Representativeness of Injecting Drug Users Who Participate in HIV Surveillance: Results From Australia's Needle and Syringe Program Survey

Utilising Integrated Bio-behavioural Surveillance (IBBS) to investigate declining hepatitis C antibody prevalence among people who inject drugs in the Australian Needle and Syringe Program Survey

BACKGROUND

Prevalence of hepatitis C virus (HCV) antibody (Ab) on dried blood spot (DBS) samples in the Australian Needle and Syringe Program Survey (ANSPS) decreased nationally from 57% in 2015 to 32% in 2022. We aimed to investigate potential explanations for this decline.

METHODS

Changes in DBS HCV Ab prevalence were investigated by redefining positive cases as those with those with either a positive HCV Ab test result or a self-reported history of ever having HCV treatment (modified prevalence), examining HCV Ab prevalence by birth and age cohorts, and assessing trends in key risk behaviours.

RESULTS

Overall prevalence of DBS HCV Ab declined rapidly and significantly from 57% in 2015 to 32% in 2022 (p<0.001) however modified HCV Ab prevalence remained stable over time (85% and 88% in 2015 and 2022, respectively, p=0.357). The proportion of participants with negative HCV Ab and self-reported HCV infection increased from 20% in 1995 to 40% in 2022 (p<0.001) and the proportion with negative HCV Ab and lifetime HCV treatment increased from 3% in 1999 to 67% in 2022 (p<0.001). We also observed a decreasing trend in DBS HCV Ab prevalence in all birth and age cohorts with a noticeable acceleration in the decline commensurate with the advent of HCV DAA treatment. A long-term decreasing trend was also observed for key risk behaviours (p<0.001) however the short-term trend was not significant for recent receptive syringe sharing.

CONCLUSION

The temporal decline in HCV Ab prevalence appears related to reduced sensitivity of DBS HCV Ab detection with viral clearance following treatment. Since 2016, HCV treatment uptake has increased markedly including among people who inject drugs. In this context, continuing to monitor HCV Ab prevalence by DBS testing is problematic, with a shift to surveillance of active infection the most relevant to guide policy and practice in this setting.

Uptake of COVID-19 vaccination among people who inject drugs

Background

People who inject drugs (PWID) may be at elevated risk of adverse outcomes from SARS-CoV-2 infection; however, data on COVID-19 vaccine uptake among PWID are scarce. This study aimed to determine COVID-19 vaccine uptake among PWID, identify factors associated with sub-optimal uptake, and compare uptake to the general population.

Methods

The Australian Needle Syringe Program Survey is an annual sentinel surveillance project, comprising a self-completed questionnaire and provision of a dried blood sample for HIV and HCV testing. In 2021, respondents provided information on their COVID-19 vaccination status. Multivariate logistic regression models identified correlates of vaccine uptake.

Results

Among 1166 respondents, 49% had been vaccinated and in most states and territories, vaccine uptake was significantly lower than among the general population. Independent predictors of vaccine uptake were longer duration of vaccine eligibility (AOR 3.42, 95% CI 2.65, 4.41); prior SARS-CoV-2 diagnostic testing (AOR 2.90, 95% CI 2.22, 3.79); injection of opioids (AOR 1.91, 95% CI 1.20, 3.05); and current opioid agonist therapy (AOR 1.70, 95% CI 1.23, 2.33). Women (AOR 0.70, 95% CI 0.54, 0.92) and those who reported daily or more frequent injection (AOR 0.75, 95% CI 0.57, 1.00) were significantly less likely to be vaccinated.

Conclusions

In most Australian states and territories, uptake of COVID-19 vaccine among PWID lagged uptake among the general population. Increased efforts are required to ensure PWID have equitable access to vaccination. Vaccination programmes within harm reduction services and via outreach, coupled with increased support for peers to act as vaccine champions, are likely to reduce barriers and improve COVID-19 vaccine uptake in this population.

Prevalence and correlates of multiple non-fatal opioid overdoses among people who inject drugs who utilise needle syringe programs in Australia

BACKGROUND

Non-fatal overdose (NFOD) is a major cause of morbidity among people who inject drugs (PWID) and multiple NFOD is associated with increased risk of fatal overdose. Despite this, few studies have examined the prevalence and correlates of drug-specific multiple NFOD. The current study aimed to determine the prevalence and correlates of recent multiple non-fatal opioid overdose (NFOOD) among PWID who access needle syringe programs (NSPs) in Australia.

