Risk Factors For HIV Seroconversion Research Articles

A new outbreak of HIV infection among people who inject drugs during the COVID-19 pandemic in Greece.

Multiple HIV outbreaks have been recorded among people who inject drugs (PWID) since 2010. During an intervention for PWID in 2019-2021 in Thessaloniki, Greece, an increasing number of HIV cases was documented. Here, we provide an analysis of this new outbreak. ALEXANDROS was a community-based program and participation included interviewing, rapid HIV/HCV tests, counselling and linkage to care. PWID were recruited through Respondent-Driven Sampling (RDS) in five sampling rounds. Crude and RDS-weighted HIV prevalence estimates were obtained. HIV incidence was estimated from data on 380 initially seronegative PWID with at least two tests. Multivariable Cox proportional hazards model was used to assess risk factors for HIV seroconversion. In total, 1,101 PWID were recruited. At first participation, 53.7% were current PWID, 20.1% homeless, 20.3% on opioid substitution treatment and 4.8% had received syringes in the past 12 months. HIV prevalence (95% CI) was 7.0% (5.6-8.7%) and an increasing trend was observed over 2019-2021 (p=0.002). Two-thirds of the cases (67.5%) were new diagnoses. HIV incidence was 7.0 new infections/100 person-years (95% CI:4.8-10.2). Homelessness in the past 12 months (HR:2.68; 95% CI:1.24-5.81) and receptive syringe sharing (HR:3.86; 95% CI:1.75-8.51) were independently associated with increased risk of seroconversion. By the end of the program, 67.3% of the newly diagnosed cases initiated antiretroviral treatment. A new HIV outbreak among PWID was documented in Greece during the COVID-19 pandemic with homelessness and syringe sharing being associated with increased risk of HIV acquisition. Peer-driven programs targeting the population of high-risk underserved PWID can be used to early identify emerging outbreaks and to improve linkage to HIV care.

Factors Associated With Newly HIV Infection and Transmitted Drug Resistance Among Men Who Have Sex With Men in Harbin, P.R. China

BackgroundThis study aimed to evaluate HIV incidence, factors associated with HIV incidence and transmitted drug resistance (TDR) among newly infected men who have sex with men (MSM) in Harbin, P.R. China.MethodsA cohort study was conducted among MSM in Harbin during 2013 and 2018, with a follow-up frequency of every 6 months. Blood samples from MSM were tested for HIV antibodies, RNA was extracted from plasma, and the pol gene was sequenced, and genotypic drug-resistance analyses were performed.ResultsFrom 2013 to 2018, the overall rate of HIV incidence was 3.55/100 PY. Syphilis infection, unprotected sex with men in the past 6 months, and unawareness of HIV/AIDS knowledge were risk factors for HIV seroconversion. The distribution of HIV genotypes was as follows: CRF01_AE, 57.1%; CRF07_BC, 28.5%; CRF55_01B, 2.0%; B, 8.2%. The prevalence of transmitted drug resistance was 4.08%.ConclusionHIV incidence in MSM in Harbin is moderately high, and transmitted drug resistance exists in the population.

Risk Factors for HIV sero-conversion in a high incidence cohort of men who have sex with men and transgender women in Bangkok, Thailand.

