed, is regular and frequent attendance at the service delivery site.

Gender differences in hepatitis C antibody prevalence and risk behaviours amongst people who inject drugs in Australia 1998-2008

BACKGROUND

Global prevalence of hepatitis C virus (HCV) is estimated to be around 3% with approximately 170 million people affected. In Australia, and in many other resource rich countries, injecting drug use is the single most important risk factor for acquiring HCV, with around a third of diagnoses occurring in women. This study aims to assess gender differences in hepatitis C antibody prevalence and associated risk behaviours amongst a large sample of PWID in Australia.

METHODS

During a one to two week period in October, PWID attending selected NSP sites are invited to participate in the Australian NSP Survey. Between 1998 and 2008, approximately 16,000 individuals completed a self-administered questionnaire and provided a capillary blood sample for HIV and HCV antibody testing. We stratified our sample by time since onset of injecting and analysed the demographic characteristics, injecting behaviours and antibody test results to determine gender differences.

RESULTS

Women were found to be at increased risk of exposure to hepatitis C in all duration of injection categories except those injecting for 17 or more years. In the early years of injecting, women also reported higher rates of receptive sharing of needles and syringe and ancillary equipment when compared to men. Last injecting heroin, methadone or buprenorphine was significantly associated with HCV antibody prevalence amongst both males and females injecting for less than 5 years.

CONCLUSION

Findings indicate that women are at greater risk than men of HCV infection during the early years of injection through higher rates of receptive sharing of needles and syringes and/or ancillary equipment. Our results suggest that women who are new to injecting, and Indigenous women in particular, should be identified as priority populations when developing and implementing harm reduction strategies that target people who inject illicit drugs.

Can drug injectors be encouraged to adopt non-injecting routes of administration (NIROA) for drugs?

Drug use by injection can cause problems specific to this form of administration. Problems include an increased risk of drug overdose, drug dependence, the transmission of HIV, hepatitis B and hepatitis C and vein damage. Shifting drug injectors from injecting to another route of administration may minimize these problems. The aims of the study were to develop and trial an intervention to assist willing injecting drug users (IDUs) to shift to non-injecting routes of administration (NIROA) and to explore the acceptability and practicality of facilitating NIROA. IDUs were assessed and suitable subjects entered a cognitive behavioural trial consisting of five 1-hour sessions of individual therapy with a registered psychologist. Forty-two subjects were assessed (22 males and 20 females). Thirty subjects entered treatment. The mean age was 36 years. Twenty-one subjects were followed-up at 3 months and 10 subjects at 6 months. At 3 and 6 months, the proportion of subjects who had commenced using NIROA was 30% and 50%, respectively. This pilot study showed that it was possible to assist a minority of drug injectors to move from injecting to the non-injecting administration of drugs. However, many of these appeared to be already motivated to cease using drugs and adopting NIROA was one way of assisting this. Poor follow-up rate, lack of control group, questions about cost-effectiveness and the impact of market factors which possibly constrain shifting to NIROA suggest that further research is needed before it could be said that NIROA should be recommended as a viable harm reduction strategy in the Australian context.

Hepatitis C virus acquisition among injecting drug users: a cohort analysis of a national repeated cross-sectional survey of needle and syringe program attendees in Australia, 1995-2004

High hepatitis C virus (HCV) prevalence has been documented among many injecting drug user (IDU) populations worldwide; however, there is limited published data on trends in incidence of infection in these epidemics over time. To address this, we used a novel method of analyzing data collected via repeat, cross-sectional sero-surveys by injection initiation cohorts to investigate trends in HCV seropositivity among a population of needle and syringe program (NSP) attendees in Australia between 1995 and 2004, and thereby infer annual incidence trends. Injection initiation cohorts were defined by their time of entry into the IDU population. We also investigated the associations between HCV antibody seroprevalence and risk factor data, and trends in risk factor data over the decade. Approximately 20,000 NSP attendees participated in the study over the 10-year period. Within each injection initiation cohort, we found an increase in HCV prevalence over time, with prevalence appearing to reach saturation around 90%. There was little indication that the slopes of increase had changed with more recent initiation cohorts. While duration of injecting was most strongly associated with HCV seropositivity in this study, we also found that self-reported history of needle and syringe sharing and imprisonment were independently associated with higher HCV prevalence regardless of duration of injecting, with the exception of IDUs who have 15 or more years injecting experience. In this group, recent risk behavior had no relationship to prevalence. In summary, our findings suggest a persistent HCV epidemic despite significant harm reduction efforts in Australia since the mid-1980s, with HIV incidence effectively constant in successive initiation cohorts.

