Nguyen K. Tran (he/him), PhD, MPH is a social epidemiologist and postdoctoral scholar with The PRIDE Study at Stanford University School of Medicine. In his current role, he applies his training epidemiology, data science, and causal inference to conduct and support community-engaged research that addresses the health priorities of queer and transgender communities, with the goal of advancing health equity for these populations. This work includes examining the validity of gender identity and sexual orientation question sets in population-based surveys, evaluating social and structural influences on mental health, and understanding the spatial pattern of infectious diseases (e.g., HIV and mpox).

Boards, Advisory Committees, Professional Organizations

  • Member, Society for Epidemiologic Research (2018 - Present)

Professional Education

  • Doctor of Philosophy, Drexel University (2022)
  • Master of Public Health, Drexel University (2018)
  • Bachelor of Science, The University of Texas at Austin (2016)

Stanford Advisors

Lab Affiliations

All Publications

  • Geolocation to Identify Online Study-Eligible Gay, Bisexual, and Men who have Sex with Men in Philadelphia, Pennsylvania. Epidemiology (Cambridge, Mass.) Tran, N. K., Welles, S. L., Goldstein, N. D. 2023; 34 (4): 462-466


    BACKGROUND: Data collection and cleaning procedures to exclude bot-generated responses are used to maintain the data integrity of samples from online surveys. However, these procedures may be time-consuming and difficult to implement. Thus, we aim to evaluate the validity of a single-step geolocation algorithm for recruiting eligible gay, bisexual, and men who have sex with men in Philadelphia for an online study.METHODS: We used a 4-step approach, based on common practices for evaluating bot-generated and fraudulent responses, to assess the validity of participants' Qualtrics survey data as our referent standard. We then compared it to Qualtrics' single-step geolocation algorithm that used the MaxMind commercial database to map participants' Internet protocol address to their approximate location. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the single-step geolocation approach relative to the 4-step approach.RESULTS: There were 826 respondents who completed the survey and 440 (53%) were eligible for enrollment based on the 4-step approach. The single-step geolocation approach yielded a sensitivity of 91% (95% CI = 88%, 93%), specificity of 79% (95% CI = 74%, 83%), PPV of 83% (95% CI = 80%, 86%), and NPV of 88% (95% CI = 85%, 91%).CONCLUSIONS: Geolocation alone provided a moderately high level of agreement with the 4-step approach for identifying geographically eligible participants in the online sample, but both approaches may be subject to additional misclassification. Researchers may want to consider multiple procedures to ensure data integrity in online samples.

    View details for DOI 10.1097/EDE.0000000000001607

    View details for PubMedID 37255263

  • A Note on Pre-exposure prophylaxis (PrEP) preferences among women who inject drugs. Sexually transmitted diseases Miley, K. L., Tran, N. K., Elopre, L., Groves, A., Stockman, J. K., Bazzi, A. R., Carrico, A., Mazzella, S., Roth, A. M. 2023


    ABSTRACT: We informed women who inject drugs about different pre-exposure prophylaxis (PrEP) formulations; they then ranked their preferences. Daily oral PrEP was most preferred, followed by injectable PrEP and vaginal rings/gels, especially among women of color. Multiple PrEP options should be discussed with women who inject drugs to increase uptake.

    View details for DOI 10.1097/OLQ.0000000000001768

    View details for PubMedID 36728264

  • An Exploration of Racial Differences of Psychosocial Stressors and Their Association With Mental Health Between Asian and White Sexual Minority Men: The P18 Cohort Study ASIAN AMERICAN JOURNAL OF PSYCHOLOGY Tran, N. K., Le, T. P., Krause, K. D., Martino, R. J., Halkitis, P. N. 2023

    View details for DOI 10.1037/aap0000309

    View details for Web of Science ID 000909778200001



    Long-acting injectable pre-exposure prophylaxis (LAI-PrEP) was recently approved for HIV prevention as an alternative to daily oral PrEP. We explored preferences and attitudes toward LAI-PrEP among Black, Hispanic/Latino, and White gay, bisexual, and other men who have sex with men (GBM) using focus groups (n = 13) and in-depth interviews (n = 17). Participants expressed differing levels of interest in LAI-PrEP. While important benefits of LAI-PrEP included convenience, provider-facilitated PrEP discussion, and expansion of PrEP options, participants raised concerns about treatment efficacy and side effects, discomfort with needles/injections, cost, and frequency of clinic visits. Our findings highlight ongoing challenges with accessing HIV-prevention tools and provide guidance for developing strategies to enhance LAI-PrEP uptake among GBM.