BackgroundWe measured Human Immunodeficiency (HIV) incidence, retention, and assessed risk factors for seroconversion among two previously unreported cohorts of men who have sex with men (MSM) and Transgender Women (TGW) in Bangkok, Thailand between 2017 and 2019.MethodsWe conducted an 18-month prospective cohort study of HIV-uninfected Thai cisgender men and TGW aged between 18 and 35 years who reported sex with men in the past six months and at least one additional risk factor for HIV infection. HIV and syphilis testing and computer-based behavioral questionnaires were administered at each visit. We utilized Poisson regression to calculate HIV incidence rates. A survival random forest model identified the most predictive risk factors for HIV sero-conversion and then used in a survival regression tree model to elucidate hazard ratios for individuals with groups of selected risk factors. Cox proportional hazards (pH) regression evaluated the strength of association between individual covariates and risk of sero-conversion.FindingsFrom April 2017-October 2019, 1,184 participants were screened, 167 were found ineligible, and 1,017 enrolled. Over the 18-month study, visit retention was 93·4% (95% CI 91·6%–94·8%) and HIV incidence was 3·73 per 100 person-years (95% CI 2·79–5·87). Utilizing survival regression tree modeling, those who were 18–20 years of age, reported sexual attraction to mostly or only men, and had five or more lifetime sexual partners were 4·9 times more likely to seroconvert compared to other cohort participants. Factors associated with HIV incidence utilizing Cox pH regression included sexual attraction to mostly or only men (adjusted hazard ratio (aHR) 14·9 (95% CI 20·1–107·9), younger age (18–19 years, aHR 10·88 (95% CI 4·12–28·7), five or greater lifetime sexual partners (aHR 2·0, 95%CI 1·1–3·6), inconsistent condom use with casual partners (aHR 2·43, 95% CI 1·3–4·5), and prior HIV testing (adjusted HR 2·0, 95% CI 1·1–3·5).InterpretationInterpretation HIV incidence remains high among Bangkok-based MSM and TGW. These key populations expressed high interest in participating in efficacy evaluation of future prevention strategies and had high retention in this 18 month study.FundingFunding US National Institute of Allergy and Infectious Diseases (NIAID), Division of AIDS Interagency Agreements (DAIDS) and U.S. Department of the Army.

Risk Factors for HIV Seroconversion in a High Incidence Cohort of Men Who Have Sex with Men and Transgender Women in Bangkok, Thailand

Background: In order to assess feasibility for future HIV prevention trials, we measured HIV incidence, retention, and assessed risk factors for seroconversion among men who have sex with men (MSM) and transgender women (TGW) in Bangkok, Thailand between 2017-2019. Methods: We conducted an 18-month prospective cohort study of HIV-uninfected Thai cisgender men and transgender women who reported sex with men in the past six months. HIV and syphilis testing and computer-based behavioral questionnaires were administered at each visit. We utilized Poisson regression to calculate HIV incidence rates. A survival random forest model identified the most predictive risk factors for HIV seroconversion and then used in a survival regression tree model to elucidate hazard ratios for individuals with groups of selected risk factors. Cox proportional hazards (PH) regression evaluated the strength of association between individual covariates and risk of seroconversion. Findings: From April 2017-October 2019, 1,184 participants were screened, 167 were found ineligible, and 1,017 enrolled. Over the 18-month study, visit retention was 93·4% (95% CI 91·6%-94·8%) and HIV incidence was 3·73 per 100 person-years (95% CI 2·79-5·87). Utilizing survival regression tree modeling, those who were 18-20 years of age, reported sexual attraction to mostly or only men, and had five or more lifetime sexual partners were 4·9 times more likely to seroconvert compared to other cohort participants. Factors associated with HIV incidence utilizing Cox PH regression included sexual attraction to mostly or only men (adjusted hazard ratio (aHR) 14·9 (95% CI 20·1-107·9), younger age (18-19 years, aHR 10·88 (95% CI 4·12-28·7), five or greater lifetime sexual partners (aHR 2·0, 95%CI 1·1-3·6), inconsistent condom use with casual partners (aHR 2·43, 95% CI 1·3-4·5), and prior HIV testing (adjusted HR 2·0, 95% CI 1·1-3·5). Interpretation: HIV incidence remains high among Bangkok-based MSM and TGW. These key populations have high retention and are ideal candidates for efficacy evaluation of future prevention strategies. Funding Statement: This work was supported by the US Army Medical Research and Materiel Command (Military Infectious Diseases Research Program) (cooperative agreements W81XWH-11-2-0174 and W81XWH-07-2-0067 with the Henry M. Jackson Foundation for the Advancement of Military Medicine), the US Army Medical Materiel Development Activity, and the National Institute of Allergy and Infectious Disease (interagency agreement Y1-AI-2642-12 with the US Army Medical Research and Materiel Command) and the Division of AIDS Interagency Agreements (DAIDS IAA Y1-AI-2642-16). Declaration of Interests: T.C. reports grants from U.S. Army, grants from NIH, M.R. and S.V. reports grants from US Army Medical Research and Materiel Command with Henry M. Jackson Foundation for the Advancement of Military Medicine, during the conduct of the study. All other authors report no potential conflicts. Ethics Approval Statement: The study was reviewed and approved by the institutional review boards at Walter Reed Army Institute of Research (WRAIR), Faculty of Tropical Medicine at Mahidol University, and the Royal Thai Army. All participants provided written informed consent prior to enrollment.

