Repeat participation in annual cross-sectional surveys of drug users and its implications for analysis.

OBJECTIVE: We sought to establish the extent of repeat participation in a large annual cross-sectional survey of people who inject drugs and assess its implications for analysis. RESULTS: We used "porn star names" (the name of each participant's first pet followed by the name of the first street in which they lived) to identify repeat participation in three Australian Illicit Drug Reporting System surveys. Over 2013-2015, 2468 porn star names (96.2%) appeared only once, 88 (3.4%) twice, and nine (0.4%) in all 3 years. We measured design effects, based on the between-cluster variability for selected estimates, of 1.01-1.07 for seven key variables. These values indicate that the complex sample is (e.g.) 7% less efficient in estimating prevalence of heroin use (ever) than a simple random sample, and 1% less efficient in estimating number of heroin overdoses (ever). Porn star names are a useful means of tracking research participants longitudinally while maintaining their anonymity. Repeat participation in the Australian Illicit Drug Reporting System is low (less than 5% per annum), meaning point-prevalence and effect estimation without correction for the lack of independence in observations is unlikely to seriously affect population inference.

The effects of needle-sharing and opioid substitution therapy on incidence of hepatitis C virus infection and reinfection in people who inject drugs.

Although high hepatitis C virus (HCV) prevalence has been observed in people who inject drugs (PWID) for decades, research suggests incidence is falling. We examined whether PWIDs' use of opioid substitution therapy (OST) and their needle-and-syringe sharing behaviour explained HCV incidence. We assessed HCV incidence in 235 PWID in Melbourne, Australia, and performed discrete-time survival with needle-sharing and OST status as independent variables. HCV infection, reinfection and combined infection/reinfection incidences were 7·6 [95% confidence interval (CI) 4·8-11·9], 12·4 (95% CI 9·1-17·0) and 9·7 (95% CI 7·4-12·6) per 100 person-years, respectively. Needle-sharing was significantly associated with higher incidence of naive HCV infection [hazard ratio (HR) 4·9, 95% CI 1·3-17·7] but not reinfection (HR 1·85, 95% CI 0·79-4·32); however, a cross-model test suggested this difference was sample specific. Past month use of OST had non-significant protective effects against naive HCV infection and reinfection. Our data confirm previous evidence of greatly reduced HCV incidence in PWID, but not the significant protective effect of OST on HCV incidence detected in recent studies. Our findings reinforce the need for greater access to HCV testing and prevention services to accelerate the decline in incidence, and HCV treatment, management and support to limit reinfection.

A randomised controlled trial using mobile advertising to promote safer sex and sun safety to young people.

Mobile phone text messages (SMS) are a promising method of health promotion, but a simple and low cost way to obtain phone numbers is required to reach a wide population. We conducted a randomised controlled trial with simultaneous brief interventions to (i) evaluate effectiveness of messages related to safer sex and sun safety and (ii) pilot the use of mobile advertising for health promotion. Mobile advertising subscribers aged 16-29 years residing in Victoria, Australia (n = 7606) were randomised to the 'sex' or 'sun' group and received eight messages during the 2008-2009 summer period. Changes in sex- and sun-related knowledge and behaviour were measured by questionnaires completed on mobile phones. At follow-up, the sex group had significantly higher sexual health knowledge and fewer sexual partners than the sun group. The sun group had no change in hat-wearing frequency compared with a significant decline in hat-wearing frequency in the sex group. This is the first study of mobile advertising for health promotion, which can successfully reach most young people. Challenges experienced with project implementation and evaluation should be considered as new technological approaches to health promotion continue to be expanded.

Markers and risk factors for HCV, HBV and HIV in a network of injecting drug users in Melbourne, Australia.

BACKGROUND AND AIMS: Current injecting drug users (IDU) in major street drug markets within greater Melbourne were recruited to a longitudinal study on blood borne viruses. Here we investigated risk factors for hepatitis C virus (HCV), hepatitis B virus (HBV) and HIV infection in these IDU at the time of their recruitment. METHODS: Three hundred and eighty-two IDU completed detailed questionnaires on their drug use and risk behaviours, and provided blood samples for serology testing. These data were analysed using univariate and multivariate techniques. RESULTS: The overall prevalence of exposure to HCV, HBV and HIV was estimated at 70%, 34% and <1%, respectively. Independent predictors of HCV exposure were history of imprisonment (RR 1.34, 95% CI 1.19-1.52), use of someone else's needle or syringe (RR 1.23, 95% CI 1.07-1.42), >7.6years length of time injecting (RR 1.21, 95% CI 1.07-1.37), and originating from Vietnam (RR 1.12, 95% CI 1.07-1.18). Independent predictors of HBV exposure were HCV exposure (RR 2.15, 95% CI 1.35-3.43), >7.6years length of time injecting (RR 1.57, 95% CI 1.17-2.13) and originating from outside Australia (RR 1.60, 95% CI 1.22-2.10). Neither prison- nor community-applied tattoos predicted HCV or HBV exposure. Up to 31% of IDU who injected for 1year or less were HCV antibody positive, as were 53% of those who injected for 2years or less. CONCLUSIONS: Ongoing engagement with young IDU, through the provision of harm reduction education and resources, is critical if we are to address blood borne viral infections and other health and social harms associated with injecting drug use.

Differences in the social networks of ethnic Vietnamese and non-Vietnamese injecting drug users and their implications for blood-borne virus transmission.

