HIV infection in young men in northern Thailand, 1991-1998: increasing role of injection drug use

Comparing Injecting Risk Behaviors of Long-Term Injectors with New Injectors in Tehran, Iran

BACKGROUND

Global estimates suggest there are 15.6 million people who inject drugs (PWID) of whom 17.8% are living with HIV.Few studies have characterized newly-onset injectors with long-term injectors and its association with injecting risk behaviors.

OBJECTIVES

We examined the relationship between length of injection and risk behaviors among people who inject drugs (PWID) in Tehran, Iran.

METHODS

A cross-sectional study was conducted among PWID, from March to August 2016 in Tehran, Iran. PWID were recruited by convenience and snowball sampling from five Drop-in Centers (DIC) located in the south of Tehran. Our primary independent variable was length of injecting career, defined as the number of months since injecting initiation. Those defined as new injectors (were injecting for less than 18 months), and long-term injectors (as injecting drugs for more than 18 months). We reported the adjusted odds ratio (aOR) point estimate and 95% confidence interval (CI95%) as the effect measure. The level of significance used in multiple logistic regression model was 0.05. We used STATA v. 11 for all analyzes.

RESULTS

The analytical sample comprised of 500 participants (100% male). Mean (±SD) age of PWID with a length of injection history was 31.2 ± 7.2 years. Overall, 270 (54%) (CI95%: 49.6%, 58.4%) of participants were long-term injectors. The average age of drug use initiation among long-term injectors group was lower as compared to new injectors group (31.2 vs. 29.4, p < 0.001). The odds of distributive syringe sharing among new injectors were two times higher than long-term injectors (AOR = 2.1, 95% CI 1.4-4.7). The odds of receptive syringe sharing were lower among new injectors group (AOR = 0.7, CI95% 0.2-0.87), compared to long-term injectors. New injectors had higher odds of reusing their own syringes (OR = 2.8, 95% CI: 1.4-5.7; p = 0.01).

CONCLUSIONS

Improvements in harm reduction service provision can occur through taregted risk reduction education for new injectors focusing on reducing distributive syringe sharing among them.

Cognitive performance profiles by latent classes of drug use

BACKGROUND AND OBJECTIVES

The relationship between substance use and cognitive deficits is complex and requires innovative methods to enhance understanding. The present study is the first to use LCA to examine associations of drug use patterns with cognitive performance.

METHODS

Cocaine/heroin users (N = 552) completed questionnaires, and cognitive measures. LCA identified classes based on past-month drug use and adjusted for probabilities of group membership when examining cognitive performance. Latent indicators were: alcohol (ALC), cigarettes (CIG), marijuana (MJ), crack smoking (CS), nasal heroin (NH), injection cocaine (IC), injection heroin (IH), and injection speedball (IS). Age and education were included as covariates in model creation.

RESULTS

Bootstrap likelihood ratio test (BLRT) supported a 5-class model. Prevalent indicators (estimated probability of over 50%) for each class are as follows: "Older Nasal Heroin/Crack Smokers" (ONH/CS, n = 166.9): ALC, CIG, NH, CS; "Older, Less Educated Polysubstance" (OLEP, n = 54.8): ALC, CIG, CS, IH, IC, and IS; "Younger Multi-Injectors" (MI, n = 128.7): ALC, CIG, MJ, IH, IC, and IS; "Less Educated Heroin Injectors" (LEHI, n = 87.4): CIG, IH; and "More Educated Nasal Heroin" users (MENH, n = ALC, CIG, NH. In general, all classes performed worse than established norms and older, less educated classes performed worse, with the exception that MENH demonstrated worse cognitive flexibility than YMI.

DISCUSSION AND CONCLUSIONS

This study demonstrated novel applications of a methodology for examining complicated relationships between polysubstance use and cognitive performance.

SCIENTIFIC SIGNIFICANCE

Education and/or nasal heroin use are associated with reduced cognitive flexibility in this sample of inner city drug users.

