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Dive into the research topics where Duncan A. MacKellar is active.

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Featured researches published by Duncan A. MacKellar.


Public Health Reports | 2007

Surveillance of HIV risk and prevention behaviors of men who have sex with men : A national application of venue-based, time-space sampling

Duncan A. MacKellar; Kathleen M. Gallagher; Teresa Finlayson; Travis Sanchez; Amy Lansky; Patrick S. Sullivan

In collaboration with the Centers for Disease Control and Prevention, participating state and local health departments, universities, and community-based organizations applied venue-based, time-space sampling methods for the first wave of National HIV Behavioral Surveillance of men who have sex with men (NHBS-MSM). Conducted in 17 metropolitan areas in the United States and Puerto Rico from November 2003 through April 2005, NHBS-MSM methods included: (1) formative research to learn the venues, times, and methods to recruit MSM; (2) monthly sampling frames of eligible venues and day-time periods that met attendance, logistical, and safety criteria; and (3) recruitment of participants in accordance with randomly generated venue calendars. Participants were interviewed on HIV risk and prevention behaviors, referred to care when needed, and compensated for their time. By identifying the prevalence and trends of HIV risk and prevention behaviors, NHBS-MSM data may be used at local, state, and federal levels to help obtain, direct, and evaluate HIV prevention resources for MSM.


Journal of Acquired Immune Deficiency Syndromes | 2004

Associations of Race/Ethnicity With HIV Prevalence and HIV-Related Behaviors Among Young Men Who Have Sex With Men in 7 Urban Centers in the United States

Nina T. Harawa; Sander Greenland; Trista Bingham; Denise F. Johnson; Susan D. Cochran; William E. Cunningham; David D. Celentano; Beryl A. Koblin; Marlene LaLota; Duncan A. MacKellar; William McFarland; Douglas Shehan; Sue Stoyanoff; Hanne Thiede; Lucia V. Torian; Lucia A. Valleroy

Abstract:Using data from a multisite venue-based survey of male subjects aged 15 to 22 years, we examined racial/ethnic differences in demographics, partner type, partner type-specific condom use, drug use, and HIV prevalence in 3316 US black, multiethnic black, Latino, and white men who have sex with men (MSM). We further estimated associations of these factors with HIV infection and their influence on racial/ethnic disparities in HIV prevalence. HIV prevalences were 16% for both black and multiethnic black participants, 6.9% for Latinos, and 3.3% for whites. Paradoxically, potentially risky sex and drug-using behaviors were generally reported most frequently by whites and least frequently by blacks. In a multiple logistic regression analysis, positive associations with HIV included older age, being out of school or work, sex while on crack cocaine, and anal sex with another male regardless of reported condom use level. Differences in these factors did not explain the racial/ethnic disparities in HIV prevalence, with both groups of blacks experiencing more than 9 times and Latinos experiencing approximately twice the fully adjusted odds of infection compared with whites. Understanding racial/ethnic disparities in HIV risk requires information beyond the traditional risk behavior and partnership type distinctions. Prevention programs should address risks in steady partnerships, target young men before sexual initiation with male partners, and tailor interventions to men of color and of lower socioeconomic status.


Journal of Acquired Immune Deficiency Syndromes | 2005

Unrecognized HIV infection, risk behaviors, and perceptions of risk among young men who have sex with men: opportunities for advancing HIV prevention in the third decade of HIV/AIDS.

Duncan A. MacKellar; Linda A. Valleroy; Gina M. Secura; Stephanie Behel; Trista Bingham; David D. Celentano; Beryl A. Koblin; Marlene LaLota; William McFarland; Douglas Shehan; Hanne Thiede; Lucia V. Torian; Robert S. Janssen