1964. Predictive Factors for HIV Seroconversion Among Women Attending an Urban Health Clinic in the South: A Matched Case–control Study in Atlanta, GA

BackgroundIn 2019, Fulton County, GA was named one of 48 priority “hotspots” to target in renewed efforts to end the HIV epidemic in the United States. To more accurately predict women at greatest risk for HIV, we conducted an individually matched case–control study among women who attended a Fulton County health clinic to identify risk factors associated with HIV seroconversion.MethodsWe obtained data about women who sought care at Fulton County Board of Health Sexual Health Clinic (SHC) between 2011 and 2016. Cases were women with at least one clinician-assisted visit (CAV) at the SHC prior to HIV diagnosis date. Controls were women who visited the clinic in this same period but remained HIV negative. Controls were individually matched to cases in a 2:1 matching ratio on race, age at first CAV, and date of first CAV. Conditional logistic regression was used to develop a model for predicting probability of and identifying risk factors for HIV seroconversion.ResultsOf 18,281 women who were HIV negative at their first visit to the SHC between 2011 and 2016, 110 (0.6%) seroconverted before 2018. Of these, 80 (73%) had a CAV prior to HIV diagnosis. Using these 80 cases and 160 matched controls, having a history of gonorrhea, multiple gonorrhea episodes, a history of syphilis, a greater number of sex partners in the past 2 months, anal sex, history of injection drug or crack cocaine use, a history of exchanging drugs/money for sex, and heterosexual sex with more than one sex partner in the last month were associated with HIV seroconversion in bivariate analyses. After conducting backward selection from a fully adjusted model, predictors remaining were: having a history of syphilis (OR = 4.9, 95% CI: 1.4, 16.9), anal sex (OR = 2.9, 95% CI: 1.0, 8.3), and injection drug or crack cocaine use (OR = 34.8, 95% CI: 3.7, 328.1). Women having all three risk factors were six times more likely to seroconvert compared with matched controls without these risk factors.ConclusionOur results offer clinical insights into which women are most at-risk for HIV and are therefore best candidates for initiating HIV prevention interventions like pre-exposure prophylaxis (PrEP) within a HIV “hotspot” in the South.Disclosures All Authors: No reported Disclosures.

Mother-to-child transmission of HIV in the Southern Region of Santa Catarina, from 2005 to 2015: analysis of risk factors to seroconversion in newborns

Abstract Objectives: to analyze both frequency and risk factors for seroconversion among newborns of HIV-positive mothers to HIV. Methods: a cohort study was conducted with children residing in Southern Region of Santa Catarina. Secondary data from the notification files and medical records of newborn's mothers of infected infants were used. The participants were all the newborns from 2005 to 2015 that were exposed to HIV through vertical transmission and attended a municipal health care center. Results: there were 104 cases of infant exposure to HIV. Seroconversion was confirmed in three cases, two of them died of AIDS during the study period. Breastfeeding (PR= 32.7; CI95%= 10.7-99.5; p= 0.002) and non-use of antiretroviral drugs during pregnancy (PR=18.2; CI95%= 2.0-163.0; p= 0.008) were risk factors for HIV seroconversion. Conclusions: seroconversion rates among neonates in Southern Region of Santa Catarina were similar to the national average. Seroconversion was associated with non-use of antiretroviral therapy during pregnancy and breastfeeding.

HIV seroconversion among Baltimore City residents tested at a mobile van programme

BackgroundMany individuals with HIV in the USA are unaware of their diagnosis, and therefore cannot be engaged in treatment services, have worse clinical outcomes and are more likely to transmit...