Do Thai parents really know about the sexual risk taking of their children? A qualitative study in Bangkok

This qualitative study explores the perceptions of parents and adolescents toward sexual risk-taking behaviors. In-depth interviews were conducted with 30 parents and 30 adolescents (aged 13-14 years) in Bangkok, and were analyzed by using coding and thematic analysis. The results showed that although parents generally believed that Thai teens begin to have sex at an early age and engage in sexual risk-taking behaviors, they trusted that their teens would follow parental guidance and rules and not engage in sexual activity at this age. Most of the Thai teens reported that their parents were not really aware of their sexual behaviors because of their tendency to keep their sexual stories secret for fear of being scolded, blamed, and punished. The teens also reported that they wanted their parents to listen, give them warmth and more freedom, and be more in touch with their activities. Parents expressed their need for knowledge and skills so that they could help guide their adolescent children to avoid sexual risk-taking behaviors. A family intervention specifically aimed at empowering Thai urban parents is needed.

The impact of Thai family matters on parent-adolescent sexual risk communication attitudes and behaviors

This article reports on a combined family-based substance abuse and HIV-prevention intervention targeting families with 13-14-year-old children in Bangkok, Thailand. Families (n = 340) were randomly and proportionally selected from 7 districts in Bangkok with half randomly assigned to an experimental or control condition. Families in the intervention condition were exposed to 5 interactive booklets about adolescent substance use and risky sexual behavior. Trained health educators followed up by phone to encourage completion of each booklet. Primary outcomes reported in this article include whether the intervention increased the frequency of parent-child communication in general or about sexual risk taking in particular as well as whether the intervention reduced discomfort discussing sexual issues. The authors also tested to see whether booklet completion was associated with communication outcomes at the 6-month follow-up. Multivariate findings indicate that the intervention had a significant impact on the frequency of general parent-child communication on the basis of child reports. The intervention had a marginal impact on the frequency of parent-child communication about sexual issues on the basis of parent reports. Booklet completion was associated with reduced discomfort discussing sex and was marginally associated with frequency of parent-child discussion of sex on the basis of parent reports only. These findings indicate that a family-based program can influence communication patterns.

A multilevel analysis of the impact of socio-structural and environmental influences on condom use among female sex workers

This study uses multilevel analysis to examine individual, organizational and community levels of influence on condom use among female commercial sex workers (FSW) in the Philippines. A randomized controlled study involving 1,382 female commercial sex workers assigned to three intervention groups consisting of peer education, managerial training, combined peer and managerial intervention and a usual care control group was conducted. The results of the multilevel analysis show that FSWs who work in establishments with condom use rules tend to have a higher level of condom use (β = .70, P < 0.01). Among the different intervention groups, the combined peer and managerial intervention had the largest effect on condom use (β = 1.30, P < 0.01) compared with the usual care group. Using a three-level hierarchical model, we found that 62% of the variation lies within individuals, whereas 24% and 14% of the variation lies between establishments, and communities, respectively. Standard errors were underestimated when clustering of the FSWs in the different establishments and communities were not taken into consideration. The results demonstrate the importance of using multilevel analysis for community-based HIV/AIDS intervention programs to examine individual, establishment and community effects.

Correlates of forced sex among populations of men who have sex with men in Thailand

Although forced sex is a correlate of HIV infection, its prevalence and associated risks are not well described among men who have sex with men (MSM) in developing-country settings. Between March and October 2005, we assessed the prevalence of forced sex and correlates among populations of MSM (this includes general MSM, male sex workers, and male-to-female transgender persons) in Thailand using a community-based sample. Participants were enrolled from venues around Bangkok, Chiangmai, and Phuket using venue day-time sampling. Handheld computer-assisted self-interviewing was used to collect demographic and behavioral data and logistic regression evaluated factors associated with forced sex, defined as ever being forced to have sexual intercourse against one's will. Of the 2,049 participants (M age, 24.8 years), a history of forced sex was reported by 376 (18.4%) men and, of these, most were forced by someone they knew (83.8%), forced more than once (67.3%), and had first occurrence during adolescence (55.1%). In multivariate analysis, having a history of forced sex was significantly associated with being recruited in Phuket, classification as general MSM or transgender (versus classification as male sex worker), drug use, increased number of male sexual partners, and buying sex. The findings in our assessment were consistent with assessments from Western countries. Longitudinal studies are needed to understand the mechanisms of the relationships between forced sex correlates found in our assessment and HIV acquisition and transmission risks.

