Factors influencing a self-limiting HIV outbreak among ethnic Vietnamese injecting drug users in Melbourne, Australia

Cost-effectiveness of alternative strategies for provision of HIV preexposure prophylaxis for people who inject drugs

BACKGROUND

Oral HIV preexposure prophylaxis (PrEP) has been recommended as a means of HIV prevention among people who inject drugs (PWIDs) but, at current prices, is unlikely to be cost-effective for all PWID.

OBJECTIVE

To determine the cost-effectiveness of alternative strategies for enrolling PWID in PrEP.

DESIGN

Dynamic network model that captures HIV transmission and progression among PWID in a representative US urban center.

OUTCOME MEASURES

HIV infections averted, discounted costs and quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

INTERVENTION

We assume 25% PrEP coverage and investigate four strategies: first, random PWID are enrolled (Unselected Enrollment); second, individuals are randomly selected and enrolled together with their partners (Enroll Partners); third, individuals with the highest number of sexual and needle-sharing partnerships are enrolled (Most Partners); fourth, individuals with the greatest number of infected partners are enrolled (Most Positive Partners).

RESULTS

PrEP can achieve significant health benefits: compared with the status quo of no PrEP, the strategies gain 1114 QALYs (Unselected Enrollment), 2194 QALYs (Enroll Partners), 2481 QALYs (Most Partners), and 3046 QALYs (Most Positive Partners) over 20 years in a population of approximately 8500 people. The incremental cost-effectiveness ratio of each strategy compared with the status quo (cost per QALY gained) is $272 000 (Unselected Enrollment), $158 000 (Enroll Partners), $124 000 (Most Partners), and $101 000 (Most Positive Partners). All strategies except Unselected Enrollment are cost-effective according to WHO criteria.

CONCLUSION

Selection of high-risk PWID for PrEP can improve the cost-effectiveness of PrEP for PWID.

Opening up the HIV epidemic: a review of HIV seropositive status disclosure among people who inject drugs

HIV status disclosure plays a crucial role in reducing risk behaviors of drug and sexual partners and thereby limiting HIV transmission. As people who inject drugs (PWID) bear a significant HIV burden and disclosure research among PWID is relatively few, we reviewed the literature to highlight what is known about disclosure among HIV-positive PWID. Searches of articles published from 2000 to 2015 yielded 17 studies addressing different aspects of disclosure, and results are presented by major themes. Our results suggest that despite the difficulties, most PWID (64-86%) disclose their HIV-positive status to trusted individuals (family members and intimate sexual partners) and to those who are known to be HIV-positive. Disclosure to non-intimate sexual partners and fellow drug users is relatively lower. Disclosure decision-making is primarily driven by the perceived positive and negative consequences of disclosure. Subsequent risk reduction practices following disclosure are influenced by the feeling of responsibility, as well as partners' willingness to accept risk. Cultural family values, ethnicity, and different localities were several contextual factors that affect patterns of disclosure and risk behaviors of PWID. Areas for future research are recommended.

HIV treatment outcomes among people who inject drugs in Victoria, Australia

BACKGROUND

People who inject drugs (PWID) are a key population affected by HIV. We assessed the effectiveness of HIV treatment among a clinical cohort of people living with HIV (PLHIV) diagnosed and referred for community-based antiretroviral therapy (ART) in Victoria, Australia.

METHODS

HIV notification data from a central statewide registry were matched with HIV clinical data from two large HIV treatment centers in Melbourne. We used survival analysis and Cox proportional hazard models to estimate time to AIDS and death for PWID in HIV treatment, compared with non-injectors, in the period 1996-2008.

RESULTS

Of the 871 individuals, 93 (10.8%) had injecting as an exposure category and 671 (86%) had ever commenced ART. Adjusted analysis showed younger age, high initial CD4 cell count (>500 cells/mm(3)) or ever having a CD4 cell count >500/mm(3), and more recent calendar year of ART commencement were all associated with reduced hazards for AIDS and death, while older age, low initial CD4 cell count (<200/mm(3)), ever having a CD4 count <200/mm(3) (before or during treatment) and high initial viral load (>5 log10) were associated with increased risk of AIDS and death. PWID were no more likely to experience AIDS (HR 0.98 [0.54-1.80]) or death (HR 0.78 [0.18-3.42]) than non-injectors.

CONCLUSION

Survival of HIV-infected PWID on HIV treatment was equivalent to non-injectors. CD4 cell count, initial viral load, calendar year of commencing ART and age are more important determinants of AIDS and mortality than injecting status for in-treatment PLHIV in Victoria, Australia.

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.

Injection drug users' access to a supervised injection facility in Vancouver, Canada: the influence of operating policies and local drug culture

North America's first supervised injection facility (SIF) was established in Vancouver, Canada, in 2003. Although evaluation research has documented reductions in risk behavior among SIF users, there has been limited examination of the influence of operational features on injection drug users' access to these facilities. We conducted an ethnographic study that included observational research within the SIF, 50 in-depth individual interviews with SIF users, and analysis of the regulatory frameworks governing the SIF. The government-granted exemption allowing the facility to operate legally imposes key operating regulations, as well as a cap on capacity, which results in significant wait times to enter the injecting room. Regulations that prohibit practices that are common in the local drug culture also negatively affect SIF utilization. Restructuring policies that shape the operation of the SIF could enhance access to the facility and permit SIF services to better accommodate local drug use practices.

The effectiveness of harm reduction in preventing HIV among injecting drug users

There is now compelling evidence that harm reduction approaches to HIV prevention among injecting drug users are effective, safe and cost-effective. The evidence of effectiveness is strongest for needle and syringe programs and opioid substitution treatment. There is no convincing evidence that needle and syringe programs increase injecting drug use. The low prevalence approximately 1%) of HIV among injecting drug users reflects the early adoption and rapid expansion of harm reduction in Australia. Countries that have provided extensive needle and syringe programs and opioid substitution treatment appear to have averted an epidemic, stabilised or substantially reduced the prevalence of HIV among injecting drug users. However, despite decades of vigorous advocacy and scientific evidence, the global coverage of needle and syringe programs and opioid substitution treatment falls well short of the levels required to achieve international HIV control.

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.