HIV Among MSM and Heterosexual Women in the United States: An Ecologic Analysis.

BACKGROUND: Phylogenetic studies show links between heterosexual women and men who have sex with men (MSM) that are more numerous than from heterosexual men to women suggesting that HIV infections among heterosexual women may stem from MSM. Poor communities have been associated with high rates of HIV among heterosexual women. Our analysis investigates potential transmission of HIV between MSM and female heterosexuals. METHODS: National HIV Behavioral Surveillance data describe transmission risk behaviors of MSM, and HIV case reporting data describe the percentages of cases that are attributed to transmission risk categories. We examined correlations between the percentages of men who were MSM who also have sex with women and female heterosexual cases. We also examined census data to characterize each city in terms of poverty level and race/ethnicity makeup. RESULTS: There was a high correlation (0.93) between the percentage of reported living HIV cases attributed to male heterosexual contact and female heterosexual contact and a moderate nonsignificant correlation (0.49) between the percentage of MSM who were men who have sex with men and women (MSMW) in National HIV Behavioral Surveillance and the percentage of reported cases that were attributed to female heterosexual contact suggesting some potential overlap. Cities with high levels of poverty and African American/Black residents had higher levels of MSMW and higher levels of heterosexual female cases. CONCLUSIONS: Addressing HIV in cities with high levels of MSMW may have the dual effect of improving the health of MSM populations that have a high burden of HIV and to improve the health of their larger communities.

Awareness, Willingness, and Use of Pre-exposure Prophylaxis Among Men Who Have Sex With Men in Washington, DC and Miami-Dade County, FL: National HIV Behavioral Surveillance, 2011 and 2014.

INTRODUCTION: Despite the effectiveness of oral pre-exposure prophylaxis (PrEP) for HIV prevention, knowledge, and uptake of this new prevention intervention over time has not been fully studied. Using NHBS data from 2 urban areas highly impacted by HIV, we examined awareness, use, and willingness to use daily oral PrEP and factors associated with willingness to take oral PrEP among men who have sex with men (MSM) over time. METHODS: MSM from Washington, DC and Miami, FL were recruited in 2011 and 2014 using venue-based sampling. Participants completed behavioral surveys and HIV testing. Awareness, use, and willingness to use oral PrEP were examined. Demographic and behavioral correlates of being "very likely" to use PrEP in 2011 and 2014 were assessed. RESULTS: PrEP awareness increased from 2011 to 2014 in both cities (DC: 39.1%-73.8% and Miami: 19.4%-41.2%), but use remained low in 2014 (DC: 7.7%; Miami: 1.4%). Being very likely to use PrEP decreased over time in DC (61%-48%), but increased in Miami (48%-60%). In DC, minority race was associated with increased odds of being very likely to use PrEP, whereas reduced odds of being very likely to use PrEP was observed for MSM with 1 or 2-5 partners versus having 6+ partners. In Miami, a higher proportion of white versus Hispanic MSM reported being very likely to use PrEP in 2011, but this observation was reversed in 2014. CONCLUSION: Geographic differences in awareness, use, and willingness to use PrEP indicate that innovative strategies are needed to educate MSM about this effective prevention strategy.

Incident Infection and Resistance Mutation Analysis of Dried Blood Spots Collected in a Field Study of HIV Risk Groups, 2007-2010.