This study evaluated the magnitude and distribution of unrecognized HIV infection among young men who have sex with men (MSM) and of those with unrecognized infection, the prevalence and correlates of unprotected anal intercourse (UAI), perceived low risk for infection, and delayed HIV testing. MSM aged 15-29 years were approached, interviewed, counseled, and tested for HIV at 263 randomly sampled venues in 6 US cities from 1994-2000. Of 5649 MSM participants, 573 (10%) tested positive for HIV. Of these, 91% of black, 69% of Hispanic, and 60% of white MSM (77% overall) were unaware of their infection. The 439 MSM with unrecognized infection reported a total of 2253 male sex partners in the previous 6 months; 51% had UAI; 59% perceived that they were at low risk for being infected; and 55% had not tested in the previous year. The HIV epidemic among MSM in the United States continues unabated, in part, because many young HIV-infected MSM are unaware of their infection and unknowingly expose their partners to HIV. To advance HIV prevention in the third decade of HIV/AIDS, prevention programs must reduce unrecognized infection among young MSM by increasing the demand for and availability of HIV testing services.


American Journal of Public Health | 2003

Regional Patterns and Correlates of Substance Use Among Young Men Who Have Sex With Men in 7 US Urban Areas

Hanne Thiede; Linda A. Valleroy; Duncan A. MacKellar; David D. Celentano; Wesley Ford; Holly Hagan; Beryl A. Koblin; Marlene LaLota; William McFarland; Douglas Shehan; Lucia V. Torian

OBJECTIVES We sought to characterize substance use patterns in young men who have sex with men (MSM) in 7 US urban areas and sociodemographic characteristics and history associated with such use. METHODS We examined data collected from 1994 through 1998 in a venue-based, cross-sectional survey. RESULTS Among the 3492 participants, 66% reported use of illicit drugs; 28%, use of 3 or more drugs; 29%, frequent drug use (once a week or more); and 4%, injection drug use. These practices were more common among participants who were White, self-identified as bisexual or heterosexual, had run away, or had experienced forced sex. CONCLUSIONS Effective drug prevention and treatment programs addressing local drug-use patterns and associated factors are urgently needed for young MSM, a population with a high rate of illicit drug use.


Sexually Transmitted Diseases | 2006

Associations between substance use and sexual risk among very young men who have sex with men.

David D. Celentano; Linda A. Valleroy; Frangiscos Sifakis; Duncan A. MacKellar; John B. Hylton; Hanne Thiede; Willi McFarland; Douglas Shehan; Susan Stoyanoff; Marlene LaLota; Beryl A. Koblin; Mitchell H. Katz; Lucia V. Torian

Objective: To determine if an association exists in young men who have sex with men (MSM) between being under the influence of alcohol or drugs during sex and participation in sexual behaviors which increase the risk of human immunodeficiency virus (HIV). Study Design: A total of 3492 young MSM were interviewed through the Young Men’s Survey, an anonymous, cross-sectional, multisite, venue-based survey conducted from 1994 through 1998 at 194 public venues frequented by MSM aged 15 to 22 years in 7 US cities. Results: The majority of young MSM reported both receptive and insertive anal intercourse, and of these, approximately half reported not using condoms. Report of unprotected receptive anal intercourse at least once in the prior 6 months was associated with being under the influence of alcohol (adjusted odds ratio [AOR] = 1.5; 95% confidence interval [CI] = 1.2–1.8), cocaine (AOR = 1.6; 95% CI = 1.1–2.2), amphetamines (AOR = 1.5; 95% CI = 1.1–2.0) or marijuana during sex (AOR = 1.3; 95% CI = 1.1–1.6). Report of unprotected insertive anal intercourse at least once in the prior 6 months was associated with being under the influence of alcohol (AOR = 1.2; 95% CI = 1.0–1.5), cocaine (AOR = 1.5; 95% CI = 1.1–2.0) or amphetamines (AOR = 1.9; 95% CI = 1.4–2.6). Conclusions: HIV prevention strategies for young MSM need to incorporate substance use risk reduction.


Journal of Acquired Immune Deficiency Syndromes | 2000

Very young gay and bisexual men are at risk for HIV infection: the San Francisco Bay Area Young Men's Survey II.