Injection prevalence and risks among male ethnic minority drug users in northern Thailand

Thailand's rate of HIV due to drug use is increasing, and nearly one-half of clients at a drug treatment centre in the north are from marginalized ethnic minority groups. We describe and compare socio-demographics, drug use, and sexual practices across ethnic minority people presenting for treatment at the Northern Drug Treatment Center, Mae Rim, Thailand. A prevalence study was conducted between February 1999 and January 2000. Trained interviewers administered a baseline questionnaire to 1,865 people admitted to the Northern Drug Dependence Treatment Center. Ethnic minority (Karen, Akha, Hmong, Lisu, and Lahu) males were included in this analysis (n = 629). Between 7% and 28% of each minority group had ever injected drugs (p = 0.002). Ninety-five per cent of men ever injecting had used heroin. Younger age, speaking Thai language, having a job with higher contact with Thais, and prior drug detoxification were significantly associated with injection in multivariate analysis, while Hmong and Lisu ethnicity were protective. Using occupation and language as proxies, contact with Thais and concomitant acculturation may be a risk for injection among this population. The inadvertent consequences of acculturation as it relates to injection and HIV risk must be addressed.

Inconsistent condom use among young men who have sex with men, male sex workers, and transgenders in Thailand

Young men who have sex with men (MSM) are at risk for HIV infection. We investigated inconsistent condom use among 827 sexually active young MSM (15-24 years), enrolled using venue-day-time sampling in Bangkok, Chiang Mai and Phuket, Thailand. Data was collected using palmtop computer-assisted self-interviewing. Of participants, 33.1% were regular MSM, 37.7% were male sex workers (MSWs) and 29.1% were transgenders (TGs). Of MSM, 46.7%, of MSWs, 34.9% and of TGs, 52.3% reported recent inconsistent condom use. In multivariate analysis, receptive anal intercourse (MSM, MSWs), receptive and insertive anal intercourse, living alone and a history of sexual coercion (MSWs), not carrying a condom when interviewed (MSM, TGs), lower education, worrying about HIV infection and a history of sexually transmitted infections (TGs) were significantly and independently associated with inconsistent condom use. Interventions for young MSM are needed and must consider the distinct risk factors of MSM, MSWs, and TGs.

Gender and access to HIV testing and antiretroviral treatments in Thailand: why do women have more and earlier access?

In the recent scale-up of antiretroviral treatment, gender differences in access to treatment have been reported. In Thailand, as the HIV epidemic became more generalised, there has been a shift from men being disproportionately affected to increased vulnerability of women. In 2007, the Living with Antiretrovirals (LIWA-ANRS 12141) study investigated the gender distribution of all adult patients receiving antiretroviral therapy (N=513 patients) in four community hospitals in northern Thailand and factors influencing the disparities observed. From this retrospective life-event history survey, we found that proportionately more women (53%) were receiving antiretroviral therapy than men, an unexpected result for a country with a higher proportion of infections among men. They were more likely to initiate treatment within one year of diagnosis and were at a more advanced stage of the disease compared to women. This gender distribution is partly explained by the evolving dynamics of the HIV epidemic, initial prioritization of mothers for treatment and earlier access to HIV testing for women. These issues are also entangled with gender differences in the reasons and timing to HIV testing at the individual level. This study found that the majority of men underwent HIV testing for health reasons while the majority of women were tested following family events such as a spouse/child death or during pregnancy. Further qualitative research on gender specific barriers to HIV testing and care, such as perceived low risk of infection, poor access to medical care, lack of social support, actual or anticipated HIV/AIDS-related stigma would provide greater insight. In the meantime, urgent efforts are needed to increase access to voluntary counselling and testing inside and outside the family setting with targeted interventions for men.

Sexual behavior and risk factors for HIV infection among homosexual and bisexual men in Thailand

HIV prevalence and associated risk behaviors were examined among Thai bisexually active men (MSMW, n = 450) and men who have sex with men only (MSM-only, n = 1,125). Cross sectional venue-day-time sampling was used to collect data. Chi-square and logistic regression were used to identify HIV risk factors. HIV prevalence was 8.2% among MSMW and 21.2% among MSM-only. Consistent condom use with male partners was higher among MSMW (77.6%) than MSM-only (62.9%), and lower with female partners (44.4%). Lack of family confidant, migration, concern about acquiring HIV infection, and self-reported STD were associated with HIV prevalence among MSMW. Older age, lower educational level, residing in Bangkok or Chiang Mai, living away from family, recruitment from a sauna, increased frequency of visiting the surveyed venue, practicing receptive or both receptive and insertive anal intercourse, inconsistent condom use with male paying partners, and a history of drug use were associated with HIV prevalence in MSM-only.