OBJECTIVE: To assess the utility of cost-effective dried blood spot (DBS) field sampling for incidence and drug resistance surveillance of persons at high risk for HIV infection. METHODS: We evaluated DBS collected in 2007-2010 in non-clinical settings by finger-stick from HIV-positive heterosexuals at increased risk of HIV infection (n = 124), men who have sex with men (MSM, n = 110), and persons who inject drugs (PWID, n = 58). Relative proportions of recent-infection findings among risk groups were assessed at avidity index (AI) cutoffs of ≤25%, ≤30%, and ≤35%, corresponding to an infection mean duration of recency (MDR) of 220.6, 250.4, and 278.3 days, respectively. Drug resistance mutation prevalence was compared among the risk groups and avidity indices. RESULTS: HIV antibody avidity testing of all self-reported ARV-naïve persons (n = 186) resulted in 9.7%, 11.3% and 14.0% with findings within the 221, 250, and 278-day MDRs, respectively. The proportion of ARV-naïve MSM, heterosexuals, and PWID reporting only one risk category who had findings below the suggested 30% AI was 23.1%, 6.9% and 3.6% (p<0.001), respectively. MSM had the highest prevalence of drug resistance and the only cases of transmitted multi-class resistance. Among the ARV-experienced, MSM had disproportionately more recent-infection results than did heterosexuals and PWID. CONCLUSIONS: The disproportionately higher recent-infection findings for MSM as compared to PWID and heterosexuals increased as the MDR window increased. Unreported ARV use might explain greater recent-infection findings and drug resistance in this MSM population. DBS demonstrated utility in expanded HIV testing; however, optimal field handling is key to accurate recent-infection estimates.

Using High-Impact HIV Prevention to Achieve the National HIV/AIDS Strategic Goals in Miami-Dade County, Florida: A Case Study.

: In response to the release of the National HIV/AIDS Strategy, the Centers for Disease Control and Prevention developed the "Enhanced Comprehensive HIV Prevention Planning" project, which provided support to health departments in 12 Metropolitan Statistical Areas with the highest AIDS prevalence to strengthen local HIV programs. We describe a case study of how 1 Metropolitan Statistical Area, Miami-Dade County, developed and implemented a locally tailored plan. Examples include actions to reinforce local partnerships and identify neighborhoods with highest unmet needs, an improved condom distribution system to assist local HIV care providers, collaboration with local stakeholders to establish a new walk-in center for transgender client needs, and overcoming incompatibilities in health department and Ryan White Program computer record systems to facilitate faster and more efficient patient services. These examples show how jurisdictions both within Florida and elsewhere can create low-cost and sustainable activities tailored to improve local HIV prevention needs.

A comparison of syringe disposal practices among injection drug users in a city with versus a city without needle and syringe programs.

BACKGROUND: The United States (U.S.) approved use of federal funds for needle and syringe programs (NSPs) in December 2009. This study compares syringe disposal practices in a U.S. city with NSPs to a U.S. city without NSPs by examining the prevalence of improperly discarded syringes in public places and the self-reported syringe disposal practices of injection drug users (IDUs) in the two cities. METHODS: We conducted visual inspection walkthroughs in a random sample of the top-quartile of drug-affected neighborhoods in San Francisco, California (a city with NSPs) and Miami, Florida (a city without NSPs). We also conducted quantitative interviews with adult IDUs in San Francisco (N=602) and Miami (N=448). RESULTS: In the visual inspections, we found 44 syringes/1000 census blocks in San Francisco, and 371 syringes/1000 census blocks in Miami. Survey results showed that in San Francisco 13% of syringes IDUs reported using in the 30 days preceding the study interviews were disposed of improperly versus 95% of syringes by IDUs in Miami. In multivariable logistic regression analysis, IDUs in Miami had over 34 times the adjusted odds of public syringe disposal relative to IDUs in San Francisco (adjusted odds ratio=34.2, 95% CI=21.92, 53.47). CONCLUSIONS: We found eight-fold more improperly disposed syringes on walkthroughs in the city without NSPs compared to the city with NSPs, which was corroborated by survey data. NSPs may help IDUs dispose of their syringes safely in cities with large numbers of IDUs.

HIV prevention and transmission myths among heterosexually active adults in low-income areas of South Florida.