Daily alcohol use as an independent risk factor for HIV seroconversion among people who inject drugs

AIMS To estimate the relationship between daily alcohol use and HIV seroconversion among people who inject drugs (PWID) in a Canadian setting. DESIGN AND SETTING Data from an open prospective cohort study of PWID in Vancouver, Canada, recruited via snowball sampling and street outreach between May 1996 and November 2013. An interviewer-administered questionnaire including standardized behavioural assessment and HIV antibody testing were conducted semi-annually. Baseline HIV-seronegative participants completing ≥ 1 follow-up visits were eligible for the present analysis. PARTICIPANTS A total of 1683 eligible participants, were followed for a median of 79.8 [interquartile range (IQR) = 33.3-119.1] months. MEASUREMENTS The primary end-point was time to HIV seroconversion, with the date of HIV seroconversion estimated as the mid-point between the last negative and the first positive antibody test results. The primary explanatory variable was self-reported daily alcohol use in the previous 6 months assessed semiannually. Other covariates considered included demographic, behavioural, social/structural and environmental risk factors for HIV infection among PWID (e.g. daily cocaine injection, methadone use, etc.). FINDINGS Of 1683 PWID, there were 176 HIV seroconversions during follow-up with an incidence density of 1.5 [95% confidence interval (CI) = 1.3-1.7] cases per 100 person-years. At baseline, 339 (20.1%) consumed alcohol at least daily in the previous 6 months. In multivariable extended Cox regression analyses, daily alcohol use remained associated independently with HIV seroconversion (adjusted hazard ratio: 1.48; 95% CI = 1.00-2.17). CONCLUSIONS Daily alcohol use appears to be an independent risk factor for HIV seroconversion among our cohort of PWID.

Daily alcohol use as an independent risk factor for HIV seroconversion among people who inject drugs.

To estimate the relationship between daily alcohol use and HIV seroconversion among people who inject drugs (PWID) in a Canadian setting. Data from an open prospective cohort study of PWID in Vancouver, Canada, recruited via snowball sampling and street outreach between May 1996 and November 2013. An interviewer-administered questionnaire including standardized behavioural assessment and HIV antibody testing were conducted semi-annually. Baseline HIV-seronegative participants completing≥1 follow-up visits were eligible for the present analysis. A total of 1683 eligible participants, were followed for a median of 79.8 [interquartile range (IQR)=33.3-119.1] months. The primary end-point was time to HIV seroconversion, with the date of HIV seroconversion estimated as the mid-point between the last negative and the first positive antibody test results. The primary explanatory variable was self-reported daily alcohol use in the previous 6months assessed semiannually. Other covariates considered included demographic, behavioural, social/structural and environmental risk factors for HIV infection among PWID (e.g. daily cocaine injection, methadone use, etc.). Of 1683 PWID, there were 176 HIV seroconversions during follow-up with an incidence density of 1.5 [95% confidence interval (CI)=1.3-1.7] cases per 100 person-years. At baseline, 339 (20.1%) consumed alcohol at least daily in the previous 6 months. In multivariable extended Cox regression analyses, daily alcohol use remained associated independently with HIV seroconversion (adjusted hazard ratio: 1.48; 95% CI=1.00-2.17). Daily alcohol use appears to be an independent risk factor for HIV seroconversion among our cohort of PWID.

Benzodiazepine use as an independent risk factor for HIV infection in a Canadian setting

BackgroundAlthough the harms of prescription drug diversion are of growing international concern, the potential impact of prescription drug use on HIV infection has not been well assessed. We evaluated whether benzodiazepine use was associated with HIV seroconversion among a cohort of persons who inject drugs (PWID) in a Canadian setting. MethodsBetween May, 1996 and November, 2013, data were derived through a prospective cohort study of PWID in Vancouver, Canada. A total of 1682 baseline HIV negative participants were followed for a median of 79.5 months (interquartile range: 32.1–119.1), among whom 501 (29.8%) reported benzodiazepine use at baseline, and 176 seroconverted during follow-up, equal to an incidence density of 1.5 (95% Confidence Interval [CI]: 1.3–1.7) cases per 100 person-years. Poisson regression with time-dependent variables was used to assess whether benzodiazepine use was associated with the time to HIV seroconversion. ResultsAfter adjustment for potential confounders, benzodiazepine use (Adjusted Rate Ratio: 1.50; 95% CI: 1.01–2.24) was independently associated with a higher rate of HIV seroconversion. ConclusionsBenzodiazepine use was an independent risk factor for HIV seroconversion among PWID in this setting. Greater recognition of the safety concerns related to benzodiazepine medications including diversion are needed.