Stigma, social reciprocity and exclusion of HIV/AIDS patients with illicit drug histories: a study of Thai nurses' attitudes

Background

Stigma is a key barrier for the delivery of care to patients living with HIV/AIDS (PLWHA). In the Asia region, the HIV/AIDS epidemic has disproportionately affected socially marginalised groups, in particular, injecting drug users. The effect of the stigmatising attitudes towards injecting drug users on perceptions of PLWHA within the health care contexts has not been thoroughly explored, and typically neglected in terms of stigma intervention.

Methods

Semi-structured interviews were conducted with a group of twenty Thai trainee and qualified nurses. Drawing upon the idea of 'social reciprocity', this paper examines the constructions of injecting drug users and PLWHA by a group of Thai nurses. Narratives were explored with a focus on how participants' views concerning the high-risk behaviour of injecting drug use might influence their attitudes towards PLWHA.

Results

The analysis shows that active efforts were made by participants to separate their views of patients living with HIV/AIDS from injecting drug users. While the former were depicted as patients worthy of social support and inclusion, the latter were excluded on the basis that they were perceived as irresponsible 'social cheaters' who pose severe social and economic harm to the community. Absent in the narratives were references to wider socio-political and epidemiological factors related to drug use and needle sharing that expose injecting drug users to risk; these behaviours were constructed as individual choices, allowing HIV positive drug users to be blamed for their seropositive status. These attitudes could potentially have indirect negative implications on the nurses' opinions of patients living with HIV/AIDS more generally.

Conclusion

Decreasing the stigma associated with illicit drugs might play crucial role in improving attitudes towards patients living with HIV/AIDS. Providing health workers with a broader understanding of risk behaviours and redirecting government injecting drug policy to harm reduction are discussed as some of the ways for stigma intervention to move forward.

A systematic review of published evidence on intervention impact on condom use in sub-Saharan Africa and Asia

OBJECTIVE

There has been much debate about the value of condoms in HIV/STI programming. This should be informed by evidence about intervention impact on condom use, but there is limited compiled literature. This review aims to quantify intervention impact on condom use in sub-Saharan Africa and Asia, in different types of partnership.

METHODS

A systematic review was conducted of papers published between 1998 and 2006 presenting evaluations of interventions involving condom promotion in sub-Saharan Africa and Asia. Data on reported postintervention levels of condom use, and various measures of changes in condom use, by partnership type, were compiled.

RESULTS

A total of 1374 abstracts were identified. Sixty-two met the inclusion criteria (42 reporting significant increases in condom use): 44 from sub-Saharan Africa and 18 from Asia. Many (19) reported on condom use in commercial sex (15 significant), six on use with casual partners (three significant), 11 on use in marital/steady partnerships (nine significant), 14 on use by youths (eight significant) and 20 combined partnership types (11 significant). There is substantial evidence of interventions targeted at sex workers and clients achieving large increases in condom use. Far less evidence exists of intervention impact on condom use in casual relationships. In primary partnerships, postintervention condom use was low unless one partner was knowingly HIV-infected or at high-risk, or avoiding pregnancy. Evaluations of interventions targeting youths recorded limited increases in condom use.

CONCLUSIONS

The findings illustrate the range of evidence about postintervention condom use in different partnerships, and how patterns of use are influenced by partnership type and perceptions of risk. Where possible, intervention studies should also assess biological endpoints, since prevention of infection is the measure of most interest in the evaluation of condom promotion interventions.

Novel heroin injection practices: implications for transmission of HIV and other bloodborne pathogens

BACKGROUND

This paper describes injection risk in an out-of-treatment population of young heroin users in Hanoi, Vietnam, including use of a soft-tissue portal known as a "cay ma" (injection sac).

METHODS

Data from a large cross-sectional survey (N=1270) are used to describe the prevalence of this practice and its association with disease. Additionally, data from an ethnographic substudy on injectors serve to elaborate injectors' rationales for this injection practice.