Misconceptions about HIV transmission and prevention may inhibit individuals' accurate assessment of their level of risk. We used venue-based sampling to conduct a cross-sectional study of heterosexually active adults (N = 1,221) within areas exhibiting high poverty and HIV/AIDS rates in Miami-Dade and Broward counties in 2007. Two logistic regression analyses identified correlates of holding inaccurate beliefs about HIV transmission and prevention. Belief in incorrect HIV prevention methods (27.2%) and modes of transmission (38.5%) was common. Having at least one incorrect prevention belief was associated with being Hispanic compared to white (non-Hispanic), being depressed, and not knowing one's HIV status. Having at least one incorrect transmission belief was associated with being younger, heavy alcohol use, being depressed, not having seen a physician in the past 12 months, and not knowing one's HIV status. Among low-income heterosexuals, HIV prevention and transmission myths are widespread. Debunking them could have HIV prevention value.

HIV/AIDS complacency and HIV infection among young men who have sex with men, and the race-specific influence of underlying HAART beliefs.

BACKGROUND: Among men who have sex with men (MSM) in the United States, the influence of HIV/AIDS complacency and beliefs about the efficacy of highly active antiretroviral therapy (HAART) on HIV-infection risk is unknown. METHODS: We analyzed data from a 1998-2000 cross-sectional 6-city survey of 1575 MSM aged 23 to 29 years who had never tested for HIV or had last tested HIV-negative to assess these plausible influences overall and by race/ethnicity. FINDINGS: Measured as strong endorsement for reduced HIV/AIDS concern due to HAART, HIV/AIDS complacency was associated with reporting ≥10 male sex partners (odds ratio [OR], 2.94; 95% confidence interval [CI], 2.12-4.07), unprotected anal intercourse with an HIV-positive or HIV-unknown-status male partner (OR, 2.06; 95% CI, 1.51-2.81), and testing HIV-positive (adjusted OR [AOR], 2.35; 95% CI, 1.38-3.98). Strong endorsement of the belief that HAART mitigates HIV/AIDS severity was more prevalent among black (21.8%) and Hispanic (21.3%) than white (9.6%) MSM (P < 0.001), and was more strongly associated with testing HIV-positive among black (AOR, 4.65; 95% CI, 1.97-10.99) and Hispanic (AOR, 4.12; 95% CI, 1.58-10.70) than white (AOR, 1.62; 95% CI, 0.64-4.11) MSM. CONCLUSIONS: Young MSM who are complacent about HIV/AIDS because of HAART may be more likely to engage in risk behavior and acquire HIV. Programs that target HIV/AIDS complacency as a means to reduce HIV incidence among young MSM should consider that both the prevalence of strong HAART-efficacy beliefs and the effects of these beliefs on HIV-infection risk might differ considerably by race/ethnicity.

A plausible causal model of HAART-efficacy beliefs, HIV/AIDS complacency, and HIV-acquisition risk behavior among young men who have sex with men.

Despite considerable research, the causal relationship remains unclear between HIV/AIDS complacency, measured as reduced HIV/AIDS concern because of highly active antiretroviral therapy (HAART), and HIV risk behavior. Understanding the directionality and underpinnings of this relationship is critical for programs that target HIV/AIDS complacency as a means to reduce HIV incidence among men who have sex with men (MSM). This report uses structural equation modeling to evaluate a theory-based, HIV/AIDS complacency model on 1,593 MSM who participated in a venue-based, cross-sectional survey in six U.S. cities, 1998-2000. Demonstrating adequate fit and stability across geographic samples, the model explained 15.0% of the variance in HIV-acquisition behavior among young MSM. Analyses that evaluated alternative models and models stratified by perceived risk for HIV infection suggest that HIV/AIDS complacency increases acquisition behavior by mediating the effects of two underlying HAART-efficacy beliefs. New research is needed to assess model effects on current acquisition risk behavior, and thus help inform prevention programs designed to reduce HIV/AIDS complacency and HIV incidence among young MSM.

HIV seropositivity and correlates of infection among heterosexually active adults in high-risk areas in South Florida.

