Exposure of intravenous drug users to AIDS retrovirus, Sydney, 1985

Australia's response to HIV among people who inject drugs

Australia's prompt and effective response to HIV among people who inject drugs is recognized internationally. In the early 1980s, there was growing awareness of the evolving threat presented by HIV. Despite erroneous but commonly held assumptions that people who inject drugs generally disregard their health, injecting drug users contributed significantly to Australia's response to HIV. They formed peer-based organizations which advocated for: engaging affected communities in policy development and implementation; funding for peer education; and access to sterile injecting equipment. While government fear of appearing to condone injecting illicit drugs delayed the bi-partisan political support needed to implement programs to provide readily accessible sterile injecting equipment, needles and syringe programs were established relatively quickly. Strong evidence supports the effectiveness, safety, and cost-effectiveness of Australia's early, decisive, and pragmatic public health and human rights-based approach. Without a comprehensive package of harm reduction and peer-based responses, HIV epidemics can develop rapidly among and from people who inject drugs.

Estimating the cost-effectiveness of needle-syringe programs in Australia

OBJECTIVE

To evaluate the impact and cost-effectiveness of needle-syringe programs (NSPs) with respect to HIV and hepatitis C virus (HCV) infections among Australian injecting drug users (IDUs).

DESIGN/METHODS

A health economic analysis was conducted incorporating a mathematical model of HIV and HCV transmission among IDUs. An empirical relationship between syringe availability and receptive syringe sharing (RSS) was assessed. We compared the epidemiological outcomes and costs of NSP coverage (status quo RSS of 15-17%) with scenarios that had no NSPs (RSS of 25-50%). Outcomes included numbers of HIV and HCV infections averted, lifetime health sector costs, and cost per quality-adjusted life year (QALY) gained. Discounting was applied at 3% (sensitivity: 0%, 5%) per annum.

RESULTS

We estimated that NSPs reduced incidence of HIV by 34-70% (192-873 cases) and HCV by 15-43% (19 000-77 000 cases) during 2000-2010, leading to 20 000-66 000 QALYs gained. Economic analysis showed that NSP coverage saved A$70-220 million in healthcare costs during 2000-2010 and will save an additional A$340-950 million in future healthcare costs. With NSPs costing A$245 million, the programs are very cost-effective at A$416-8750 per QALY gained. Financial investment in NSPs over 2000-2010 is estimated to be entirely recovered in healthcare cost savings by 2032 with a total future return on investment of $1.3-5.5 for every $1 invested.

CONCLUSION

Australia's early introduction and high coverage of NSPs has significantly reduced the prevalence of HIV and HCV among IDUs. NSPs are a cost-effective public health strategy and will result in substantial net cost savings in the future.

HIV prevalence among IDUs in Australia: a methodological review

A review was carried out of Australian studies which have measured the prevalence of HIV infection among injecting drug users (IDUs). The review considered published studies which had reported on serologically-determined HIV prevalence. There were five studies reported from specialized sexually-transmissible disease of HIV clinics, five studies reported from health services aimed at IDUs, three studies reported from other health services and one multi-centre behavioural study. The main findings from the studies were that HIV prevalence in IDUs has been low in Australia, apart from in male IDUs who also had homosexual contact. HIV prevalence ranged from 20 to 24% in male IDUs reporting homosexual contact and from 0 to 5% in other IDUs.The studies, while reflecting a range of research methodologies, are subject to a number of limitations. Most of the studies did not provide detailed analyses of HIV prevalence by age and sex or behavioural factors, and several studies used sampling frames which were not clearly defined. There is little available information on temporal trends in seroprevalence and geographical comparisons are rendered difficult by differences in the study methodology. Adoption of standardized, continuing seroprevalence surveys on IDUs would provide a better means of monitoring the occurrence of HIV infection in this group, which has been a key determinant of the course of the HIV epidemic in a number of Western countries.

Blood-borne viruses and their survival in the environment: is public concern about community needlestick exposures justified?

BACKGROUND

More than 30 million needle syringes are distributed per year in Australia as a component of harm-reduction strategies for injecting drug users (IDU). Discarded needle syringes create considerable anxiety within the community, but the extent of needlestick injuries and level of blood-borne virus transmission risk is unclear. We have undertaken a review of studies of blood-borne virus survival as the basis for advice and management of community needlestick injuries.

