Faculty Bibliography

OBJECTIVES/OBJECTIVE:To determine infection patterns of sexually transmitted infections that facilitate HIV transmission among HIV-discordant couples. METHODS:112 initial respondents were recruited in an impoverished neighbourhood of Brooklyn, New York. Their sexual (and injection) partners were recruited in up to four additional network sampling waves for a final sample of 465 persons aged 18 years or older. After separate informed consent had been obtained, blood and urine were collected and tested for HIV, type-specific antibodies to herpes simplex virus (HSV-2), syphilis, chlamydia and gonorrhoea. RESULTS:Of 30 HIV-discordant partnerships, five were same-sex male partnerships and 25 were opposite-sex partnerships. No subjects tested positive for syphilis or gonorrhoea. Two couples were chlamydia-discordant. For HSV-2, 16 couples were double-positive, eight discordant, four double-negative, and two comprised a HSV-2-negative with a partner with missing herpes data. CONCLUSIONS:HSV-2 was present in 83% of the HIV-discordant couples, chlamydia in 7%, and syphilis and gonorrhoea in none. HSV-2 is probably more important for HIV transmission than bacterial sexually transmitted diseases because it is more widespread. Even given the limited generalisability of this community-based sample, there seems to be an important HIV-prevention role for herpes detection and prevention activities in places where HIV-infected people are likely to be encountered, including sexually transmitted disease clinics, HIV counselling and testing programmes, prisons, needle exchanges, and drug abuse treatment programmes. The effects of HSV-suppressive therapy in highly impacted groups should also be investigated.

OBJECTIVES/OBJECTIVE:To describe: (a) the prevalence and individual and network characteristics of group sex events (GSEs) and GSE attendees; and (b) HIV/sexually transmitted infection (STI) discordance among respondents who said they went to a GSE together. METHODS AND DESIGN/METHODS:In a sociometric network study of risk partners (defined as sexual partners, persons with whom respondents attended a GSE, or drug injection partners) in Brooklyn, NY, we recruited a high-risk sample of 465 adults. Respondents reported on GSE attendance, the characteristics of GSEs, and their own and others' behaviors at GSEs. Sera and urines were collected, and STI prevalence was assayed. RESULTS:Of the 465 participants, 36% had attended a GSE in the last year, 26% had sex during the most recent of these GSEs, and 13% had unprotected sex there. Certain subgroups (hard drug users, men who have sex with men, women who have sex with women, and sex workers) were more likely to attend and more likely to engage in risk behaviors at these events. Among 90 GSE dyads, in which at least 1 partner named the other as someone with whom they attended a GSE in the previous 3 months, STI/HIV discordance was common [herpes simplex virus (HSV-2): 45% of dyads, HIV: 12% of dyads, and chlamydia: 21% of dyads]. Many GSEs had 10 or more participants, and multiple partnerships at GSEs were common. High attendance rates at GSEs among members of large networks may increase community vulnerability to STI/HIV, particularly because network data show that almost all members ofa large sociometric risk network either had sex with a GSE attendee or had sex with someone who had sex with a GSE attended. CONCLUSIONS:Self-reported GSE attendance and participation were common among this high-risk sample. STI/HIV discordance among GSE attendees was high, highlighting the potential transmission risk associated with GSEs. Research on sexual behaviors should incorporate measures of GSE behaviors as standard research protocol. Interventions should be developed to reduce transmission at GSEs.

People in high-risk neighbourhoods try to protect their friends, neighbours, relatives and others from the social and physical risks associated with sex and drug use. This paper develops and validates a community-grounded questionnaire to measure such 'intravention' (health-directed efforts to protect others). An initial ethnography, including life-history interviews and focus groups, explored the forms of intravention activities engaged in by residents of Bushwick (a high-risk New York City neighbourhood). Grassroots categories of intraventions were derived and questions developed to ask about such behaviours. Face validity and adequacy of the questions were assessed by independent experts. Pre-testing was conducted, and reliability and validity were assessed. An instrument including 110 intravention items was administered to 57 community-recruited residents. Analysis focused on 57 items in 11 domain-specific subscale. All subscales had good to very good reliability; Cronbach's alpha ranged from .81 to .95. The subscales evidenced both convergent and discriminant validity. Although further testing of this instrument on additional populations is clearly warranted, this intravention instrument seems valid and reliable. It can be used by researchers in comparative and longitudinal studies of the causes, prevalence and affects of different intravention activities in communities. It can benefit public health practitioners by helping them understand the environments in which they are intervening and by helping them find ways to cooperate with local neighbourhood-level health activists.