The U.S. HIV/AIDS epidemic disproportionately impacts lower-income populations. We conducted a cross-sectional study of heterosexually active adults (N = 1076) in areas with high poverty and HIV/AIDS rates in South Florida in 2007. Using venue-based sampling, anonymous interviews and HIV tests were conducted at randomly selected venues (primarily retail businesses not associated with risk behaviors). The sample's HIV infection rate was 7.1%. Half (52.2%) of the infections were previously undiagnosed. Our findings underscore the impact of social and environmental factors on HIV risk, as well as the need to increase and optimize HIV testing and other prevention services.

Crystal methamphetamine use and sexual risk behaviors among HIV-positive and HIV-negative men who have sex with men in South Florida.

Using data collected through venue-based sampling in South Florida from 2004 to 2005 as part of the Centers for Disease Control and Prevention-funded National HIV Behavioral Surveillance Among Men Who Have Sex with Men, we estimate the prevalence of crystal methamphetamine use and its association with high-risk sexual behaviors among a large and diverse sample of men who have sex with men (MSM) residing in South Florida. We also examine how these associations differ between HIV-positive and HIV-negative men. Bivariate analyses were used to assess the characteristics of study participants and their sexual risk behaviors by drug use and self-reported HIV status group. Of 946 MSM participants in South Florida, 18% reported crystal methamphetamine use in the past 12 months. Regardless of self-reported HIV status, crystal methamphetamine users were more likely to report high-risk sexual behaviors, an increased number of non-main sex partners, and being high on drugs and/or alcohol at last sex act with a non-main partner. Our findings indicate that crystal methamphetamine use is prevalent among the MSM population in South Florida, and this prevalence rate is similar, if not higher, than that found in US cities that have been long recognized for having a high rate of crystal methamphetamine use among their MSM populations. Notably, the use of crystal methamphetamine among both HIV-positive and HIV-negative MSM is associated with increased HIV-related risk behaviors.

Detecting acute human immunodeficiency virus infection using 3 different screening immunoassays and nucleic acid amplification testing for human immunodeficiency virus RNA, 2006-2008.

BACKGROUND: The yield of nucleic acid amplification testing (NAAT) after routine screening for human immunodeficiency virus (HIV) antibody to detect acute HIV infection (AHI) may vary with different HIV-antibody assays. METHODS: From April 24, 2006, through March 28, 2008, patients underwent routine HIV-antibody screening using a first-generation assay at 14 county sexually transmitted disease (STD) clinics and 1 community clinic serving homosexual patients in Los Angeles; using a second-generation rapid test at 3 municipal STD clinics in New York; and using a third-generation assay at 80 public health clinics in Florida. To identify AHI, seronegative specimens were pooled for NAAT, followed by individual NAAT of specimens with positive findings. All AHI samples screened by first- and second-generation assays also underwent third-generation testing. RESULTS: We screened 37 012 persons using NAAT after first-generation testing; 35 AHIs were identified, increasing HIV case detection by 8.2%. After a second-generation rapid test, 6547 persons underwent NAAT; 7 AHIs were identified, increasing HIV case detection by 24.1%. After third-generation testing, 54 948 persons underwent NAAT; 12 AHI cases were identified, increasing HIV case detection by 1.4%. Overall, pooled NAAT after negative third-generation test results detected 26 AHI cases, increasing HIV case detection by 2.2%. Most of the AHI cases from Los Angeles (26 of 35 [74%]) were identified at the community clinic where NAAT after third-generation testing increased HIV case detection by 11.9%. CONCLUSIONS: Pooled NAAT after third-generation testing increases HIV case detection, especially in venues of high HIV seropositivity. Therefore, targeted AHI screening using pooled NAAT after third-generation testing may be most effective, warranting a cost-benefit analysis.

Costs of voluntary rapid HIV testing and counseling in jails in 4 states--advancing HIV Prevention Demonstration Project, 2003-2006.