METHODS

A Medline review of published articles on blood-borne virus survival and outcome from community injuries.

RESULTS

Hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) can all survive outside the human body for several weeks, with virus survival influenced by virus titer, volume of blood, ambient temperature, exposure to sunlight and humidity. HBV has the highest virus titers in untreated individuals and is viable for the most prolonged periods in needle syringes stored at room temperature. However, prevalence of HBV and HIV are only 1-2% within the Australian IDU population. In contrast, prevalence of HCV is 50-60% among Australian IDUs and virus survival in needle syringes has been documented for prolonged periods. There have been no published cases of blood-borne virus transmission following community needlestick injury in Australia.

CONCLUSION

The risk of blood-borne virus transmission from syringes discarded in community settings appears to be very low. Despite this, procedures to systematically follow up individuals following significant needlestick exposures sustained in the community setting should be developed.

Epidemiological methods for research with drug misusers: review of methods for studying prevalence and morbidity

Epidemiological studies of drug misusers have until recently relied on two main forms of sampling: probability and convenience. The former has been used when the aim was simply to estimate the prevalence of the condition and the latter when in depth studies of the characteristics, profiles and behaviour of drug users were required, but each method has its limitations. Probability samples become impracticable when the prevalence of the condition is very low, less than 0.5% for example, or when the condition being studied is a clandestine activity such as illicit drug use. When stratified random samples are used, it may be difficult to obtain a truly representative sample, depending on the quality of the information used to develop the stratification strategy. The main limitation of studies using convenience samples is that the results cannot be generalised to the whole population of drug users due to selection bias and a lack of information concerning the sampling frame. New methods have been developed which aim to overcome some of these difficulties, for example, social network analysis, snowball sampling, capture-recapture techniques, privileged access interviewer method and contact tracing. All these methods have been applied to the study of drug misuse. The various methods are described and examples of their use given, drawn from both the Brazilian and international drug misuse literature.

Falling incidence of HIV infection in a cohort of clinic attenders

It is widely accepted that changes in sexual behaviour in the mid-1980s drastically reduced the spread of human immunodeficiency virus (HIV) through male homosexual contact in Western countries, but documentation of changes in infection rates has been based on observation of subjects enrolled in cohort studies, who may be highly selected and motivated. In this study, the incidence of HIV seroconversion was investigated among people attending a major site of HIV testing, counselling and patient care in Sydney. Over the period March 1985 to June 1990, 2,301 people were tested for HIV antibody on more than one occasion, following a negative result at the first test. On the basis of subsequent tests, 107 were found to have seroconverted during the study period, including 91 men who reported homosexual or bisexual contact as their only exposure to HIV. Overall, the incidence rate of HIV infection among men reporting homosexual or bisexual contact was 404 per 100 person-years of follow-up. Under various methods of calculation, the incidence was estimated to have declined between 1985 and 1989-1990. However, there was continuing HIV seroconversion in 1989-1990 and no indication of declining incidence in younger men. The fall in HIV incidence documented in this study supports the role of HIV prevention programs aimed at homosexual and bisexual men.

Factors associated with heroin users' AIDS risk-taking behaviours

A survey was undertaken in Sydney in 1989 to identify factors associated with behaviour involving risk for human immunodeficiency virus infection. Self-report data on needle-sharing and sexual practices were collected from 91 heroin users entering a residential, drug-free detoxification unit. Data were analysed using polytomous and ordinal logistic regressions. Heroin-dependent subjects who also had a current alcohol problem were significantly more likely than others to report high risk needle-sharing behaviour. Subjects with more than one sexual partner in the last three months were significantly more likely to use condoms while those with a current benzodiazepine problem were significantly less likely to use condoms. Qualitative data suggest that high risk needle-sharing behaviour most often occurred around the time of relapse to injecting drug use and among homeless drug users occupying derelict buildings in inner-city suburbs.