METHODS

The Australian Needle and Syringe Program Survey is conducted annually and was conducted at 46 sites across Australia in 2019. Participation involves completion of a self-administered questionnaire and a capillary dried blood spot for HIV and hepatitis C virus testing. In 2019, respondents who reported a minimum of one NFOOD in the previous 12 months (recent NFOOD) were asked to complete supplementary questions regarding their last NFOOD. Bivariate and multivariate logistic regression were used to determine factors independently associated with multiple recent NFOOD.

RESULTS

A total of 222 respondents reported recent NFOOD. Respondents were predominantly male (59%), one third (39%) were aged less than 39 years and 73% reported last injecting heroin at their last NFOOD. One in two respondents (48%, n = 107) reported multiple opioid overdoses (median 3, interquartile range 2-5). The odds of reporting multiple NFOOD were higher among respondents who reported injecting in a public location at their last NFOOD (adjusted odds ratio [AOR] 2.10, 95% CI 1.14-3.90, p = 0.018) and benzodiazepine use in the 12 h prior to NFOOD (AOR 2.74, 95% CI 1.50-4.99, p = 0.001).

CONCLUSIONS

Multiple NFOOD was prevalent among PWID who utilised NSPs who reported recent NFOOD. Public injecting and benzodiazepine use were associated with increased risk of multiple NFOOD, and there is a need for interventions specifically targeting PWID who report these high risk injecting practices.

Incidence and factors associated with discontinuation of opioid agonist therapy among people who inject drugs in Australia

AIMS

To estimate incidence and predictors of opioid agonist therapy (OAT) discontinuation in a national cohort of people who inject drugs (PWID).

DESIGN AND SETTING

Annually repeated cross-sectional serosurveillance among PWID attending ~50 needle-syringe programmes across Australia.

PARTICIPANTS

Between 1995 and 2018, 2651 PWID who reported current OAT and had subsequent survey participation completed 6739 surveys. Respondents were followed over 11 984 person-years of observation (PYO). Respondents were predominantly male (60%), and the median age was 34 years. Heroin was the most commonly reported drug last injected (46%), and methadone was the most commonly prescribed OAT (77%).

MEASUREMENTS

The primary outcome was discontinuation of OAT (methadone, buprenorphine or buprenorphine-naloxone). Among respondents who reported current OAT, those who did not report current OAT in all subsequent records were defined as discontinued, and those with current OAT at all subsequent records were defined as retained. Predictors of discontinuation included self-reported demographic (sex, location, Indigenous status) and drug use characteristics (drug last injected, frequency of injection).

FINDINGS

Just fewer than one-third of respondents (29%) reported an OAT discontinuation event. The crude discontinuation rate was 6.3 [95% confidence intervals (CI) = 5.9-6.8] per 100 PYO. Discontinuation was significantly higher among respondents who reported last injecting pharmaceutical opioids [adjusted hazard ratio (aHR) = 1.75, 95% CI = 1.41-2.17, P < 0.001], being prescribed buprenorphine (aHR = 1.44, 95% CI = 1.18-1.76, P = 0.001) or buprenorphine-naloxone (aHR = 1.68, 95% CI = 1.20-2.34, P = 0.002), daily or more frequent injection (aHR = 1.51, 95% CI = 1.23-1.85, P < 0.001), recent public injecting (aHR = 1.37, 95% CI = 1.17-1.60, P < 0.001), incarceration in the previous 12 months (aHR = 1.31, 95% CI = 1.05-1.64, P = 0.017), recent receptive syringe or injection equipment sharing (aHR = 1.28, 95% CI = 1.10-1.48, P = 0.001) and male sex (aHR = 1.27, 95% CI = 1.09-1.47, P = 0.002).

CONCLUSION

People who inject drugs attending needle-syringe programmes in Australia appear to be significantly more likely to discontinue opioid agonist treatment if they were prescribed buprenorphine or buprenorphine-naloxone compared with methadone, are male or report injection risk behaviours and recent incarceration.

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.

Are there missed opportunities for vaccinating against hepatitis B among people who inject drugs in the UK?

Sustaining the impact of hepatitis B virus (HBV) vaccination on incidence and prevalence of HBV infection requires increasing and maintaining the uptake of vaccine among those at risk. In recent years, the level of vaccine uptake among people who inject drugs (PWID) in the UK has levelled-off. Data (2015–2016) from the national unlinked-anonymous monitoring survey of PWID, an annual survey that collects data from PWID across England, Wales and Northern Ireland, were used to examine HBV vaccine uptake. Data from participants who had injected drugs during the previous year were used to investigate sources of hepatitis B vaccine doses as well as factors associated with vaccine uptake. Among the 3175 anti-HBc-negative participants, 3138 (99%) reported their vaccination status; 23% (714) reported no vaccine uptake. Among those not vaccinated, 447 (63%) reported being sexually active and 116 (16%) reported sharing needles and syringes. Majority of those not vaccinated reported accessing services in the previous year that could have provided hepatitis B vaccine doses. These missed opportunities for vaccinating of PWID indicate a need for additional targeted interventions.