Estimating the size and dynamics of an injecting drug user population and implications for health service coverage: comparison of indirect prevalence estimation methods

AIMS

(i) To compare indirect estimation methods to obtain mean injecting drug use (IDU) prevalence for a confined geographic location; and (ii) to use these estimates to calculate IDU and injection coverage of a medically supervised injecting facility.

DESIGN

Multiple indirect prevalence estimation methods.

SETTING

Kings Cross, Sydney, Australia.

PARTICIPANTS

IDUs residing in Kings Cross area postcodes recorded in surveillance data of the Sydney Medically Supervised Injecting Centre (MSIC) between November 2001 and October 2002.

MEASUREMENTS

Two closed and one open capture-recapture (CRC) models (Poisson regression, truncated Poisson and Jolly-Seber, respectively) were fitted to the observed data. Multiplier estimates were derived from opioid overdose mortality data and a cross-sectional survey of needle and syringe programme attendees. MSIC client injection frequency and the number of needles and syringes distributed in the study area were used to estimate injection prevalence and injection coverage.

FINDINGS

From three convergent estimates, the mean estimated size of the IDU population aged 15-54 years was 1103 (range 877-1288), yielding a population prevalence of 3.6% (2.9-4.3%). Mean IDU coverage was 70.7% (range 59.1-86.7%) and the mean adjusted injection coverage was 8.8% (range 7.3-10.8%). Approximately 11.3% of the total IDU population were estimated to be new entrants to the population per month.

CONCLUSIONS

Credible local area IDU prevalence estimates using MSIC surveillance data were obtained. MSIC appears to achieve high coverage of the local IDU population, although only an estimated one in 10 injections occurs at MSIC. Future prevalence estimation efforts should incorporate open models to capture the dynamic nature of IDU populations.

Estimating the risk of blood donation associated with HIV risk behaviours

A blood donor questionnaire and declaration, with deferral of potential donors at a higher risk of blood-borne infections, was introduced in Australia in the mid-1980s to reduce the risk of donation of HIV-infected blood. However, the absolute risk of HIV transmission through blood donation from high-HIV-risk donors has not been estimated. This study presents a new method of assessing the risk posed to the blood supply by selected HIV risk behaviours. A model was developed to estimate the probability of blood donation during the window period for HIV infection. Five scenarios for blood donors were considered: (1) men who have sex with men (MSM), (2) men who have sex with women in Australia, (3) women who have sex with partners from countries with a high HIV prevalence, (4) men who have sex with commercial sex workers in Australia and (5) people injecting drugs used once in a year. Those estimated to be at highest risk of becoming infected and donating in the window period were MSM. Women who have sex with men from countries of high HIV prevalence are at greater risk than men who have sex with female sex workers from Australia. These three groups under current Australian guidelines are deferred from donating blood for 12 months. In Australia, a single episode of injecting drug use is associated with very low risk of HIV transmission. The model presented in this study can be used to assess the impact of selected individual risk behaviours on the safety of the blood supply.

Prevalence and predictors of injecting-related injury and disease among clients of Australia's needle and syringe programs

OBJECTIVE

To identify lifetime prevalence and predictors of self-reported injecting-related injuries and diseases (IRID) and/or injecting-related problems (IRP) among a national cross-sectional sample of injecting drug users.

METHODS

1,961 clients of 45 needle and syringe programs (NSPs) who participated in the 2006 Australian NSP Survey self-completed an item regarding lifetime experience of eight separate IRIDs and IRPs.

RESULTS

Sixty-nine per cent of participants reported a history of IRID/IRP, with a mean of 1.9 injuries/problems (range 0-8). Lifetime prevalence of specific injuries/problems ranged from problems finding a vein (43%) to endocarditis (4%). Factors independently associated with IRID/IRP included bisexual identity; daily or more frequent injecting; injection of pharmaceutical preparations; female gender; longer injecting history; and hepatitis C antibody-positive serostatus.