P3.099 Sex Work as an Emerging Risk Factor For HIV Seroconversion Among Injection Drug Users in the SurvUDI Network

BackgroundPrevious analyses of SurvUDI data have shown an emerging positive association between sex work and HIV incidence among injection drug users (IDUs).ObjectiveTo characterise the association between sex work and HIV...

Prospective cohort study of HIV incidence and molecular characteristics of HIV among men who have sex with men(MSM) in Yunnan Province, China

BackgroundYunnan has the largest number of reported HIV/AIDS cases among all Chinese provinces, the reported prevalence of HIV among Yunnan men who have sex with men (MSM) passed 10%, while HIV incidence epidemic and molecular characteristics of new infected Yunnan MSM were not evaluated before.MethodsAn 18 months prospective followed up with a frequency of 3 month per visit were conducted among HIV seronegative MSM in Kunming cityduring 2009–2011. Interviewer-administrated questionnaires were carried out. Blood specimens were obtained to test for syphilis and HIV, in which HIV were evaluated by standard HIV enzyme immunoassay (EIA) and HIV nucleic acid amplification testing (NAAT). Near full-length regions of the HIV-1 were evaluated for subtyping, primary drug resistance mutations.ResultsDuring the follow-up 70.1% of the recruited 378 MSM retained in the cohort. Eleven MSM seroconverted to HIV and fifteen MSM seroconverted to syphilis. The HIV incidence and syphilis incidence was 3.5 (95% CI 1.8-6.2) cases /100 person year(PY) and 5.3 (95% CI 3.0-8.7) cases/100 PY, respectively. Multivariate analysis showed that baseline syphilis infection (aHR, 17.7), occupation (students vs. others [aHR, 5.7], retirees vs. others [aHR, 4.1]), bleeding experience after receptive anal intercourse (aHR,7.6), and minority ethnic(vs. Han) [aHR, 5.7] were independent risk factors for HIV seroconversion(each P<0.05). Among the 7/11 successfully amplified near full-length sequences, 71.4% (5/7) were CRF01_AE, and 28.6% (2/7) were CRF07_BC. Two HIV transmission pairs were detected among seroconverted minority ethnic MSM.ConclusionsHIV incidence was moderately high among Yunnan MSM. Yunnan province need to strengthen both HIV and syphilis screening among MSM population. Some subpopulations of MSM, such as students, retirees and minority ethnic groups require more HIV epidemic surveillance and strengthened behavior interventions. HIV subtypes and primary drug resistance should be continually monitored to track cross-group transmission of HIV strains.

Sexual Partner’s Age as a Risk Factor for HIV Seroconversion in a Cohort of HIV-Negative Homosexual Men in Sydney

Increasing partner age may be an important risk factor for HIV infection in homosexual men. About 20% of 1,427 participants in the Health in Men study in Sydney, Australia, reported that half or more of their partners were much older. Having more partners who were much older was associated with an increased risk of HIV seroconversion (p trend=0.002), and this remained significant after adjustment for participants' age, number of regular and casual partners, and sexual risk behaviour (p trend=0.027). Men who reported much older partners were at increased risk of HIV infection, independent of unprotected anal intercourse with sero-nonconcordant partners.

Assessing and evaluating the combined impact of behavioural and biological risk factors for HIV seroconversion in a cohort of South African women

In this prospective study, we aimed to investigate and evaluate the impact of combinations of behavioural and biological risk factors on HIV acquisition in a cohort of women. Demographic, sexual and biologic risk factors including HIV seroconversion results from 1485 HIV negative women who were enrolled in a HIV prevention trial were used. First, Cox regression models were used to create a prediction model and weighted scoring system. Second, internal validation data-set was used to evaluate the performance characteristics of the model prospectively. In the prediction model, an increasing number of lifetime sexual partners, women who were classified as in a “high risk behavior” group, and those who were not cohabitating with their partners were consistently associated with increased risk of HIV acquisition. Among the baseline biological factors, genital epithelial disruption, genital signs and symptoms, genital discharge and detecting edema, erythma or warts in vulva were all associated with HIV seroconversion. High scores were associated with increased risk of HIV seroconversion. A cut-point score of 15 (out of 44) or higher distinguished an “increased risk” group with a sensitivity of 88%. This study presents reasonable robust analyses for investigating and evaluating epidemiological measures on HIV infection. Results from this study may be included as part of a health promotion to prompt those who are at increased risk of HIV infection which may potentially lead to increased uptake and frequency of testing.