Association between rapid utilisation of direct hepatitis C antivirals and decline in the prevalence of viremia among people who inject drugs in Australia

BACKGROUND & AIMS

The World Health Organization (WHO) established targets to eliminate hepatitis C virus (HCV) infection as a public health threat by 2030. Evidence that HCV treatment can lower viraemic prevalence among people who inject drugs (PWID) is limited. Broad accessibility of direct-acting antiviral (DAA) therapy in Australia, since March 2016, provides an opportunity to assess the efficacy of these treatments at a population level in a real-world setting.

METHODS

Data from Australia's annual bio-behavioural surveillance examined treatment uptake and estimated viraemic prevalence among PWID attending needle syringe programs nationally between 2015 and 2017. Multivariate logistic regression identified variables independently associated with HCV treatment among those considered eligible (anti-HCV positive excluding HCV RNA negative with no self-reported history of HCV treatment) in 2017.

RESULTS

Annual samples ranged from 1,995-2,380 PWID. Anti-HCV prevalence declined from 57% (2015) to 49% (2017, χ²p trend <0.001), with 40-56% of anti-HCV positive respondents providing sufficient sample for HCV RNA testing. Between 2015 and 2017, treatment uptake among those eligible increased from 10% to 41% (χ²p trend <0.001) and viraemic prevalence among the overall sample declined from 43% to 25% (χ²p trend <0.001). In multivariable analysis, older age (≥50 years adjusted odds ratio [aOR] 1.82; 95% CI 1.09-3.06;p = 0.023 and 44-49 years aOR 1.75; 95% CI 1.03-3.00;p = 0.038 vs. ≤37 years) and history of opioid substitution therapy (aOR 2.06; 95% CI 1.30-3.26; p = 0.002) were independently associated with treatment.

CONCLUSIONS

This study confirms PWID are willing to initiate treatment when HCV DAA therapy is available and provides population-level evidence of a decline in viraemic prevalence among people most at risk of ongoing HCV transmission. Scaled up surveillance and monitoring are required to evaluate progress toward WHO HCV elimination goals.

LAY SUMMARY

The World Health Organization's goal to reduce hepatitis C virus incidence by 80% will be difficult to achieve without widespread scale up and a corresponding reduction in viraemic prevalence among those most at risk of onward transmission. Our results indicate that a population-level reduction in viraemic prevalence is achievable through high levels of treatment and cure among people who inject drugs.

Intravenous fentanyl use among people who inject drugs in Australia

INTRODUCTION AND AIMS

There is a current epidemic of pharmaceutical opioid (PO) misuse, particularly fentanyl and fentanyl analogues, globally. Fentanyl is a highly potent synthetic opioid with rapid onset and significantly higher risk of overdose compared with other opioids. Contexts and correlates of fentanyl use among people who inject drugs (PWID) in Australia are under-researched.

DESIGN AND METHODS

The Australian Needle Syringe Program Survey is conducted annually. Consenting PWID complete a self-administered questionnaire and provide a capillary dried blood spot for human immunodeficiency virus and hepatitis C virus antibody testing. Bivariate and multivariate logistic regressions determined correlates of recent (last 6 months) fentanyl injection in 2014.

RESULTS

Recent fentanyl injection was reported by 8% (n = 193) of the total sample. Among the 848 PWID who recently injected POs, 23% injected fentanyl. Compared with PO injectors who had not injected fentanyl, those who had injected fentanyl were significantly more likely to identify as Indigenous Australian [adjusted odds ratio (AOR) 1.61; 95% confidence interval (CI) 1.04, 2.51; P = 0.034], inject daily or more frequently (AOR 1.92; 95% CI 1.30, 2.83; P = 0.005), inject in public (AOR 1.43; 95% CI 1.01, 2.02; P = 0.042) and to have overdosed in the past year (AOR 2.16; 95% CI 1.48, 3.13; P < 0.001), but were significantly less likely to receptively share syringes (AOR 0.56; 95% CI 0.36, 0.87; P = 0.010).

DISCUSSION AND CONCLUSIONS

Fentanyl injectors in Australia are significantly more likely to identify as Indigenous, report frequent injection, inject in public and experience overdose. Increased access to harm reduction interventions, including naloxone distribution, wheel filters and supervised injection facilities, are likely to benefit this population.