CONCLUSIONS

Consistent with existing literature, results suggest that vascular injury and localised infections are common among IDUs; and that treatment-seeking is often delayed until serious complications arise.

IMPLICATIONS

Findings support the imperative for co-ordinated and timely treatment and prevention activities to reduce the severity and burden of these prevalent injecting outcomes.

Hepatitis C virus incidence among injecting drug users on opioid replacement therapy

OBJECTIVE

To determine hepatitis C virus (HCV) incidence among injecting drug users (IDUs) receiving opioid replacement therapy (ORT).

METHODS

A retrospective cohort study was established in a primary care drug dependency treatment clinic. The cohort included all IDUs who commenced ORT after January 1996 with an initial anti-HCV antibody negative result and repeat testing prior to July 2003. HCV incidence was estimated for all subjects, with further comparison among those with continuous versus interrupted ORT.

RESULTS

Fifty-four subjects were initially HCV antibody negative and had repeat testing. Five cases of HCV antibody seroconversion occurred during a total follow-up period of 131.1 person years (py), an incidence of 3.8/100 py (95% CI 1.2-8.9/ 100 py). Four seroconversions occurred in the subgroup with interrupted ORT (n=20), an incidence of 7.4/100 py (95% CI 2.0-18.9/100 py), compared with one seroconversion in the subgroup with continuous ORT (n=34), an incidence of 1.3/100 py (95% CI 0.03-7.3/100 py).

CONCLUSIONS

HCV incidence among IDUs receiving ORT in our clinic was relatively low. Those IDUs without interruptions to their treatment appeared to be at particularly low risk of HCV infection. These findings support the role of ORT in HCV prevention for IDUs.

Self reported risk behaviour among injecting drug users: Self versus assisted questionnaire completion

The current study aimed to compare self-reported injecting and sexual risk behaviour among Needle and Syringe Program (NSP) attendees who self-completed a questionnaire to that of those who received assistance in completing the questionnaire. Information on demographic, injecting and sexual risk behaviour was collected via a self-completed questionnaire for an annual cross-sectional survey of injecting drug users (IDUs) recruited from sentinel NSPs around Australia. Assistance was provided when necessary and recorded. Of 2,035 participants, 1,452 (71%) reported completing the questionnaire without assistance. Being male and nominating a language other than English spoken at home was independently associated with receiving assistance with questionnaire completion. Participants who reported heroin as the drug last injected were also more likely to receive assistance. Multivariate analyses revealed those who received assistance with questionnaire completion were less likely to report re-using a syringe after someone else and less likely to report sex work in the past month. The current findings suggest self-completion of risk behaviour questionnaires should be considered as an alternative to interviewer administered questionnaires to maximise accuracy of self-reports.

Diffusion of the D.A.R.E and syringe exchange programs

We examined the diffusion of the D.A.R.E program to reduce use of illicit drugs among school-aged children and youths and the diffusion of syringe exchange programs to reduce HIV transmission among injection drug users. The D.A.R.E program was diffused widely in the United States despite a lack of evidence for its effectiveness; there has been limited diffusion of syringe exchange in the United States, despite extensive scientific evidence for its effectiveness. Multiple possible associations between diffusion and evidence of effectiveness exist, from widespread diffusion without evidence of effectiveness to limited diffusion with strong evidence of effectiveness. The decision theory concepts of framing and loss aversion may be useful for further research on the diffusion of public health innovations.

Transition to injection and sharing of needles/syringes: potential for HIV transmission among heroin users in Chengdu, China

This cross-sectional survey interviewed heroin injectors admitted in three detoxification centres from August 2003 to June 2004 in Chengdu City, China. Logistic regression and survival analysis were performed to identify factors associated with sharing of needles/syringes and time from initiation of heroin to adoption of injection, respectively. Out of 266 subjects studied, 206 (77.44%) were males, 103 (38.72%) never shared injecting materials, 113 (42.48%) were non-Chengdu residents and 9 (3.38%) belonged to ethnic minorities. Those with short history of heroin injection (P<0.05) and those belonged to ethnic minorities (P<0.05) were more likely to share injecting materials. Only age, ethnicity and duration of heroin use were associated with time to first injection. Median time to injection was 6 months for those who used heroin for the duration up to 1 year and 21 months for those who used heroin for 2-5 years. The study suggests that there is early initiation of injection and sharing of injecting materials is high among heroin users, a major risk for HIV transmission. Ethnic minorities have been identified to be the most risky group, which needs further attention.