Craig R. Waldo; William McFarland; Mitchell H. Katz; Duncan A. MacKellar; Linda A. Valleroy

Objectives: To compare HIV seroprevalence and sexual risk behavior among very young gay and bisexual men (aged 15‐17 years) and their older counterparts (aged 18‐22 years). To examine drug‐use patterns and correlates of sexual risk behavior in both of these age groups. Design and Methods: An interviewer‐administered cross‐sectional survey of 719 gay and bisexual males between 15 and 22 years old was conducted through a venuebased sampling design. Blood specimens were collected and tested for HIV antibodies, hepatitis B, and syphilis. Interviews assessed sexual and drug‐use behavior as well as psychosocial variables believed to be related to sexual risk‐taking, including self‐acceptance of gay or bisexual identity, perceptions of peer norms concerning safer sex, and perceptions of the ability to practice safer sex (safer sex self‐efficacy). Results: Of the 719 participants, 100 (16.2%) were aged between 15 and 17 years. HIV seroprevalence was somewhat lower among those aged 15 to 17 years (2.0%) compared with those aged 18 to 22 years (6.8%). Overall, the prevalence of hepatitis‐B core antibody was significantly lower in the younger age group (5.0%) than in the older group (14.1%). The men aged 15 to 17 years used alcohol, ecstasy, and heroin less frequently than those aged 18 to 22 years. The age groups did not differ in the proportion of men who reported any unprotected anal intercourse in the previous 6 months (31.2%). In both age groups, use of amphetamines, ecstasy, and amyl nitrate was associated with unprotected anal intercourse. Self‐acceptance of gay or bisexual identity was related to less sexual risk for those aged 15 to 17 years. In both age groups, greater safer sex self‐efficacy was linked to less HIV sexual risk‐taking. In the younger group, perceptions of peer norms that support safer sex were related to less risk behavior. Conclusions: Very young gay and bisexual men engage in unprotected anal sex at rates comparable with those for their somewhat older counterparts, raising serious concern over their risk of acquiring HIV infection. To prevent seroconversions, interventions must target those <18 years of age, and prevention programs should address the use of certain drugs in relation to sex and sexual risk‐taking. To be most effective, programs should develop innovative communication strategies to take into account lack of self‐acceptance of gay or bisexual identity and low self‐efficacy for practicing safer sex.


AIDS | 2000

High prevalence of HIV infection among young men who have sex with men in New York City.

Beryl A. Koblin; Lucia V. Torian; Vince Guilin; Leigh Ren; Duncan A. MacKellar; Linda A. Valleroy

ObjectiveTo determine the prevalence of HIV infection and risk behaviors among young men who have sex with men (MSM) aged 15–22 years in New York City. DesignAn anonymous cross-sectional survey. MethodsThe 1998 Young Mens Survey in New York City (YMS–NYC), was a multistage probability survey of 541 MSM aged 15–22 years who attend public venues. After identification of venues and their associated high attendance time periods, random samples of venues and time periods were selected on a monthly basis. At each sampling event, potential participants were approached to determine eligibility. Eligible and willing men were interviewed, counselled and had a blood specimen drawn. ResultsBetween December 1997 and September 1998, 115 sampling events were conducted. Of 612 men enrolled, 541 reported ever having had sex with a male partner. The HIV seroprevalence among the 541 MSM sampled was 12.1%. The HIV seroprevalence was 18.4% among African-Americans, 16.7% among persons of mixed race, 8.8% among Latino individuals and 3.1% among white men. HIV seroprevalence was 5.0% among 15–18 year olds and 16.4% among 19–22 year olds. A total of 65.5% of MSM were susceptible to hepatitis B virus infection (HBV). Almost half (46.1%) of the men reported unprotected anal sex in the previous 6 months and 16.3% reported ever having had an STD. Multiple regression analyses found that being older, of mixed race, black or ever having had an STD was associated with being HIV antibody positive. ConclusionThese data identify a large subgroup of MSM in need of effective HIV and HBV primary and secondary prevention programs.


Sexually Transmitted Diseases | 2011

Reasons for not HIV testing, testing intentions, and potential use of an over-the-counter rapid HIV test in an internet sample of men who have sex with men who have never tested for HIV.