Risk factors for HIV seroconversion in men who have sex with men in Victoria, Australia: results from a sentinel surveillance system

HIV diagnosis rates in men who have sex with men (MSM) began increasing in Australia 10 years ago, and there has been a major resurgence of syphilis. We determined predictors of HIV positivity and seroconversion among MSM in Victoria, Australia. We conducted a retrospective longitudinal analysis of data from MSM who underwent HIV testing between April 2006 and June 2009 at three primary care clinics. Logistic regression was used to determine predictors of HIV positivity and seroconversion. During the study period, 7857 MSM tested for HIV. Overall HIV positivity was 1.86% (95% confidence interval (CI): 1.6-2.2). There were 3272 repeat testers followed for 4837 person-years (PY); 60 seroconverted and HIV incidence was 1.24 (95% CI: 0.96-1.60) per 100 PY. Independent predictors of HIV seroconversion were: an infectious syphilis diagnosis within the last 2 years (adjusted hazard ratio (AHR)=2.5, 95% CI: 1.1-5.7), reporting six or more anal sex partners in the past 6 months (AHR=3.3, 95% CI: 1.8-6.3), reporting an HIV-positive current regular partner (AHR=3.4, 95% CI: 1.1-10.6) and reporting inconsistent condom use with casual partners in the past 6 months (AHR=4.4, 95% CI: 1.7-11.5). Our results call for HIV prevention to target high-risk MSM, including men with a recent syphilis diagnosis or a high numbers of partners, men who have unprotected anal sex with casual partners and men in serodiscordant relationships. The HIV incidence estimate will provide a baseline to enable public health officials to measure the effectiveness of future strategies.

Syphilis and HIV Seroconversion Among a 12-Month Prospective Cohort of Men Who Have Sex With Men in Shenyang, China

Cross-sectional studies have found a high prevalence of syphilis and HIV infection among men who have sex with men (MSM) in China. A total of 218 HIV-negative MSM participated in this prospective cohort study. Interviewer-administered questionnaires were completed, and blood samples were obtained for HIV and syphilis testing, both upon enrollment and at 12-month follow-up. Of enrolled participants, 56% (122) were retained for the full 12-month follow-up period. The cohort had an HIV incidence density of 5.4 (95% CI: 2.0-11.3)/100 person-year (PY) and a syphilis incidence density of 38.5(95% CI: 27.7-50.2)/100 PY. Having syphilis (odds ratio [OR]: 11.4, 95% CI: 1.2-104.7) and more than 5 male sexual partners within the past 12 months (OR: 6.5, 95% CI: 1.1-39.8) were independent risk factors for HIV seroconversion (each P < 0.05). Being married (OR: 3.5, 95% CI: 1.4-8.2) and having more than 5 male sexual partners within the past 12 months (OR: 4.7, 95% CI: 2.0-6.2) were risk factors for syphilis seroconversion, while age > or =30 (OR 2.1, 95% CI 0.7-9.5) and having recently engaged in unprotected receptive anal sex (OR: 2.4, 95% CI: 0.7-13.1) were marginally associated with syphilis seroconversion. The high incidence rates of HIV and syphilis in the Shenyang MSM community are significant cause for concern. The seroconversion rate for syphilis, in particular, indicates the high prevalence of high-risk sexual behaviors and the potential for increased HIV transmission. Appropriate interventions that address MSM-specific issues, including stigma, pressures from traditional society, and bisexual behavior, need to be tailored to inform and empower MSM in order to prevent HIV and syphilis in this community.