A longitudinal study of syringe acquisition by Puerto Rican injection drug users in New York and Puerto Rico: implications for syringe exchange and distribution programs

Increasing access to sterile syringes and new drug preparation materials is an effective means of reducing HIV transmission among injection drug users (IDUs), and a fundamental component of harm reduction ideology. The purpose of this study is to examine changes during a three-year period in syringe acquisition by street-recruited Puerto Rican IDUs characterized by frequent drug injection and high HIV seroprevalence. At baseline (1998-1999) and 36-month follow-up, 103 IDUs recruited in East Harlem, New York (NY), and 135 from Bayamón, Puerto Rico (PR) were surveyed about syringe sources and HIV risk behaviors in the prior 30 days. A majority of participants in both sites were male (NY 78.6%, PR 84.4%), were born in Puerto Rico (NY 59.2%, PR 87.4%), and had not completed high school (NY 56.3%, PR 51.9%). Compared to PR IDUs at follow-up, NY IDUs injected less (3.4 vs. 7.0 times/day, p < .001), and re-used syringes less (3.1 vs. 8.0 times, p < .001). Between baseline and follow-up, in NY the proportion of syringes from syringe exchange programs (SEPs) increased from 54.2% to 72.9% (p = .001); syringes from pharmacies did not increase significantly (0.2% to 2.5%, p = .095). In PR, the proportions of syringes from major sources did not change significantly: private sellers (50.9% to 50.9%, p = .996); pharmacies (18.6% to 19.0%, p = .867); SEP (12.8% to 14.4%, p = .585). The study indicates that NY SEPs became more dominant, while NY pharmacies remained a minor source even though a law enacted in 2001 legalized syringe purchases without prescription. Private sellers in PR remained the dominant and most expensive source. The only source of free syringes, the SEP, permitted more syringes to be exchanged but the increase was not statistically significant. Implications for syringe exchange and distribution programs are discussed.

Injecting nation: achieving control of hepatitis C in Australia

Since Australia banned heroin in 1953 consumption of illicit drugs, deaths, crime and corruption related to drugs have steadily increased. Injecting drug use (IDU) in Australia is now a significant public health problem linked each year to approximately 500 overdose deaths and more than 6000 hepatitis C infections. At least 85% of prevalent and incident hepatitis C cases in Australia are injecting drug users (IDUs) with annual incidence estimated at 15%. Although poorly documented, increasing numbers of patients with end-stage liver disease from hepatitis C now appear to present in Australia. This reflects a heroin-injecting epidemic commencing a quarter of a century ago, the close association between drug injecting and hepatitis C and the long delay between hepatitis C infection and complications. The overall health and economic burden of hepatitis C may soon exceed HIV. Control is far more difficult to achieve for hepatitis C than HIV because of much higher baseline prevalence levels and far greater infectiousness by blood to blood spread. Transmission appears to follow minimal breaches of infection control guidelines. Hepatitis C has not yet become a priority public health issue in Australia. No national prevention strategy has been proposed. Prevention strategies (such as needle exchange or methadone) which controlled HIV among IDUs should be expanded, with the expectation of some useful reduction of spread but without achieving control of hepatitis C. Other options for control must be considered. Eradicating illicit drug use in Australia is unachievable. Virtually eradicating injecting drug use by facilitating a switch to non-injecting routes of administration (NIROA) is achievable (although difficult) and this could control hepatitis C. NIROA will have the probable additional benefit of reducing drug overdose deaths. NIROA has begun recently to replace injecting in several countries without government intervention. Powerful cultural, pharmacological and economic factors strongly reinforce drug injecting. Economic impediments to NIROA could be reduced by drug policy reform. Facilitating a switch to NIROA carries some risk of increased discrimination directed against an already marginalized population. A major obstacle to harm reduction is the common assumption that any relaxation of drug policy invariably leads to increased consumption. Switching the predominant route of administration of illicit drugs from IDU to NIROA should be the major focus of national efforts to control hepatitis C and overdose deaths in Australia.