OBJECTIVE: To assess the costs of rapid human immunodeficiency virus (HIV) testing and counseling to identify new diagnoses of HIV infection among jail inmates. STUDY DESIGN: We obtained program costs and testing outcomes from rapid HIV testing and counseling services provided in jails from March 1, 2004, through February 28, 2005, in Florida, Louisiana, New York, and Wisconsin. We obtained annual program delivery costs-fixed and variable costs-from each project area. We estimated the average cost of providing counseling and testing to HIV-negative and HIV-infected inmates and estimated the cost per newly diagnosed HIV infection. RESULTS: In the 4 project areas, 17,433 inmates (range, 2185-6463) were tested: HIV infection was diagnosed for 152 inmates (range, 4-81). The average cost of testing ranged from $29.46 to $44.98 for an HIV-negative inmate and from $71.37 to $137.72 for an HIV-infected inmate. The average cost per newly diagnosed HIV infection ranged from $2,451 to $25,288. Variable costs were 61% to 86% of total costs. CONCLUSION: The cost of identifying jail inmates with newly diagnosed HIV infection by using rapid HIV testing varied according to the prevalence of undiagnosed HIV infection among inmates tested in project areas. Variations in the cost of testing HIV-negative and HIV-infected inmates were because of the differences in wages, travel to the jails, and the amount of time spent on counseling and testing. Program managers can use these data to gauge the cost of initiating counseling and testing programs in jails or to streamline current programs.

Voluntary rapid human immunodeficiency virus (HIV) testing in jails.

OBJECTIVES: To provide human immunodeficiency virus (HIV) rapid testing to persons in jails, identify previously undiagnosed cases of HIV infection, and refer HIV-infected inmates to care, treatment, and prevention services. DESIGN: Four state health departments (Florida, Louisiana, New York, and Wisconsin) collaborated with jails to implement stand-alone voluntary rapid HIV testing programs. Inmates requested or were referred by medical staff for rapid HIV testing. HIV testing was provided by the health department, correctional facility, or a community-based organization. Inmates whose rapid test was reactive were offered confirmatory testing, medical evaluation, prevention services, and discharge planning. RESULTS: From December 2003 through May 2006, rapid HIV testing was provided to 33,211 inmates, more than 99.9% of whom received their test results. Most of the inmates tested were male (79%), black (58%), and less than 35 years of age (60%). A total of 440 (1.3%) rapid HIV tests were reactive, and 409 (1.2%) of the results were confirmed positive. The testing programs identified 269 (0.8%) previously undiagnosed cases of HIV infection. In the multivariate analyses, new HIV diagnoses were associated with race/ethnicity, report of risky behaviors, and with no report of HIV risk behavior. Almost 40% of diagnoses were for inmates whose only reported risk was heterosexual contact. CONCLUSIONS: Rapid HIV testing in jails identified a considerable number of previously undiagnosed cases of HIV infection. Rapid HIV testing should be available to all inmates, regardless of whether inmates reported HIV risky behaviors.

HIV prevention services received at health care and HIV test providers by young men who have sex with men: an examination of racial disparities.

We investigated whether there were racial/ethnic differences among young men who have sex with men (MSM) in their use of, perceived importance of, receipt of, and satisfaction with HIV prevention services received at health care providers (HCP) and HIV test providers (HTP) that explain racial disparities in HIV prevalence. Young men, aged 23 to 29 years, were interviewed and tested for HIV at randomly sampled MSM-identified venues in six U.S. cities from 1998 through 2000. Analyses were restricted to five U.S. cities that enrolled 50 or more black or Hispanic MSM. Among the 2,424 MSM enrolled, 1,522 (63%) reported using a HCP, and 1,268 (52%) reported having had an HIV test in the year prior to our interview. No racial/ethnic differences were found in using a HCP or testing for HIV. Compared with white MSM, black and Hispanic MSM were more likely to believe that HIV prevention services are important [respectively, AOR, 95% confidence interval (CI): 3.0, 1.97 to 4.51 and AOR, 95% CI: 2.7, 1.89 to 3.79], and were more likely to receive prevention services at their HCP (AOR, 95% CI: 2.5, 1.72 to 3.71 and AOR, 95% CI: 1.7, 1.18 to 2.41) and as likely to receive counseling services at their HTP. Blacks were more likely to be satisfied with the prevention services received at their HCP (AOR, 95% CI: 1.7, 1.14 to 2.65). Compared to white MSM, black and Hispanic MSM had equal or greater use of, perceived importance of, receipt of, and satisfaction with HIV prevention services. Differential experience with HIV prevention services does not explain the higher HIV prevalence among black and Hispanic MSM.