Editorial: [Developing Innovative Intervention Approaches for Methamphetamine-Using Men who have Sex with Men Not Currently in Drug Treatment§

Men who have sex with men (MSM) continue to be disproportionately affected by HIV and AIDS. The U.S. Centers for Disease Control and Prevention (CDC) estimates that MSM account for 48% of all men living with HIV and 53% of all new HIV infections in the United States in 2007 [1], and the number of incident cases among MSM continue to increase in the U.S. while incidence has been flat or declining for other risk groups [2]. Further, MSM are at elevated risk for HIV infection throughout the world [3]. Several U.S. studies [4-6] suggest that unprotected anal sex accounts for the acquisition of most HIV infections among MSM, and situational factors play an important role in understanding sexual risk taking. One such factor is the use of methamphetamine during sex. Methamphetamine, a central nervous system stimulant, has been consistently linked to unprotected anal sex among MSM [7] as well as to acquisition of HIV [8]. Methamphetamine use has distinct, long lasting cognitive effects that can lead to sexual disinhibition and impaired judgment, and is often associated with poor adherence to medication regimens [9-11]. Methamphetamine-using MSM are up to 4 times more likely to engage in unprotected anal sex, compared to substance-using MSM who do not use methamphetamine [10]. In a longitudinal study of more than 4000 HIV-negative MSM, Koblin and her colleagues found that prospectively, methamphetamine was an independent risk factor for HIV seroconversion [8]. HIV-positive MSM who use methamphetamine (compared to MSM who do not) are also more susceptible to acquiring other STDs and possibly infecting their sexual partners because methamphetamine also functions as an immunosuppressive drug that decreases CD4 levels while increasing viral load [12]. Although several reviews and summaries have highlighted the efficacy of HIV behavioral interventions for MSM [13-15], CDC has only identified a small number of evidence-based interventions for MSM that reduce sexual risk behavior and none target substance-using men [16]. Behavioral HIV prevention may be particularly challenging for substance-using MSM due to competing physical and emotional needs [17], as well as direct and indirect effects of methamphetamine use. Prior studies have reported on a successful intensive drug treatment model for methamphetamine users to reduce drug use and related harms [18]. In addition, a study of methamphetamine-using MSM found four different treatment-based approaches that successfully reduced sexual risk behavior and methamphetamine use from baseline, but there were no difference between groups in sexual risk reduction [19]. Thus, there remains a need for researchers to develop, implement, and evaluate the efficacy of behavioral HIV prevention interventions for substance-using MSM. In 2006, the CDC Division of HIV/AIDS Prevention announced a scientific initiative to fund formative research and pilot testing of four interventions for methamphetamine-using MSM not currently in drug treatment (CDC PS06-007). This was partly in response to research recommendations from a CDC national consultation on methamphetamine use and risk for HIV and STD transmission [7]. The goal was to demonstrate, through pilot testing, promising interventions for reducing risk for HIV acquisition and transmission. This approach would allow for relatively rapid development, design, and preliminary testing of multiple approaches simultaneously. It was intended that the research program would identify the most promising approaches. Then, these interventions may be further tested with more costly randomized-control trials that would be separately funded by federal or non-federal funders. Four of the following five papers presented here represent interventions that were funded through this funding announcement; the fifth paper represents a seed grant partially funded by CDC. This special issue is devoted specifically to the development and design of interventions for methamphetamine-using MSM who were not currently in drug treatment. As such, the papers focus on innovative formative research, intervention design, and preliminary testing intended to evaluate the feasibility and acceptability of the interventions for the target population, as well as pilot testing of interventions. The papers presented here are not intended to provide behavioral outcome assessments, but to focus on critical developmental work that is often not thoroughly described. We hope to underscore the importance of balancing theoretical and practical issues when designing and testing interventions for such high-risk populations.