The impact of changes to heroin supply on blood-borne virus notifications and injecting related harms in New South Wales, Australia

Background

In early 2001 Australia experienced a sudden and unexpected disruption to heroin availability, know as the 'heroin shortage'. This 'shortage has been linked to a decrease in needle and syringe output and therefore possibly a reduction in injecting drug use. We aimed to examine changes, if any, in blood-borne viral infections and presentations for injecting related problems related to injecting drug use following the reduction heroin availability in Australia, in the context of widespread harm reduction measures.

Methods

Time series analysis of State level databases on HIV, hepatitis B, hepatitis C notifications and hospital and emergency department data. Examination of changes in HIV, hepatitis B, hepatitis C notifications and hospital and emergency department admissions for injection-related problems following the onset of the heroin shortage; non-parametric curve-fitting of number of hepatitis C notifications among those aged 15–19 years.

Results

There were no changes observed in hospital visits for injection-related problems. There was no change related to the onset heroin shortage in the number of hepatitis C notifications among persons aged 15–19 years, but HCV notifications have subsequently decreased in this group. No change occurred in HIV and hepatitis B notifications.

Conclusion

A marked reduction in heroin supply resulted in no increase in injection-related harm at the community level. However, a delayed decrease in HCV notifications among young people may be related. These changes occurred in a setting with widespread, publicly funded harm reduction initiatives.

HIV prevalence among injecting drug users in England and Wales 1990 to 2003: evidence for increased transmission in recent years

OBJECTIVE

To describe trends in HIV prevalence among injecting drug users in England and Wales between 1990 and 2003.

METHODS

Analysis of surveillance data from voluntary unlinked anonymous cross-sectional surveys collecting oral fluid samples and behavioural information from injecting drug users recruited from both drug agency (n = 24,304) and community settings (n = 3628).

RESULTS

HIV prevalence in England and Wales declined from 5.9% in 1990 to 0.6% in 1996 and then remained stable until 1999, after which it increased to 1.4% in 2003. Few HIV infections were detected among short-term injectors between 1994 and 1999, but in recent years prevalence among this group has increased. Other factors associated with higher odds of HIV infection were being recruited in London and from community settings, and ever having had a voluntary confidential HIV test. Incidence estimated through a force of infection model was 2.8% per annum among those injecting for less than a year in London between 1998 and 2003.

CONCLUSIONS

These data suggest that incidence and prevalence of HIV may have increased, whereas other indicators suggest an increase in risk behaviour. It is critical that harm reduction measures are reinvigorated, and evolve in response to changes in drug use risk behaviours and policy.

HIV/AIDS surveillance systems in Australia

We review the HIV/AIDS reporting protocols in Australia, and describe the technical components of surveillance and its guiding principles, including a strict adherence to confidentiality at all levels. The majority of AIDS diagnoses in Australia have occurred in men who acquired HIV infection through male-to-male sex. The annual incidence of AIDS peaked in 1994, and then declined sharply over the subsequent 4 years. Advances in treatment effectiveness have focused attention on ensuring that people with HIV infection have access to optimal therapy, and emphasized the role of AIDS case reports as indicators of treatment failure. Analyses of the date of HIV diagnosis in people with AIDS have been used as indicators and predictors of undiagnosed HIV infection in the population. Australia's linkage of program funding to AIDS case counts provides an incentive for both health departments and community-based organizations to actively support AIDS surveillance activities. The challenge for surveillance is to maintain vigilance for shifts in HIV infection rates, or in behavior patterns that may be related to transmission.

Recent trends in the HIV epidemic among injecting drug users in Northern Italy, 1993-1999

OBJECTIVE

To monitor and describe the time trends of the HIV epidemic among intravenous drug users (IDU) attending drug dependence treatment centres (DDTC) in Northern Italy.

DESIGN

A cohort of all seronegative IDU attending DDTC in Lombardy between 1993 and 1999; all had been tested for HIV at least twice. Periodic sample interview surveys were done to assess risk behaviours.

METHODS

The incidence rates of HIV infection were calculated using the person-year (PY) method and expressed as the number of cases per 1000 PY at risk. Background HIV prevalence was calculated by dividing the number of positive cases by the total number of IDU tested at all DDTC in Lombardy.