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.

Is the recent emergence of mephedrone injecting in the United Kingdom associated with elevated risk behaviours and blood borne virus infection?

The recent, and rapid, emergence of injection of the short-acting stimulant mephedrone (4-methylmethcathione) has resulted in concerns about increased infection risks among people who inject drugs (PWID). Data from the bio-behavioural surveillance of PWID in the United Kingdom were analysed to examine the impact of mephedrone injection on infections among PWID. During the year preceding the survey, 8.0% of PWID (163/2,047) had injected mephedrone. In multivariable analyses, those injecting mephedrone were younger, less likely to have injected opiates, and more likely to have injected cocaine or amphetamines, used needle/syringe programmes or sexual health clinics, been recruited in Wales and Northern Ireland or shared needles/syringes. There were no differences in sexual risks. Those injecting mephedrone more often had hepatitis C antibodies (adjusted odds ratio (AOR) = 1.51; 95% confidence interval (CI): 1.08-2.12), human immunodeficiency virus (AOR = 5.43; 95% CI: 1.90-15.5) and overdosed (AOR = 1.70; 95% CI: 1.12-2.57). There were no differences in the frequency of injecting site infections or prevalence of hepatitis B. The elevated levels of risk and infections are a concern considering its recent emergence. Mephedrone injection may currently be focused among higher-risk or more vulnerable groups. Targeted responses are needed to prevent an increase in harm.

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.

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.

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.

Disproportionate impact of combination antiretroviral therapy on AIDS incidence in Australia: results from a modified back-projection model

The objective of the current study is to describe the impact of Combination antiretroviral therapy (cART) on trends in AIDS incidence over time for selected population groups in Australia, specifically, men who have sex with men (MSM) and injecting drug users (IDUs). A modified back-projection modeling technique was used to predict the number of AIDS diagnoses without cART based on Australia's HIV/AIDS surveillance system database. Modelled estimates indicate that since 1996, the effective cART has reduced overall AIDS cases by ~70 and ~10% among MSM and IDUs respectively. The predicted reduction in AIDS cases among IDUs aged less than 40 years was 36% while there was no reduction predicted for those aged 40 years or older. The impact of cART on AIDS diagnoses has been modest among IDUs. Late presentation, poor access to health services and barriers to uptake of cART may account for the divergence between these population groups.

Developing and validating a scoring tool for identifying people who inject drugs at increased risk of hepatitis C virus infection

Objectives To develop and validate a scoring tool based on demographic and injecting risk behaviours to identify those who require additional, non-routine serological screening for hepatitis C virus (HCV) by assessing their personal risk. Design Cross-sectional and prospective cohorts. Setting People who inject drugs (PWID) and attended Needle and Syringe Programs (NSP) in Australia during the period from 1998 to 2008. Participants Cross-sectional data included 16 127 PWID who attended NSP in Australia. Prospective data included 215 HCV-negative PWID who were recruited through street-based outreach, methadone clinics in Australia. Primary and secondary outcome measures HCV seroprevalence in the cross-sectional and HCV seroconversions in the prospective data sets. Results Current study included 16 127 PWID who attended NSP in Australia. Type of drug last injected, frequency and duration of injecting, sharing needles and syringes or other injecting equipment and imprisonment history were associated with HCV infection in all age groups. Strong relationships between an individual's 'HCV score' and their risk of testing HCV antibody positive were observed. An estimated 78% (95% CI 75% to 81%), 82% (95% CI 80% to 84%), 80% (95% CI 78% to 82%) and 80% (95% CI 77% to 82%) of HCV infections across the age groups (<25, 25-29, 30-39 and ≥40 years) would be avoided if participants in the upper four quintiles of HCV scores fell instead into the lowest quintile. Conclusions Knowledge of HCV status has important implications for public health and care and treatment. Risk assessment strategies may assist in alerting PWID who are at increased risk of HCV infection to present for testing.