Duncan A. MacKellar; Su-I Hou; Christopher C. Whalen; Karen Samuelsen; Travis Sanchez; Amanda Smith; Damian Denson; Amy Lansky; Patrick S. Sullivan

Background: Correlates of main reasons for not HIV testing, HIV testing intentions, and potential use of an over-the-counter rapid HIV test (OTCRT) among men who have sex with men who have never tested for HIV (NTMSM) are unknown. Methods: We evaluated these correlates among 946 NTMSM from 6 US cities who participated in an internet-based survey in 2007. Findings: Main reasons for not testing were low perceived risk (32.2%), structural barriers (25.1%), and fear of testing positive (18.1%). Low perceived risk was associated with having fewer unprotected anal intercourse (UAI) partners and less frequent use of the internet for HIV information; structural barriers were associated with younger age and more UAI partners; fear of testing positive was associated with black and Hispanic race/ethnicity, more UAI partners, and more frequent use of the internet for HIV information. Strong testing intentions were held by 25.9% of all NTMSM and 14.8% of those who did not test because of low perceived risk. Among NTMSM who were somewhat unlikely, somewhat likely, and very likely to test for HIV, 47.4%, 76.5%, and 85.6% would likely use an OTCRT if it was available, respectively. Conclusions: Among NTMSM who use the internet, main reasons for not testing for HIV vary considerably by age, race/ethnicity, UAI, and use of the internet for HIV information. To facilitate HIV testing of NTMSM, programs should expand interventions and services tailored to address this variation. If approved, OTCRT might be used by many NTMSM who might not otherwise test for HIV.


JAMA Internal Medicine | 2010

Detecting Acute Human Immunodeficiency Virus Infection Using 3 Different Screening Immunoassays and Nucleic Acid Amplification Testing for Human Immunodeficiency Virus RNA, 2006-2008

Pragna Patel; Duncan A. MacKellar; Pat Simmons; Apurva Uniyal; Kathleen M. Gallagher; Berry Bennett; Timothy J. Sullivan; Alexis Kowalski; Monica M. Parker; Marlene LaLota; Peter R. Kerndt; Patrick S. Sullivan

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.


Journal of Acquired Immune Deficiency Syndromes | 2002

Repeat HIV testing, risk behaviors, and HIV seroconversion among young men who have sex with men: a call to monitor and improve the practice of prevention.

Duncan A. MacKellar; Linda A. Valleroy; Gina M. Secura; Brad Bartholow; William Mcfarland; Douglas Shehan; Wesley Ford; Marlene LaLota; David D. Celentano; Beryl A. Koblin; Lucia V. Torian; Thomas Perdue; Robert S. Janssen

&NA; Objectives: We compared recent risk behaviors and HIV seroconversion among young men who have sex with men (MSM) who were first‐time, infrequent, and repeat HIV testers. Methods: Male adolescents and young men aged 15 to 22 years were randomly sampled, interviewed, counseled, and tested for HIV at 194 gay‐identified venues in seven U.S. cities from 1994 through 1998. Analyses were restricted to MSM who reported having never tested or last tested HIV‐negative. Results: Of 3430 participants, 36% tested for the first time, 39% had tested infrequently (one or two times), and 26% had tested repeatedly (≥ three times). Compared with first‐time testers, repeat testers were more likely to report recent risk behaviors and to acquire HIV (7% versus 4%). Over 75% of repeat testers who seroconverted acquired HIV within 1 year of their last test. Compared with repeat testers, first‐time testers reported similar use of health care but delayed testing for nearly 2 additional years after initiating risk. Conclusions: Many young MSM soon acquire HIV after repeated use of HIV counseling and testing services. Providers must strengthen practices to identify, counsel, and test young MSM and provide enhanced behavioral interventions for those with persistent risks.

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Linda A. Valleroy

Centers for Disease Control and Prevention

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Gina M. Secura

Centers for Disease Control and Prevention

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Lucia V. Torian

New York City Department of Health and Mental Hygiene

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Marlene LaLota

Florida Department of Health

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Stephanie Behel

Centers for Disease Control and Prevention

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Douglas Shehan

University of Texas Southwestern Medical Center

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Robert S. Janssen

Centers for Disease Control and Prevention

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