RESULTS

This practice was common in this sample, appearing soon after initiation of habitual injection. Injectors report that this allows rapid and reliable access to a vein; strategic advantages in a dense urban environment where rapid injection, typically in public settings, is necessary to avoid discovery or arrest. Additionally, this practice is believed to mitigate risk for vein damage from co-morbid promethazine hydrochloride injection.

CONCLUSIONS

This practice may draw lymphocytes to injection sites, thereby increasing risk for transmission of bloodborne pathogens. Structural and behavioral interventions are needed for young heroin users in Vietnam.

Inconsistent condom use with steady and casual partners and associated factors among sexually-active men who have sex with men in Bangkok, Thailand

HIV/STD risk behavior has not been examined in community samples of men who have sex with men (MSM) in Thailand. The sexually-active sample (n=927) was recruited from bars, saunas, and parks; 20% identified as bisexual and 17% tested HIV-positive. Inconsistent (<100%) condom use was reported by 45% of those with steady partners and 21% of those with casual partners in the prior three months. 21% had heard of effective HIV treatments (n=194), among whom 44% believed HIV was less serious and 36% said their risk behavior had increased after hearing about the treatments. In multivariate analysis, HIV-positive status, gay-identification, getting most HIV information from the radio, believing HIV can be transmitted by mosquito bite, and concern about acquiring an STD were associated with inconsistent condom use during anal sex; slightly older age (25-29 vs. 18-24 years) was associated with more consistent condom use. HIV/STD risk-reduction strategies for MSM in Bangkok should clearly state sexual risk to individuals in this population.

Clients of sex workers in different regions of the world: hard to count

OBJECTIVES

To estimate the proportion of the male population that reports having paid for sex in different regions.

METHODS

Clients of sex workers were identified from representative samples of men asked in face-to-face interviews whether they had had sex in exchange for money or whether they had paid for sex, in the last 12 months. A total of 78 national household surveys and nine city based surveys were selected for inclusion. Where such surveys were not available, results of behavioural surveillance surveys and of research studies were also used. Using national estimates, a median percentage of men who reported paying for sex was calculated for each region.

RESULTS

The median percentage of men who exchanged sex for money in the last 12 months in all regions was around 9-10%, with estimates from 13% to 15% in Central African region, 10 to 11% in Eastern and southern Africa, and 5-7% in Asia and Latin America. Estimates for men who paid sex were much lower at around 2-3% with ranges from 7% in the South African region to 1% in Asia and West Africa.

CONCLUSIONS

Although errors of measurement and critical issues of definitions and interpretation exist, this compilation represents a first attempt to obtain reasonably coherent estimates of the proportion of men who were clients of sex workers at regional level. Large discrepancies between regions were found. Further improvements in national estimates will be critical to monitor coverage of HIV prevention programmes for sex workers and clients, and to improve estimates of national HIV infection prevalence levels in low and concentrated HIV epidemics.

HIV voluntary counseling and testing and HIV incidence in male injecting drug users in northern Thailand: evidence of an urgent need for HIV prevention

HIV voluntary counseling and testing (VCT), an important strategy for HIV prevention and care, has been available in all government hospitals in Thailand since 1992. We assessed factors associated with HIV testing, its uptake, and estimates of HIV incidence after HIV testing among male northern Thai injecting drug users (IDUs) admitted for inpatient drug treatment. Participants were interviewed about risk behaviors and HIV testing history before VCT was provided as part of the study. Of 825 IDUs who participated, 36% reported a prior HIV test. Factors associated with prior HIV testing in multiple logistic regression analysis included higher education and having >1 lifetime sex partner. Needle sharing was not associated with prior HIV testing. Of the 298 men with a prior test, 80% reported a negative result on their last prior HIV test, of whom 28% tested positive in our study, leading to an estimated incidence rate of 10.2 per 100 person-years. Fifty-nine percent of the IDUs who reported a prior HIV test stated that they did not receive pre- and/or posttest counseling. HIV incidence among IDUs remains high despite having VCT. Extending HIV prevention and harm reduction programs is urgently needed for IDUs in the region.