The Young Men's Survey phase II: hepatitis B immunization and infection among young men who have sex with men.

OBJECTIVES: We measured the prevalence of hepatitis B virus (HBV) immunization and HBV infection among men aged 23 to 29 years who have sex with men. METHODS: We analyzed data from 2834 men who have sex with men in 6 US metropolitan areas. Participants were interviewed and tested for serologic markers of immunization and HBV infection in 1998 through 2000. RESULTS: Immunization prevalence was 17.2%; coverage was 21.0% among participants with private physicians or health maintenance organizations and 12.6% among those with no source of health care. Overall, 20.6% had markers of HBV infection, ranging from 13.7% among the youngest to 31.0% among the oldest participants. Among those susceptible to HBV, 93.5% had regular sources of health care, had been tested for HIV, or had been treated for a sexually transmitted disease. CONCLUSIONS: Although many young men who have sex with men have access to health care, most are not immunized against HBV. To reduce morbidity from HBV in this population, providers of health care, including sexually transmitted disease and HIV prevention services, should provide vaccinations or referrals for vaccination.

Men who have sex with men: estimated population sizes and mortality rates by race/ethnicity, Miami-Dade County, Florida.

BACKGROUND: Estimated numbers of men who have sex with men (MSM) by race/ethnicity and mortality rates among such MSM with HIV/AIDS are unavailable. This hampers efficient targeting of HIV/AIDS prevention and care resources. METHODS: An existing estimation methodology was adapted to develop MSM population estimates by race/ethnicity for Miami-Dade County, Florida. We ascertained and characterized deaths that occurred during 2003 to 2005 among MSM HIV/AIDS cases, matching HIV/AIDS surveillance and vital statistics registries. We calculated estimated average annual racial/ethnic-specific mortality rates and rate ratios (RRs) among MSM HIV/AIDS cases. RESULTS: An estimated 63,020 men aged > or =18 years in the county are MSM (7.5% of all men aged > or =18 years; point estimate). Among 754 MSM HIV/AIDS deaths, point-estimate mortality rates per 100,000 MSM were higher for blacks (733.5) than for whites (229.2) (P < 0.01) and Hispanics (360.5) (P < 0.01). The best estimate of the black/white MSM mortality RR among HIV/AIDS cases was 3.20:1 (P < 0.01); for Hispanic/white MSM, it was 1.57:1 (P < 0.01). Sensitivity analyses suggested the estimates were reasonably robust to biases that we examined. CONCLUSIONS: Black and Hispanic MSM were more likely to die with HIV/AIDS than white MSM. Plausible racial/ethnic-specific MSM population and mortality rate estimates can inform effective HIV/AIDS prevention efforts and program planning.

Perceptions of lifetime risk and actual risk for acquiring HIV among young men who have sex with men.