Dogma disputed: potential endemic heterosexual transmission of human immunodeficiency virus in Australia

The concept of tertiary sexual transmission of human immunodeficiency virus (HIV) has been central to government efforts to communicate notions of risk to heterosexuals in Australia. Data on heterosexually transmitted acquired immune deficiency syndrome (AIDS) and HIV for Australia are reviewed with emphasis given to the probability of misclassification bias in the heterosexually acquired and 'other/undetermined' categories. Tertiary cases are almost certainly rare in Australia, with little evidence of any increase in their incidence since the first cases were recorded. Three factors (low probability of exposure, the infectivity of HIV and a comparatively low rate of sexual partner change) make it improbable that Australian heterosexuals with no risk factors will experience endemic HIV infection, with a caveat to this conclusion lying in the potential of Australian sex tourism to Southeast Asia for introducing HIV into the Australian heterosexual population. Four hegemonic factors which have acted to suppress any serious debate of the notion that HIV in Australia is unlikely to become endemic among heterosexuals are discussed: the political 'democratization' of risk inspired by concerns that gay men should not be further vilified as a victim group; the preventive imperative; a reluctance among health educators to question the very foundations of the message they are employed to deliver; and a reluctance to curtail 'Trojan horse' benefits to sexually transmissible disease prevention engendered by HIV education promoting safe sex messages.

Entry of human immunodeficiency virus infection into a population of injecting drug users, Victoria, 1990

OBJECTIVE

To investigate the pathway by which the human immunodeficiency virus (HIV) is entering populations of injecting drug users (IDUs) in Victoria.

DESIGN

A retrospective case-control study comparing the prevalence of self reported risk behaviour in HIV-infected and uninfected Victorian IDUs.

SETTING

Subjects were recruited by trained peer outreach workers from their personal networks, community agencies and Fairfield Hospital outpatients, and by a research worker from the major metropolitan prison.

PARTICIPANTS

People who had been resident in Victoria for the past 12 months and had injected an illicit drug more than once in the previous three years were eligible to participate. Sixty-two such people (28 HIV-infected, 34 not infected) were included in the study.

MAIN OUTCOME MEASURES

The two main hypothesised portals of entry were from the non-IDU homosexual population in Victoria, and from HIV-infected IDUs elsewhere.

RESULTS

male homosexual contact was the most consistent risk factor identified by this study (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.7-23.8). Having lived in or visited Sydney before 1986 was also associated with being infected with HIV (OR, 13.2; 95% CI, 1.5-603), and this was associated with homosexuality. Infected IDUs reported more sharing of injecting equipment than controls (OR, 9.0; 95% CI, 1.5-92.5), particularly with sexual partners; when this was the case, they were more likely to always use the injecting equipment after their partner (61% of cases, 0% of controls; OR, greater than or equal to 4.1; P = 0.0006).

CONCLUSION

Men who have a history of both homosexual contact and injecting drug use represent the group of IDUs at highest risk of HIV infection in Victoria. Although heterosexual and homosexual IDUs may have limited contact only, a larger epidemic of HIV infection in heterosexual IDUs could spread from homosexual IDUs through the sharing of injecting equipment.

The effect of a needle and syringe exchange on a methadone maintenance unit

In November 1986, a pilot needle and syringe exchange was established in Sydney adjacent to a methadone maintenance unit. A retrospective study was carried out to determine the effect of increasing the availability of sterile needles and syringes on the treatment outcome of the methadone maintenance unit. In this study, an increase in availability of sterile needles and syringes was not found to be associated with an increase in the presence of illicit injectable drugs in the urine specimens of clients of the methadone programme compared to a control methadone unit where there was no known change in needle and syringe availability. This study suggests that an increase in the availability of sterile needles and syringes does not appear to lead to an increase in the frequency of intravenous drug use. The possibility of drug and alcohol treatment centres acting as needle and syringe exchange or distribution outlets therefore requires consideration.

Prevalence of maternal HIV infection based on anonymous testing of neonates, Sydney 1989

The presence of antibody to human immunodeficiency virus (HIV) in post-partum women may be inferred by screening the blood of their newborn babies, since maternal IgG antibodies freely cross the placenta. We tested a sample of 10,217 newborns from 10 hospitals covering three areas in Sydney and other metropolitan centres in New South Wales from April to July, 1989. None of the specimens gave a positive test for antibody to HIV. Thus, the prevalence of HIV positive serology in this sample of newborns was found to be zero. It was estimated that the seroprevalence of antibody to HIV among all neonates in the study area was between zero and 0.045% (99% confidence interval). Because newborns are an accessible group for the study of HIV, and can act as surrogates for their mothers, anonymous testing of this sentinel group will remove some of the limitations generalizing the information in the present database of HIV infection in Australia. This study provides baseline data and suggests that there is not a widespread epidemic of HIV infection among heterosexual persons in Australia at the present time and that routine antenatal testing of women for antibody to HIV may not be cost-effective. However, it will be important to repeat this study at regular intervals to detect any increase in HIV seroprevalence.