Behavioral and social issues among volunteers in a preventive HIV vaccine trial in Thailand

Behavioral and social issues were investigated in 363 phase I/II preventive HIV-1 vaccine trial volunteers in Thailand. These issues included risk behavior, HIV knowledge, distress, and social consequences of vaccine trial participation. Data were collected at baseline and at 4-, 8-, and 12-month follow-up visits. Volunteers reported relatively low levels of risk behaviors at baseline and at follow-up. Overtly negative reactions from family or friends were reported by 5.9%. No experiences of discrimination in employment, health care, or insurance were reported. Mean levels of distress were low throughout the trial, and HIV-related knowledge was high, although it was common to consider the possibility of HIV transmission through casual contact. Findings add to the evidence that preventive HIV vaccine trials are feasible in Thailand.

Evidence of a previously undocumented epidemic of HIV infection among men who have sex with men in Bangkok, Thailand

BACKGROUND

The HIV prevalence and associated risk behaviours in Thai men who have sex with men (MSM) are unknown. This information is crucial to inform and implement targeted preventive interventions for this population.

METHODS

A cross-sectional assessment, using venue-day-time sampling, was conducted. Participants were 1121 Thai men who were 18 years or older, were residents of Bangkok, and reported anal or oral sex with a man during the past 6 months. Oral fluid specimens were tested for HIV antibody. Demographic and behavioural data were collected using an interviewer-administered Palm based automated questionnaire.

RESULTS

HIV prevalence was 17.3% (194 of 1121). Mean age was 26.9 years (median 25 years), and university education was completed by 42.5%. Sex with men and women during the past 6 months was reported by 22.3%; sex with a woman ever, 36%; and unprotected sexual intercourse during the past 3 months, 36.0%. Alcohol use during the past 3 months was common (73.7%); drug use was rare (2.5%). Multivariate logistic regression analyses showed lower education, recruitment from a park, self-identification as homosexual, receptive and insertive anal intercourse, more years since first anal intercourse, and more male sex partners to be significantly and independently associated with HIV prevalence.

CONCLUSIONS

HIV infection is common among MSM in Bangkok. HIV prevention programs are urgently needed to prevent further spread of HIV in this young and sexually active population.

Changes in HIV prevalence among young Thai men as defined by hepatitis C co-infection as a marker for mode of transmission

To obtain a better understanding of the evolving HIV-1 epidemic in Thailand, we utilized antibody to hepatitis C virus (HCV) to indicate the mode of HIV-1 transmission. Although the proportion of men with HCV co-infection increased between 1995 and 2000, the prevalence was similar, whereas the prevalence of men not co- infected decreased (1.93-0.46%). This suggests that HIV-1 infection associated with parenteral transmission has been stable despite a dramatic reduction in the sexual transmission of HIV-1.

Thailand's response to the HIV epidemic: yesterday, today, and tomorrow

Thailand's comprehensive national response to the HIV/AIDS epidemic has been extensively documented since the beginning of epidemic. Substantial progress in the fight against HIV/AIDS has been made because awareness of the problem was raised. Top-level political commitment and multisectoral strategies mobilized funds and human resources to implement the control program at all levels. Behavioral change resulting in increased condom use in brothels on a national scale rose from virtually nil to more than 95%. This was accompanied by a 90% reduction of the sexually transmitted disease rate. In parallel, the rate of new HIV infections dropped by 80%. Despite these achievements, there remains an urgent need to continue efforts to ensure universal and unfailing condom use. Further, Thailand needs to establish pragmatic innovative approaches to reduce transmission, especially among injection drug users, women, and youth, as well as to develop effective strategies for implementation of antiretroviral treatment. Further strategies also need to consider the changing cultural, social, and economic characteristics of the Thai populations.

HIV prevention among drug users: an international perspective from Thailand

All too often in reviews of HIV prevention needs, the role of drugs is summarily dismissed, especially in contexts where the heterosexual epidemic is the primary mode of transmission. Substance use and abuse, particularly injection drug use, play a paramount role in maintaining the heterosexual spread of HIV, as well as in maintaining epidemics where heterosexual spread of the infection has come under control due to prolonged and concerted HIV prevention activities. This article presents several themes to place in the developing country context what we have learned about substance use-related HIV prevention and the special problems of HIV interventions. First, the article briefly examines the international production and trade routes of opium and heroin and their role in the HIV epidemic, as well as the importance of substance abuse in heterosexual epidemics. Second, it presents a case study of HIV control that has been internationally acclaimed as one of the few successes in achieving a meaningful reduction in heterosexually transmitted HIV--Thailand. The Thai response to the injection drug use HIV epidemic, however, has been muted, and its impact on future epidemic dynamics is evaluated. The article concludes with a discussion of existing research gaps concerning the role of drug use in HIV epidemics in the developing world, with Thailand as an example.