Among young men who have sex with men (MSM) surveyed in six US cities, we evaluated the magnitude and correlates of perceived lifetime risk for acquiring HIV, and missed opportunities to increase risk perception by providers of health-care and HIV-testing services. Overall, approximately one quarter of young MSM perceived themselves at moderate/high risk for acquiring HIV. Adjusting for demographic, prior testing, and behavioral characteristics, moderate/high perceived risk had the strongest association with unrecognized HIV infection. However, half of the 267 young MSM with unrecognized infection perceived themselves at low lifetime risk for acquiring HIV, and many young MSM with low-risk perception reported considerable risk behaviors. Providers of health-care and HIV-testing services missed opportunities to assess risks and recommend testing for young MSM. To increase HIV testing, prevention providers should intensify efforts to assess, and to increase when needed, perceptions of lifetime risks for acquiring HIV among young MSM.

Characteristics of persons with recently acquired HIV infection: application of the serologic testing algorithm for recent HIV seroconversion in 10 US cities.

BACKGROUND: Information about the characteristics of persons whose HIV diagnosis was made soon after infection contributes to a better understanding of the HIV epidemic and to appropriate targeting of care and prevention efforts. METHODS: In 10 US cities from 1997 through 2001, specimens from consenting persons for whom a diagnosis of HIV was made within the past 12 months in were tested using the serologic testing algorithm for recent HIV seroconversion. The characteristics of those whose HIV diagnosis occurred within 170 days (on average) from seroconversion were identified. RESULTS: For 191 (20%) of the 964 participants, an HIV diagnosis was made during the period of recent infection. These diagnoses of recent infection were made more frequently among men (21.7%), whites (29.3%), men who have sex with men (25.5%), persons with a known HIV-infected partner (24.9%), and persons with a diagnosis of gonorrhea made in the 12 months before interview (27.0%). Recent infection was diagnosed less frequently among African Americans (15.5%), Latinos (15.5), and heterosexual men (14.7%) and women (14.4%). CONCLUSIONS: To increase early diagnosis of HIV, HIV testing should be more routinely offered to persons with a recent history of sexually transmitted diseases and to African Americans and Latinos in a variety of settings.

Age shift in patterns of injection drug use among the HIV/AIDS population in Miami-Dade County, Florida.

Analysis of HIV exposure category for 20,034 persons in three age groups (13-29, 30-49, 50 and over) who were alive through 2003 and had been reported to the Florida Department of Health with HIV or AIDS in Miami-Dade County, Florida, found that having a history of injection drug use increases with increasing age (p < .001). Consideration of age-specific HIV risk profiles has implications for primary and secondary HIV prevention interventions, planning, and policy.

Unintentional HIV exposures from young men who have sex with men who disclose being HIV-negative.

OBJECTIVE: To evaluate the proportion of new sexual partners potentially exposed to HIV from young MSM who disclosed being HIV-negative. DESIGN: Cross-sectional, observational study of men aged 23-29 years recruited from randomly sampled MSM-identified venues in six US cities. METHODS: Participants were interviewed and tested for HIV. Analyses were restricted to MSM who reported last testing HIV-negative and having one or more new partners in the prior 6 months. RESULTS: Of 1701 MSM who reported a total of 11 793 new partners, 1075 (63%) disclosed being HIV-negative to 4253 (36%) new partners before having sex with them for the first time. Of disclosers, 352 (33%) reported last testing HIV-negative > 1 year before their interview and 80 (7%) tested HIV-positive (HIV-infected unaware). By race, 24% of black, 5% of Hispanic, and 3% of white disclosers tested HIV-positive. Of the 4253 new partners, 296 (7%) were partners of the 80 HIV-infected unaware MSM. By race, 22% of new partners of black, 3% of new partners of Hispanic, and 4% of new partners of white MSM, were partners of HIV-infected unaware MSM who disclosed being HIV-negative. CONCLUSIONS: Many new sex partners may be unintentionally exposed to HIV from young MSM, particularly those who are black and who disclose being HIV-negative based on an earlier test. Young MSM should test for HIV more frequently and consistently use condoms with all partners unless they are in a mutually monogamous relationship in which both partners have tested HIV-negative at least 3 months since their last potential HIV exposure.