RESULTS

Between 1993 and 1999, 135 seroconversions occurred in 7945 subjects followed for 19 671 PY, yielding an incidence rate of 6.9/1000 PY. Ninety seroconversions occurred among the 6563 males and 45 seroconversions among 1382 females (incidence rates 5.5 and 14.0, respectively). Among the males, the incidence of HIV was 4.5 in those aged less than 25 years and 5.8 in those aged 25 years or more. Among the females, the corresponding figures were 21.1 and 10.3. HIV prevalence decreased over time, and it was higher among females. Sexual behaviours at risk were more common among females.

CONCLUSIONS

The incidence of HIV infection among IDU in Northern Italy was stable between 1993 and 1999. The higher incidence and prevalence among females and the different prevalence of risk behaviours between genders suggest an increasing role of heterosexual transmission.

Documented prevalence of HIV and hepatitis C infection in patients with penetrating trauma

BACKGROUND

Trauma patients infected with human immunodeficiency virus (HIV) or hepatitis C (HCV) pose specific problems to health-care workers due to the risk of exposure to these agents in blood and other body fluids. Studies of patients with penetrating trauma in the USA have shown a higher prevalence of HIV and HCV infection than the general population. No studies have examined the prevalence of these infections in Australian trauma patients.

METHODS

The medical records of all patients presenting to St Vincent's Hospital, Sydney, from January 1994 to December 1998, with a stab wound to the neck, chest or abdomen, or with a gunshot wound to any anatomical site, were retrospectively reviewed. The number of patients with a history of HIV or HCV infection, or with risk factors for these such as male-to-male sexual intercourse and intravenous drug use, were recorded.

RESULTS

The medical records of 148 patients with stab wounds to the neck, chest or abdomen, or with gunshot wounds were examined. Risk factors for HIV or HCV infection were recorded in 31 patients (21%). Two patients (1.3%) had a history of HIV infection and a further eight patients (5.4%) were known to have HCV.

CONCLUSIONS

There was a high prevalence of risk factors for HIV and HCV in patients with major penetrating wounds at St Vincent's Hospital. The prevalence of documented HIV and HCV infection was subsequently greater than that expected in the general population, highlighting the risks to health-care workers managing these patients.

Syringe availability as HIV prevention: a review of modalities

This review examines recent research into modalities for improving access to sterile syringes for injection drug users (IDUs) as a means to reduce human immunodeficiency virus (HIV) transmission. English language studies with empirical data were collected through Uncover reports and MedLine searches from 1998 to 2000. Although syringe-exchange programs are the most established and well-evaluated means of improving access to sterile syringes, research on alternative modalities-such as pharmacy sale, injector-specific packs, mass distribution, and vending machines-and on coverage of special populations suggests the need to pursue multiple avenues of increasing syringe availability simultaneously and, in particular, to explore modalities other than syringe-exchange programs when HIV incidence is under control. The impacts on HIV transmission of cocaine injection and sex with IDUs need to be explored further. Finally, any evidence of declining hepatitis C incidence among young IDUs might serve as a surrogate for a sharp drop in injection-related HIV risk behaviors in that population.

Women Injection Drug Users Who Have Sex with Women Exhibit Increased HIV Infection and Risk Behaviors

This article is a comprehensive review of published research on HIV seroprevalence and HIV-related risk behaviors among women injection drug users (IDUs) who have sex with women (WSW). At least 14 studies since the late 1980s converge into a consistent pattern: compared to other IDUs, WSW IDUs report higher levels of HIV-related risk behaviors and in many cases exhibit higher rates of HIV seroconversion or seroprevalence. Data from these and additional studies also indicate that large numbers of women IDUs are WSWs. Since information regarding WSW IDUs are widely collected but infrequently analyzed and reported, we suggest promising research and analysis strategies for exploring the meaning behind this pattern of increased vulnerability to HIV. Finally, we assert that enough is currently known to warrant significant investment in targeted prevention and intervention programs to address the critical HIV-related needs of lesbian, bisexual, and other WSW IDUs.