Drug-related HIV in South and South-East Asia

While there has been significant advancement in the knowledge on effective HIV prevention methods among injecting drug users (IDUs), and their demonstrated success, in particular the impact of availability and use of clean injecting equipment on reducing HIV prevalence among IDUs, in Australia, the US and the UK, progress made in implementation of actual interventions focused on IDUs in South and South-East Asia is less than satisfactory. This paper examines some of the critical issues related to the context and causes of inadequate drug-related HIV prevention programmes in Asia. It also raises questions relating to evidence-based interventions to be scaled up in the region, including the need for sufficient resources anda conducive policy and legalenvironment.

The association between hepatitis C virus and HIV-1 in preparatory cohorts for HIV vaccine trials in Thailand

OBJECTIVES

To study the association between hepatitis C virus (HCV) and HIV-1, and HCV seropositivity as an indicator of HIV-1 risk behavior for HIV vaccine preparatory cohorts in Thailand.

DESIGN

Cross-sectional study of HIV-1-infected persons identified at screening for potential HIV vaccine trial cohort studies.

METHODS

Sera from HIV-1-infected and uninfected volunteers was matched by age, sex, and community, and tested for HCV reactivity. Logistic regression methods were used to measure associations between HIV-1, HCV and other risk factors for HIV infection.

RESULTS

The prevalence of HCV among HIV-negative controls was 8.3% (6/72) for men and 4.2% (5/118) for women. Co-infection with HIV and occurred in 50.7% (37/73) of men and 3.4% (4/118) of women. Among men who reported injection drug use (IDU), 96.4% (27/28) were HCV seropositive. No women reported IDU. HCV was associated with HIV infection [odds ratio (OR), 11.3; 95% confidence interval (CI), 4.4-29.3] and IDU (OR, 12.0; 95% CI, 3.4-41.9) among men, but not women (OR, 0.8; 95% CI, 0.2-3.0). After adjustment for potential confounding, HCV, but not IDU, remained strongly associated with HIV-1 infection among men (OR, 9.4; 95% CI, 2.7-32.6).

CONCLUSIONS

The strong associations between HCV seropositivity, HIV-1 infection, and IDU history suggest that IDU was reported accurately in this study. The surprisingly high prevalence of HCV among HIV-1-infected young men may assist health policy makers in the choice of behavioral interventions for this important subgroup of the population.

An assessment of preferential attachment as a mechanism for human sexual network formation

Recent research into the properties of human sexual-contact networks has suggested that the degree distribution of the contact graph exhibits power-law scaling. One notable property of this power-law scaling is that the epidemic threshold for the population disappears when the scaling exponent rho is in the range 2 < rho < or = 3. This property is of fundamental significance for the control of sexually transmitted diseases (STDs) such as HIV/AIDS since it implies that an STD can persist regardless of its transmissibility. A stochastic process, known as preferential attachment, that yields one form of power-law scaling has been suggested to underlie the scaling of sexual degree distributions. The limiting distribution of this preferential attachment process is the Yule distribution, which we fit using maximum likelihood to local network data from samples of three populations: (i) the Rakai district, Uganda; (ii) Sweden; and (iii) the USA. For all local networks but one, our interval estimates of the scaling parameters are in the range where epidemic thresholds exist. The estimate of the exponent for male networks in the USA is close to 3, but the preferential attachment model is a very poor fit to these data. We conclude that the epidemic thresholds implied by this model exist in both single-sex and two-sex epidemic model formulations. A strong conclusion that we derive from these results is that public health interventions aimed at reducing the transmissibility of STD pathogens, such as implementing condom use or high-activity anti-retroviral therapy, have the potential to bring a population below the epidemic transition, even in populations exhibiting large degrees of behavioural heterogeneity.