Anal Sexually Transmitted Infections and Risk of HIV Infection in Homosexual Men

We examined a range of common bacterial and viral sexually transmitted infections as risk factors for HIV seroconversion in a community-based cohort of HIV-negative homosexual men in Sydney, Australia. Detailed information about HIV risk behaviors was collected by interview twice yearly. Participants were tested annually for HIV, anal and urethral gonorrhea and chlamydia, herpes simplex virus types 1 and 2, and syphilis. In addition, they reported annual diagnoses of these conditions and of genital and anal warts. Among 1427 enrolled participants, 53 HIV seroconverters were identified, giving an incidence of 0.78 per 100 person-years. After controlling for number of episodes of insertive and receptive nonseroconcordant unprotected anal intercourse, there were independent associations with anal gonorrhea (adjusted hazard ratio = 7.12, 95% confidence interval: 2.05 to 24.79) and anal warts (hazard ratio = 3.63, 95% confidence interval: 1.62 to 8.14). Anal gonorrhea and anal warts were independently associated with HIV acquisition. The added HIV prevention value of more frequent screening of the anus to allow early detection and treatment of anal sexually transmitted infections in homosexual men should be considered.

Circumcision and risk of HIV infection in Australian homosexual men

To assess circumcision status as a risk factor for HIV seroconversion in homosexual men. The Health in Men (HIM) study was a prospective cohort of homosexual men in Sydney, Australia. HIV-negative men (n = 1426) were recruited primarily from community-based sources between 2001 and 2004 and followed to mid-2007. Participants underwent annual HIV testing, and detailed information on sexual risk behaviour was collected every 6 months. HIV incidence in circumcised compared with uncircumcised participants, stratified by whether or not men predominantly practised the insertive role in anal intercourse. There were 53 HIV seroconversions during follow-up; an incidence of 0.78 per 100 person-years. On multivariate analysis controlling for behavioural risk factors, being circumcised was associated with a nonsignificant reduction in risk of HIV seroconversion [hazard ratio 0.78, 95% confidence interval (CI) 0.42-1.45, P = 0.424]. Among one-third of study participants who reported a preference for the insertive role in anal intercourse, being circumcised was associated with a significant reduction in HIV incidence after controlling for age and unprotected anal intercourse (UAI) (hazard ratio 0.11, 95% CI 0.03-0.80, P = 0.041). Those who reported a preference for the insertive role overwhelmingly practised insertive rather than receptive UAI. Overall, circumcision did not significantly reduce the risk of HIV infection in the HIM cohort. However, it was associated with a significant reduction in HIV incidence among those participants who reported a preference for the insertive role in anal intercourse. Circumcision may have a role as an HIV prevention intervention in this subset of homosexual men.

Use of Illicit Drugs and Erectile Dysfunction Medications and Subsequent HIV Infection among Gay Men in Sydney, Australia

Use of illicit drugs and oral erectile dysfunction medications (OEM) have been associated with risk behavior among gay men. To determine the effects of illicit drugs and OEM as risk factors for HIV seroconversion in a community-based cohort of HIV-negative homosexually active men in Sydney, Australia. Drug use in the previous 6 months and at the most recent sexual encounter; Most recent occasions of unprotected and protected anal intercourse; HIV-positive diagnosis. From June 2001 to June 2007, participants were followed up with 6-monthly detailed behavioral interviews and annual testing for HIV. Detailed information about sexual, drug-using and other behavior was collected. Among 1,427 participants enrolled, 53 HIV seroconverters were identified by June 2007. At baseline, 62.7% reported using illicit drugs in the previous 6 months, including 10.7% who reported at least weekly use. Illicit drug use was associated with unprotected anal intercourse with casual partners (P < 0.001). Use of illicit drugs was associated with increased risk of HIV infection at a univariate level, and this risk increased with greater frequency of use. This was also true of the use of OEM. Use of each type of illicit drug was included in multivariate analysis, and after controlling for sexual risk behaviors, only use of OEM remained significantly predictive of HIV infection (Hazard ratios [HR] = 1.75, CI = 1.31-2.33, P < 0.001), although amyl nitrite was of borderline significance (HR = 1.26, CI = 0.98-1.62, P = 0.074). The association between drug use and increased risk of HIV infection was strongest for drugs used specifically to enhance sexual pleasure, particularly OEM. The risk of infection was substantially increased when both OEM and methamphetamine were used. Within more "adventurous" gay community subcultures, the interconnectedness of sexual behavior and drug use may be key to understanding HIV risk and is an appropriate priority in HIV-prevention efforts in this population.