HIV-related risk-taking behaviour, knowledge and serostatus of intravenous drug users in Sydney

This study was carried out in 1987 to investigate the relationships between human immunodeficiency virus (HIV)-related risk-taking behaviour, demographic characteristics and serostatus of 181 intravenous drug users in Sydney. Subjects were predominantly heterosexual men in their late twenties with limited secondary education. The majority (77%) had been injecting drugs for more than two years and were daily (91%) injectors of heroin (87%). Eighty per cent had shared injection equipment. Condom use was uncommon (15%) except during prostitution (72%). Sixty-nine per cent of all subjects were at risk of HIV infection due to either unsafe sexual practices or sharing of injection equipment. Thirty per cent of the sample had been in prison at some time since 1981 and half of these (15%) had used intravenous drugs and shared injection equipment while in custody. Thirteen per cent of men who had been imprisoned reported anal intercourse with other male prisoners. HIV antibody test results were available from 132 subjects of whom 12 (9%) (95% confidence intervals [CI], 4%-14%) were seropositive. The majority (67%) of seropositive subjects were homosexual/bisexual men but no other behavioural or demographic factor differentiated seropositive from seronegative subjects. The HIV seroprevalence (9%) found in this study of intravenous drug users in Sydney is significantly higher than a 1985 estimate of 0.5% (P less than 0.001). This finding and the level of risk-taking behaviour by this sample indicates that strategies introduced at the time may have been inadequate to prevent HIV infection among intravenous drug users in Sydney. Widespread HIV infection in Australian intravenous drug users may be imminent unless major changes in HIV-related risk-taking behaviour occur in the near future.

Intravenous drug users who present to the Albion Street (AIDS) Centre for diagnosis and management of human immunodeficiency virus infection

Intravenous drug users who presented to the Albion Street (AIDS) Centre for human immunodeficiency virus (HIV) antibody screening during the period March 1, 1985 to January 31, 1989, were included in this study. Information on medical history and HIV risk-related behaviour was collected by means of a standardized, computer-coded medical record. Of the 1222 intravenous drug users in this study, 72.3% were men, 26.9% were women and 0.8% were transsexual, with 60.1% of the total claiming exclusive heterosexuality. Of the sample, 40.2% were current intravenous drug users, and 86.8% recorded having shared needles and syringes. Among this sample, the over-all prevalence of HIV seropositivity was 14.5%. Of subjects who were diagnosed as HIV seropositive, 43.8% were homosexual men, 13.1% were bisexual men and 5.3% were heterosexual men. Of all intravenous drug users, 49.9% had a history of at least one sexually-transmitted disease, with 21.8% reporting a history of more than one. Fifty-two per cent of the sample reported that they had been infected with hepatitis B previously. There was no over-all increase in the annual rate of HIV infection among this population of intravenous drug users. The sexual activity and prevalence of hepatitis and other sexually-transmitted diseases among this group are suggestive of widespread, continuing risk behaviour.

HIV infection in sexually transmissible disease practice in Sydney: the effects of legislation, public education and changing clinical spectrum

The experience with human immunodeficiency virus (HIV) infection of a private inner-city sexually transmissible diseases (STD) clinic in Sydney was quantified. Between February 1984 and March 1988, 2073 of the Clinic's patients were tested for antibodies to HIV on 5095 occasions. Of those tested, 538 (26%) were positive for antibodies to HIV: 532 (98.9%) of the seropositives had practised male homosexual intercourse. This is the highest reported seroprevalence of HIV for any primary care service in Australia. Those individuals seropositive because of other risk behaviours were detected by voluntary contact tracing rather than by screening. Female prostitution was not found to be a risk factor for HIV. In general, rates of first HIV antibody tests were adversely affected by threatening legislation, and temporarily stimulated (among lower-risk persons) by a national television campaign. These data suggest that much of the counselling, detection and management of HIV infection in Australia is occurring in private practice, and that STD services (private and public) are at the forefront of the HIV epidemic. This has implications for disease surveillance and control, health services planning and medical education.