HIV prevalence and risks among injection and noninjection drug users in northern Thailand: need for comprehensive HIV prevention programs

The authors sought to determine sociodemographic and sexual and drug use risk factors for HIV infection among drug users in northern Thailand adjacent to the Golden Triangle. The authors enrolled patients admitted for inpatient drug detoxification at one treatment center in northern Thailand and studied HIV risks and prevalence using an interviewer-administered questionnaire and serum collection with HIV pretest and posttest counseling. Between February 1, 1999 and January 31, 2000, 1865 patients admitted for opiate and methamphetamine dependence completed study procedures. Overall HIV prevalence was 10.3%: 30.0% among 513 injection drug users (IDUs) and 2.8% among non-IDUs (OR = 14.8, 95% CI: 10.2, 21.6). HIV seroprevalence was 2.4% among exclusive methamphetamine users (98% of whom are non-IDUs) and 3.4% among opium smokers. Injection drug use was the dominant risk factor in multivariate models. Although Thailand is widely recognized as having a successful national response to the heterosexual HIV epidemic, seroprevalence in IDUs remains high. Despite a sharp increase of non-IDUs admitted to the drug treatment center, HIV infection and risks remained high among IDUs in northern Thailand. HIV prevention campaigns need to focus on IDUs and to implement harm reduction strategies to reduce transmission to IDUs and further contain the HIV epidemic in Thailand.

AIDS and public policy: the lessons and challenges of "success" in Thailand

Thailand's public policy on AIDS is widely cited as one of the few examples of an effective national AIDS prevention program anywhere in the world. The Thai experience shows that a national response that mobilized key government and NGO partners and targeted the highest-risk transmission can be effective in reducing the scope of the epidemic, even when action is delayed. Based on interviews with policymakers, AIDS program managers, technical specialists, donors, and NGOs and on a review of the data, we highlight the lessons from public policy on AIDS in Thailand for other developing countries, review the state of the Thai epidemic and public policy in 2000, and identify three strategic priorities for the next phase of the response.

Environmental-structural factors significantly associated with consistent condom use among female sex workers in the Dominican Republic

OBJECTIVE

To examine the influence of environmental-structural factors in promoting consistent condom use (CCU) among female sex workers (FSW) and their regular paying partners in the Dominican Republic.

METHODS

A cross-sectional survey was conducted with 288 FSW recruited from 41 sex establishments in Santo Domingo from March to June 1998. Sex workers were asked about their sexual behavior, self-efficacy at negotiating safe sex, perceived intimacy with their most recent regular paying partner, and the physical, social and policy environment of the establishment where they worked. Factor and reliability analysis were utilized to develop aggregate measures for self-efficacy (Cronbach's Alpha 0.60), intimacy (Cronbach's Alpha 0.80), and environmental-structural support (Cronbach's Alpha 0.72).

RESULTS

Controlling for sociodemographic characteristics of participants in multivariate analyses, environmental-structural support for condom use and HIV/sexually transmitted infection (STI) prevention was a significant predictor of CCU (OR 2.16; CI 1.18-3.97) among FSW and their regular paying partners. Safe sex self-efficacy (OR 2.80; CI 1.31-5.97) and low perceived intimacy with the most recent regular paying partner (OR 7.20; CI 3.49-14.83) were also significantly associated with CCU in multivariate analysis.

CONCLUSION

Environmental-structural support for condom use and HIV/STI prevention is a significant predictor of CCU among FSW in the context of regular paying partnerships. Environmental-structural factors, in addition to relational and individual cognitive factors, should be assessed and addressed by behaviorally guided theory, research and interventions related to HIV/STI prevention and female sex work.

Validating the effects of social desirability on self-reported condom use behavior among commercial sex workers

Most studies on the transmission of HIV depend upon self-reports of risky behaviors. This study examines if there is social desirability bias with respect to self-reported condom use behavior, assesses the reliability of a self-reported condom use scale, and validates the self-reported findings with clinical sexually transmitted infection (STI) diagnosis for commercial sex workers (N = 1,383) in the Philippines. The reliability of the condom use scale is .81, and results from confirmatory factor analysis indicate that the data fit the model well. Sex workers who reported using condoms consistently had significantly lower rates of sexually transmitted infections compared to those who never used a condom (t = 7.79, p < .01). It was concluded that no social desirability bias existed with the self-reported condom use scale. Furthermore, the condom use measure was found to have a high level of concurrent validity with STI outcomes.