The aim of this study was to estimate the seroprevalence rates of human immunodeficiency virus (HIV), hepatitis B virus (HBV, core antibody), hepatitis C virus (HCV), and syphilis infections and analyze associated risk factors among 504 non-injecting cocaine users (NICU) in Buenos Aires, Argentina. Participants were interviewed in face-to-face sessions through a short structured questionnaire. Using venipuncture, 10 mL of blood was collected. Seroprevalence rates were: HIV (6.3%), HBV (9%), HCV (7.5%), and VDRL (4.2%). The risk of being infected with HIV, HBV, and HCV was significantly associated with having had a sex partner who was either a drug injector or who was known to be HIV positive. HIV and HCV infections were associated with former imprisonment, and HCV was associated with having been tattooed. Because of the rising number of NICU and the multiple infections detected, it is essential to implement prevention strategies focused on this population.

Comparing drug-injecting risk between cities that differ in the legality of sterile syringe distribution for injection drug use provides a natural experiment to assess the efficacy of legalizing sterile syringe distribution as a structural intervention to prevent human immunodeficiency virus (HIV) and other parenterally transmitted infections among injection drug users (IDUs). This study compares the parenteral risk for HIV and hepatitis B (HBV) and C (HCV) infection among IDUs in Newark, NJ, USA, where syringe distribution programs were illegal during the period when data were collected, and New York City (NYC) where they were legal. IDUs were nontreatment recruited, 2004-2006, serotested, and interviewed about syringe sources and injecting risk behaviors (prior 30 days). In multivariate logistic regression, adjusted odds ratios (AOR) and 95% confidence intervals (95% CI) for city differences are estimated controlling for potential city confounders. IDUs in Newark (n = 214) vs. NYC (n = 312) were more likely to test seropositive for HIV (26% vs. 5%; AOR = 3.2; 95% CI = 1.6, 6.1), antibody to the HBV core antigen (70% vs. 27%; AOR = 4.4; 95% CI = 2.8, 6.9), and antibody to HCV (82% vs. 53%; AOR = 3.0; 95% CI = 1.8, 4.9), were less likely to obtain syringes from syringe exchange programs or pharmacies (AOR = 0.004; 95% CI = 0.001, 0.01), and were more likely to obtain syringes from street sellers (AOR = 74.0; 95% CI = 29.9, 183.2), to inject with another IDU's used syringe (AOR = 2.3; 95% CI = 1.1, 5.0), to reuse syringes (AOR = 2.99; 95% CI = 1.63, 5.50), and to not always inject once only with a new, sterile syringe that had been sealed in a wrapper (AOR = 5.4; 95% CI = 2.9, 10.3). In localities where sterile syringe distribution is illegal, IDUs are more likely to obtain syringes from unsafe sources and to engage in injecting risk behaviors. Legalizing and rapidly implementing sterile syringe distribution programs are critical for reducing parenterally transmitted HIV, HBV, and HCV among IDUs.

This paper estimates the prevalence of current injection drug users (IDUs) in 96 large U.S. metropolitan statistical areas (MSAs) annually from 1992 to 2002. Multiplier/allocation methods were used to estimate the prevalence of injectors because confidentiality restrictions precluded the use of other commonly used estimation methods, such as capture-recapture. We first estimated the number of IDUs in the U.S. each year from 1992 to 2002 and then apportioned these estimates to MSAs using multiplier methods. Four different types of data indicating drug injection were used to allocate national annual totals to MSAs, creating four distinct series of estimates of the number of injectors in each MSA. Each series was smoothed over time; and the mean value of the four component estimates was taken as the best estimate of IDUs for that MSA and year (with the range of component estimates indicating the degree of uncertainty in the estimates). Annual cross-sectional correlations of the MSA-level IDU estimates with measures of unemployment, hepatitis C mortality prevalence, and poisoning mortality prevalence were used to validate our estimates. MSA-level IDU estimates correlated moderately well with validators, demonstrating adequate convergence validity. Overall, the number of IDUs per 10,000 persons aged 15-64 years varied from 30 to 348 across MSAs (mean 126.9, standard deviation 65.3, median 106.6, interquartile range 78-162) in 1992 and from 37 to 336 across MSAs (mean 110.6, standard deviation 57.7, median 96.1, interquartile range 67-134) in 2002. A multilevel model showed that overall, across the 96 MSAs, the number of injectors declined each year until 2000, after which the IDU prevalence began to increase. Despite the variation in component estimates and methodological and component data set limitations, these local IDU prevalence estimates may be used to assess: (1) predictors of change in IDU prevalence; (2) differing IDU trends between localities; (3) the adequacy of service delivery to IDUs; and (4) infectious disease dynamics among IDUs across time.