Survival of patients with the acquired immunodeficiency syndrome in Australia

The duration of survival of all persons with the acquired immunodeficiency syndrome (AIDS) in Australia who were diagnosed to July 31, 1987 was analysed by means of standard Kaplan-Meier methods in order to construct survival curves, and by log-rank tests which were used to assess the significance of differences among the curves. The median duration of survival was 10.4 months. Significant (P less than 0.001) differences in the survival curves were found between men and women (median survival, 11.4 and 3.8 months, respectively) by the log-rank test. Patients who were aged 20-49 years at diagnosis had a longer (P less than 0.001) median survival (11.4 months) than did those who were older than 60 years of age (2.7 months) and those who were aged less than 20 years (0.5 months) at diagnosis. Those patients who were infected by way of blood transfusions had a shorter (P less than 0.001) median survival (1.6 months) than did those who were infected through homosexual activity (11.4 months). Median survival time, which was stratified by the disease stage at presentation, varied from 12.4 months in those patients with Kaposi's sarcoma alone to 7.0 months in those patients with lymphoma (P = 0.01). The median survival time for those patients who presented solely with Kaposi's sarcoma was shorter than was that which has been reported from other developed countries. Multivariate analysis of all male cases by means of the proportional-hazards model indicated that the presentation of cases at an age that was greater than 50 years (relative risk, 2.36; 95% confidence interval [CI], 1.63-3.42) was associated independently with a reduced survival time, while the presentation of cases solely with Kaposi's sarcoma (relative risk, 0.67; 95% Cl, 0.49-0.92) was associated independently with an increased survival time. When all cases were included in this analysis, these same predictors of survival were significant; in addition, cases of AIDS as a result of the receipt of a blood transfusion were associated independently with a reduced survival time.

Prevention of human immunodeficiency virus infection among intravenous drug users in New South Wales, Australia: the needles and syringes distribution programme through retail pharmacies

Prevalence of Human Immunodeficiency Virus (HIV) infection among 12, 000 intravenous (i.v.) drug users in New South Wales (NSW) was estimated to be very low in 1985. However, a large increase of HIV infection in this population group could result within a short period.

The NSW government amended existing legislation to permit the sale and possession of sterile needles and syringes. A programme to promote the sale of needles and syringes was launched jointly with the Pharmacy Guild of Australia (NSW Branch) in December 1986. Favourable changes in pharmacists' attitudes were noted four months later. The distribution scheme became an important component of the NSW prevention programme.

There are 2, 039 retail pharmacies throughout NSW. The number of sterile needles and syringes sold through these outlets increased from 4, 200 in January 1987 to 51, 000 in November 1987 with a total of 422, 000 dispensed over this period. The percentage of Pharmacy Guild members involved in the programme increased from 0.5% to 22.5%, covering 38% of the state by November 1987.

During 1987, HIV infection among i.v. drug users remained low. This suggests that the needles and syringes distribution programme contributed significantly towards limiting the spread of HIV infection among i.v. drug users.

Human immunodeficiency virus and female prostitutes, Sydney 1985

One hundred and thirty two female prostitutes and 55 non-prostitutes who were tested for antibodies to human immunodeficiency virus (HIV) were surveyed by questionnaire at this centre. The two groups were well matched for age and were very similar in other except for numbers of their sexual partners. Questions were asked about drug taking, sexual practices, general health, and episodes of sexually transmitted diseases (STDs). None of the women in the survey was found to be seropositive, but both groups were found to be seriously at risk of HIV infection through using intravenous (IV) drugs, having unprotected sexual intercourse with men who used IV drugs, having unprotected sexual intercourse with bisexual men, or exposure to several STDs.

Epidemiology of acquired immunodeficiency syndrome in Australia

Since 1982, when the first case of acquired immunodeficiency syndrome (AIDS) was diagnosed in Australia, a total of 373 cases has been reported to the NHMRC Special Unit in AIDS Epidemiology and Clinical Research to December 19, 1986. Analysis of the data shows that 70% of cases were diagnosed in NSW and of all cases 88% were found to be in homosexual or bisexual men, with the majority aged between 30 and 39 years. Opportunistic infections were found in nearly three-quarters of cases. A mathematical model which has been developed predicts that 1000 cases will have been diagnosed by mid-1988 and nearly that many again in 1990 alone. The absence of a treatment or vaccine, the likelihood that current Australian resources will be inadequate to deal with the predicted number of cases, and the urgent need to establish measures that are aimed at controlling the extent of the disease are emphasized.