Structural interventions to reduce HIV transmission among injecting drug users

OBJECTIVE

To review current knowledge of 'structural' interventions to reduce HIV transmission among injecting drug users. Structural interventions are defined as programs or policies that change the environments in which risk behavior occurs, without attempting to change knowledge, attitudes or social interaction patterns of the persons at risk. Structural interventions may either facilitate enactment of existing motives to avoid HIV transmission or make enacting risk behavior more difficult.

METHODS

Nonquantitative literature review.

RESULTS AND CONCLUSIONS

Preventing HIV infection among injecting drug users must be considered within the context of the continuing global spread of psychoactive drug use, and injecting drug use in particular. Some policies that are designed to reduce drug use may tend to increase HIV transmission among persons who do inject drugs. Evaluation of structural interventions can be difficult, as populations of drug users are usually the relevant unit of analysis. Typically, pre versus post comparisons must be used, hopefully with multiple pre and post data points. Structural interventions are often associated with 'large effects', increasing confidence that the intervention is the cause of the reduction in HIV-risk behavior. Increasing the availability of sterile injection equipment, through pharmacy sales or syringe exchange or both, is the most common and best-studied structural intervention for injecting drug users. The studies to date indicate that this usually, but not always, leads to large reductions in HIV-risk behavior. Involving drug users in the design and implementation of HIV-prevention programs can be considered a 'meta-structural' intervention that should lead to programs with increased effectiveness.

Hitting up in the top end: characteristics of needle exchange clients in Darwin

OBJECTIVE

Little is known about injecting drug use (IDU) and blood-borne viral (BBV) infection in rural Australia.

METHOD

These repeat cross-sectional studies were conducted during a two-week period in July and October-November 1998 at the Darwin needle exchange, with 129 and 121 respondents respectively.

RESULTS

The commonest drug of choice was heroin, but the commonest drug injected was morphine. Self-reported sharing of needles and syringes was uncommon. Self-reported serostatus for HIV was high (8% and 11.4% respectively), but seemingly mostly associated with sexual rather than IDU risk; for hepatitis C (HCV) status, these were 54% and 37%. Among IDUs of Aboriginal or Torres Strait Islander (ATSI) background, who made up 14% of the first round respondents, patterns of IDU and of BBV infection were the same as among non-ATSI respondents.

CONCLUSIONS

These surveys reveal patterns of IDU in Darwin that have both similarities and differences with those in the major urban centres in Australia. In the absence of a comprehensive methadone maintenance program, many participate in a more or less informal morphine substitution program. HIV is present among these IDUs, and the risks of further sexual transmission may be high.

IMPLICATIONS

These surveys confirm the presence among injecting drug users in Darwin of HIV, HBV and HCV, and of the risk for further spread of these viruses. Control of blood-borne virus transmission among IDUs requires an even greater commitment to abolishing sharing of needles and syringes, and therefore continued support and enhancement of needle and syringe availability.

Hepatitis C virus antibody prevalence among injecting drug users at selected needle and syringe programs in Australia, 1995-1997. Collaboration of Australian NSPs

OBJECTIVES

To describe point prevalence of HCV antibody and relevant risk behaviour among people who inject drugs and who attended selected needle and syringe programs throughout Australia in 1995, 1996 and 1997.

DESIGN AND SETTING

Repeated cross-sectional surveys of one week's duration were carried out in 21, 20 and 23 needle and syringe program sites throughout Australia in 1995, 1996 and 1997, respectively.

PARTICIPANTS

All clients attending participating sites during the designated survey week were asked to complete a self-administered questionnaire and provide a finger-prick blood sample for HCV antibody testing.

MAIN OUTCOME MEASURES

Prevalence of HCV antibody.

RESULTS

Survey response was 41% (n = 979) in 1995, 51% (n = 1463) in 1996 and 48% (n = 1699) in 1997. HCV prevalence declined significantly from 63% in 1995 to 51% in 1996 and 50% in 1997 (P < 0.001). Among respondents who reported injecting for less than three years, prevalence declined from 22% in 1995 to 13% in 1996 and 1997 (P < 0.001). Reported use of needles and syringes after someone else in the previous month declined from 31% in 1995 and 28% in 1996 to 15% in 1997 (P < 0.001).

CONCLUSIONS

Despite an apparent decline in HCV prevalence, carriage rates of HCV antibody remain high.