The social networks of 49 ethnic Vietnamese injecting drug users (IDUs) and 150 IDUs of other ethnicities recruited in Melbourne, Australia, were examined for ethnic differences in distribution of hepatitis C virus infection risk using social network analysis and molecular epidemiology. Vietnamese IDUs were more highly connected than non-Vietnamese IDUs, and more likely to be members of dense injecting sub-networks. More related infections were detected in IDUs with discordant ethnicities than were captured in the social network data; nonetheless, most dyads and most IDU pairs with related infections had matching ethnicity, confirming that mixing was assortative on that criterion. Mixing was not obviously dissortative by risk; low-risk Vietnamese IDUs injected more frequently than did correspondingly low-risk non-Vietnamese IDUs, but results for other measures were reversed or equivocal. Network measurements suggest that ethnic Vietnamese IDUs are at elevated risk of blood-borne infection, a conclusion supported by their relatively high HIV prevalence.

Tattooing in prisons--not such a pretty picture.

BACKGROUND: Tattooing in prison represents a unique combination of risk factors for blood borne virus (BBV) transmission because it is illicitly performed by untrained operators with homemade, unsterile, and frequently-shared equipment. It occurs in a setting where a high proportion of people are already infected with hepatitis C virus (HCV) and other BBVs. OBJECTIVES: This study measured the frequency of tattoo acquisition by prisoners inside and outside prison, and the associations between tattooing, injecting drug use, and HCV infection risk. METHODS: A cross-sectional survey was conducted in correctional facilities in Victoria, Australia. Participants completed a questionnaire that asked about injecting drug use and tattooing and provided a finger-prick blood sample that was tested for HCV antibody. RESULTS: Six hundred and forty-two prisoners participated in the study; 449 had ever been tattooed, of whom 182 (41%) had been tattooed in adult or juvenile prison. Of the participants who were not tattooed professionally, 27% reported someone using the same needle, and 42% reported someone had used the ink before them. Prisoners with a history of drug injection were more likely to have a tattoo and to have acquired a tattoo in prison (OR 3.0; CI 1.7-5.4). The HCV antibody-positive prisoners were more likely to have acquired a tattoo in prison compared with HCV antibody-negative prisoners. CONCLUSIONS: Acquiring a tattoo in prison was common and the reports of sharing the tattooing needle and ink was high, placing prisoners at risk of acquiring HCV through tattooing in prison. Trials need to be undertaken that evaluate the risk and benefits of legal tattoos in prison.

Detection of multiple hepatitis C virus genotypes in a cohort of injecting drug users.

Multiple genotypes of the hepatitis C virus (HCV) were detected in five of 138 HCV RNA positive injecting drug users (IDUs) recruited in Melbourne, Australia. Two were detected by combined LiPA and core and NS5a region sequencing, and three more (selected for testing due to their high-risk behaviour) by heteroduplex mobility analysis. We conclude that the true prevalence of mixed infection in IDUs is undoubtedly higher than the 3.6% (five of 138) we observed, and is underestimated by LiPA, the most common method of genotyping. As responsiveness to HCV treatment varies significantly with genotype, a high prevalence of mixed HCV infections in IDUs must diminish overall treatment efficacy and lessen our ability to reduce the burden of HCV-related disease.

HIV in prison: what are the risks and what can be done?

Prisons are recognised worldwide as important sites for transmission of blood-borne viruses (BBVs). There are two reasons why transmission risks in prison are higher than in the community. First, in most western countries, many prison entrants have histories of injecting drug use, and thus already have high prevalences of BBVs. Second, the lack or under-supply of preventive measures (such as clean needle and syringes or condoms) in most prisons, combined with extreme social conditions, creates extra opportunities for BBV transmission. HIV prevalence in prisoners in more developed countries ranges from 0.2% in Australia to over 10% in some European nations. There are case reports of HIV being transmitted by sharing injecting equipment and sexual activity. Tattooing has been reported as a risk factor for the transmission of BBVs in prison. Access to condoms and needle and syringe programmes in prisons is extremely limited, despite success when they have been introduced. The vast majority of prison inmates are incarcerated for only a few months before returning to the community--thus they are, over the long term, more appropriately regarded as 'citizens' than 'prisoners'. Public health policy must involve all sections of the community, including prison inmates, if we are to reduce transmission of HIV and other BBVs.

Incidence of bloodborne virus infection and risk behaviours in a cohort of injecting drug users in Victoria, 1990-1995.

OBJECTIVE: To assess changes in risk behaviours for transmission of bloodborne viruses and incidences and prevalences of these viruses in a field-recruited cohort of injecting drug users. DESIGN: Prospective longitudinal cohort study. SETTING: Metropolitan and rural Victoria, June 1990 to December 1995. SUBJECTS: 626 current injecting drug users (i.e., who had injected drugs within the previous 12 months). MAIN OUTCOME MEASURES: Seroconversion to HIV and hepatitis B and C viruses (HBV and HCV), risk behaviours for infection. RESULTS: HIV incidence was very low (0.2 per 100 person-years). HCV incidence was high (10.7 per 100 person-years), but fell throughout the study, although the downward trend did not reach statistical significance. HBV incidence was moderate (1.8 per 100 person-years) and did not fall. Prevalence of risk behaviours, notably sharing needles and syringes, decreased significantly. CONCLUSIONS: Significant change has occurred in the risk behaviours of the cohort, confirming results of cross-sectional studies of injecting drug use. This change may be responsible for the apparent decline in HIV and HCV incidence. Further studies are needed to monitor the incidence of bloodborne viruses in injecting drug users. Efforts to decrease risk of transmission should continue.