Opioid drug abuse and modulation of immune function: consequences in the susceptibility to opportunistic infections

Infection rate among intravenous drug users (IDU) is higher than the general public, and is the major cause of morbidity and hospitalization in the IDU population. Epidemiologic studies provide data on increased prevalence of opportunistic bacterial infections such as TB and pneumonia, and viral infections such as HIV-1 and hepatitis in the IDU population. An important component in the intravenous drug abuse population and in patients receiving medically indicated chronic opioid treatment is opioid withdrawal. Data on bacterial virulence in the context of opioid withdrawal suggest that mice undergoing withdrawal had shortened survival and increased bacterial load in response to Salmonella infection. As the body of evidence in support of opioid dependency and its immunosuppressive effects is growing, it is imperative to understand the mechanisms by which opioids exert these effects and identify the populations at risk that would benefit the most from the interventions to counteract opioid immunosuppressive effects. Thus, it is important to refine the existing animal model to closely match human conditions and to cross-validate these findings through carefully controlled human studies. Better understanding of the mechanisms will facilitate the search for new therapeutic modalities to counteract adverse effects including increased infection rates. This review will summarize the effects of morphine on innate and adaptive immunity, identify the role of the mu opioid receptor in these functions and the signal transduction activated in the process. The role of opioid withdrawal in immunosuppression and the clinical relevance of these findings will also be discussed.

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.

Development of a nurse-led primary healthcare service for injecting drug users in inner-city Sydney

Injecting drug users (IDUs) experience numerous health problems, but report barriers to utilising general practitioners (GPs). A nurse-led Harm Minimisation-based Primary Healthcare (HMPH) service for IDUs was established within a needle and syringe program in inner-city Sydney with Area Health Service medical support and clinical governance. This paper aimed to describe the HMPH service, review service utilisation and assess nurses’ perceptions of their work with IDUs. A review of the most recent 200 clinic files was undertaken. Service utilisation, GP and other health service use and access were extracted and analysed using SPSS. A semi-structured qualitative interview with clinic nurses regarding their experience working with IDUs and local GPs was conducted and analysed. Since its inception in mid-2006, the service has been utilised by 417 clients. Of the most recent 200 files, blood-borne virus and sexually transmitted infection screening were the primary reason for presentation (64.5%). At least one follow-up visit was attended by 90% of clients. A total of 62% of clients reported consulting a GP in the last 12 months. The service provided 102 referrals. Nurses believed that IDUs tend to utilise GPs ineffectively and that self-care is a low priority, but that they can support IDUs to overcome some barriers to GPs and facilitate access. Targeted primary health care services led by nurses with focussed medical support and co-located with needle and syringe programs can fill an important gap in delivering and facilitating health care to IDUs.

The self-reported personal wellbeing of a sample of Australian injecting drug users

AIMS

To examine the self-reported personal wellbeing of a sample of Australian injecting drug users (IDU) using a standardized instrument and determine the key correlates of variations in self-reported personal wellbeing.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional survey of 881 Australian IDU.

MEASUREMENTS

Self-reported personal wellbeing collected using the Personal Wellbeing Index (PWI).

FINDINGS

IDU scored significantly lower than the general Australian population on the PWI and all subscales. Lower PWI scores were associated with a range of socio-demographic, drug use and other health and social characteristics. Across all PWI subscales, lower personal wellbeing scores were associated with unemployment, past 6-month mental health problems and more frequent injecting (all P < 0.05).

CONCLUSIONS

The PWI is sufficiently sensitive to distinguish between IDU and the general population, and to identify key correlates of PWI among IDU. Some domains canvassed within the scale, such as health, standard of living and life achievements, are well within the scope of current intervention strategies, such as pharmacotherapy maintenance treatment and housing and employment support services. This suggests that the PWI could be useful in clinical settings by allowing structured identification of the areas of a person's life to be addressed as a part of a treatment regimen. In order to inform targeted prevention and intervention efforts, longitudinal studies of PWI and its correlates among IDU are required.

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.

Clinical trial literacy among injecting drug users in Sydney, Australia: A pilot study

This pilot study examined knowledge, understanding and perceived acceptability of key methodological concepts in clinical trials among injecting drug users (IDUs) in Sydney, Australia. Participants were clinical trial-experienced (n = 17) and trial-naïve (n = 99) IDUs recruited from community needle and syringe programs, and through institutions involved in clinical trials with IDU participants. Cross-sectional data were collected via a study-specific interviewer-administered survey. Following detailed verbal explanations, higher proportions of trial-experienced than trial-naïve participants demonstrated an understanding of all clinical trial concepts assessed, including single blinding (94% versus 60%); placebo (94% versus 49%); equipoise (71% versus 60%); comparison (59% versus 46%); randomisation (59% versus 21%); and double blinding (47% versus 3%). Multivariate analyses indicated a better understanding among trial-experienced participants. Participants who demonstrated an understanding of 'placebo' and 'double blinding' were significantly more likely to perceive these concepts to be acceptable than those who did not. Results indicate the need for targeted education programs that adequately inform IDUs about clinical trial concepts prior to recruitment to a clinical trial, and support adaptations of informed consent procedures to ensure trial participants' comprehensive understanding of methodologies and their implications.

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.