No adequate data exist on patterns of injection drug use (IDU) prevalence over time within racial/ethnic groups in U.S. geographic areas. The absence of such prevalence data limits our understanding of the causes and consequences of IDU and hampers planning efforts for IDU-related interventions. Here, we (1) describe a method of estimating IDU prevalence among non-Hispanic Black and non-Hispanic White adult residents of 95 large U.S. metropolitan statistical areas (MSAs) annually over an 11-year period (1992--2002); (2) validate the resulting prevalence estimates; and (3) document temporal trends in these prevalence estimates. IDU prevalence estimates for Black adults were calculated in several steps: we (1) created estimates of the proportion of injectors who were Black in each MSA and year by analyzing databases documenting injectors' encounters with the healthcare system; (2) multiplied the resulting proportions by previously calculated estimates of the total number of injectors in each MSA and year (Brady et al., 2008); (3) divided the result by the number of Black adults living in each MSA each year; and (4) validated the resulting estimates by correlating them cross-sectionally with theoretically related constructs (Black- and White-specific prevalences of drug-related mortality and of mortality from hepatitis C). We used parallel methods to estimate and validate White IDU prevalence. We analyzed trends in the resulting racial/ethnic-specific IDU prevalence estimates using measures of central tendency and hierarchical linear models (HLM). Black IDU prevalence declined from a median of 279 injectors per 10,000 adults in 1992 to 156 injectors per 10,000 adults in 2002. IDU prevalence for White adults remained relatively flat over time (median values ranged between 86 and 97 injectors per 10,000 adults). HLM analyses described similar trends and suggest that declines in Black IDU prevalence decelerated over time. Both sets of IDU estimates correlated cross-sectionally adequately with validators, suggesting that they have acceptable convergent validity (range for Black IDU prevalence validation: 0.27 < r < 0.61; range for White IDU prevalence: 0.38 < r < 0.80). These data give insight, for the first time, into IDU prevalence trends among Black adults and White adults in large U.S. MSAs. The decline seen here for Black adults may partially explain recent reductions in newly reported cases of IDU-related HIV evident in surveillance data on this population. Declining Black IDU prevalence may have been produced by (1) high AIDS-related mortality rates among Black injectors in the 1990s, rates lowered by the advent of HAART; (2) reduced IDU incidence among Black drug users; and/or (3) MSA-level social processes (e.g., diminishing residential segregation). The stability of IDU prevalence among White adults between 1992 and 2002 may be a function of lower AIDS-related mortality rates in this population; relative stability (and perhaps increases in some MSAs) in initiating IDU among White drug users; and social processes. Future research should investigate the extent to which these racial/ethnic-specific IDU prevalence trends (1) explain, and are explained by, recent trends in IDU-related health outcomes, and (2) are determined by MSA-level social processes.

BACKGROUND:Scientific consensus holds that if, at the outset of the HIV/AIDS epidemic, injection drug users (IDUs) had had better access to sterile syringes, much of the epidemic among IDUs in the U.S. could have been prevented. In the context of preventing infectious diseases, 100% syringe coverage - that is, one sterile syringe per injector for each injection - is a public health goal. Notably, we know little about variations in syringe coverage within the U.S. and elsewhere, or about the social and political factors that might determine this coverage. METHODS:Using data from Holmberg (1996), the 1990 United States Census, the 2000 Beth Israel National Syringe Exchange Survey (n=72), and estimates of IDUs in metropolitan areas (MSAs); (Friedman et al., 2004), we explore the impact of (1) political factors (ACT UP, outreach, early syringe exchange programme (SEP) presence, men who have sex with men (MSM) per capita, drug arrests, and police per capita); (2) local resources for SEPs; and (3) indicators of socioeconomic inequality on SEP coverage. We define "syringe coverage" as the ratio of syringes distributed at SEPs to the number of syringes heroin injectors need in a year. We calculated the number of syringes heroin injectors need in a year by multiplying an estimate of the number of IDUs in each MSA by an estimate of the average number of times heroin injectors inject heroin per year (2.8 times per day times 365 days). In this analysis, the sample was limited to 35 MSAs in which the primary drug of choice among injectors was heroin. RESULTS:SEP coverage varies greatly across MSAs, with an average of 3 syringes distributed per 100 injection events (S.D.=0.045; range: 2 syringes per 10 injection events, to 3 syringes per 10,000 injection events). In bivariate regression analyses, a 1 unit difference in the proportion of the population that was MSM per 1000 was associated with a difference of 0.002 in SEP coverage (p=0.052); early SEP presence was associated with a difference of 0.038 in coverage (p=0.012); and having government funding was associated with a 0.040 difference in SEP coverage (p=0.021). CONCLUSIONS:This analysis suggests that longer duration of SEP presence may increase syringe distribution and enhance successful programme utilization. Furthermore, MSAs with greater proportions of MSM tend to have better SEP coverage, perhaps providing further evidence that grassroots activism plays an important role in programme implementation and successful SEP coverage. This research provides evidence that government funding for SEPs contributes to better syringe coverage.