    View details for Web of Science ID 000865610600002

    View details for PubMedID 36181495

  • State-level heterogeneity in associations between structural stigma and individual healthcare access: A multilevel analysis of transgender adults in the United States JOURNAL OF HEALTH SERVICES RESEARCH & POLICY Tran, N. K., Baker, K. E., Lett, E., Scheim, A. 2022: 13558196221123413


    State-level variation in how restrictive policies affect health care access for transgender populations has not been widely studied. Therefore, we assessed the association between structural stigma and four measures of individual health care access among transgender people in the United States, and the extent to which structural stigma explains state-level variability.Data were drawn from the 2015-2019 Behavioral Risk Factor Surveillance System and the Human Rights Campaign's State Equality Index. We calculated weighted proportions and conducted multilevel logistic regression of individual heterogeneity and discriminatory accuracy.An increase in the structural stigma score by one standard deviation was associated with lower odds of health care coverage (OR = 0.80; 95% CI: 0.66, 0.96) after adjusting for individual-level confounders. Approximately 11% of the total variance for insurance coverage was attributable to the state level; however, only 18% of state-level variability was explained by structural stigma. Adding Medicaid expansion attenuated the structural stigma-insurance association and explained 22% of state-level variation in health insurance. For the remaining outcomes (usual source of care, routine medical check-up, and cost-related barriers), we found neither meaningful associations nor considerable between-state variability.Our findings support the importance of Medicaid expansion and transgender-inclusive antidiscrimination protections to enhance health care insurance coverage. From a measurement perspective, however, additional research is needed to develop and validate measures of transgender-specific structural stigma to guide future policy interventions.

    View details for DOI 10.1177/13558196221123413

    View details for Web of Science ID 000847842100001

    View details for PubMedID 36040166

  • Sexual Behaviors Associated with HIV Transmission Among Transgender and Gender Diverse Young Adults: The Intersectional Role of Racism and Transphobia AIDS AND BEHAVIOR Lett, E., Asabor, E., Tran, N., Dowshen, N., Aysola, J., Gordon, A. R., Agenor, M. 2022


    HIV prevalence and engagement in sexual behaviors associated with HIV transmission are high among transgender people of color. Per intersectionality, this disproportionate burden may be related to both interpersonal and structural racism and transphobia. The goal of this study was to estimate the association between interpersonal and structural discrimination and sexual behaviors among transgender and gender diverse (TGD) U.S. young adults. We used logit models with robust standard errors to estimate the individual and combined association between interpersonal and structural racism and transphobia and sexual behaviors in a national online sample of TGD young adults of color (TYAOC) aged 18-30 years (N = 228). Racism was measured at the interpersonal and structural level using the Everyday Discrimination Scale and State Racism Index, respectively. Transphobia was measured at the interpersonal and structural level using the Gender Minority Stress Scale and the Gender Identity Tally, respectively. We found that interpersonal racism was associated with transactional sex, and interpersonal transphobia was associated with alcohol/drug consumption prior to sex and transactional sex among TYAOC. We also found evidence of a strong joint association of interpersonal and structural racism and transphobia with alcohol/drug consumption prior to sex (OR 3.85, 95% CI 2.12, 7.01) and transactional sex (OR 3.54, 95% CI 0.99, 12.59) among TYAOC. Racism and transphobia have a compounding impact on sexual behaviors among TYAOC. Targeted interventions that reduce discrimination at both the interpersonal and structural level may help reduce the HIV burden in this marginalized population.

    View details for DOI 10.1007/s10461-022-03701-w

    View details for Web of Science ID 000805892000002

    View details for PubMedID 35661016

  • Limited Risk Compensation Among Women Who Inject Drugs: Results From the Project Sexual Health Equity Preexposure Prophylaxis Demonstration Study in Philadelphia SEXUALLY TRANSMITTED DISEASES Tran, N. K., van der Pol, B., Shrestha, R., Bazzi, A. R., Bellamy, S. L., Sherman, S. G., Roth, A. M. 2022; 49 (5): E64-E66


    The impact of preexposure prophylaxis uptake on sexual and injection-related behaviors among women who inject drugs is poorly understood. Over 24 weeks, preexposure prophylaxis uptake among women who inject drugs was associated with increased sharing of injection equipment but not syringes and no changes in condomless sex, providing limited evidence of risk compensation in this vulnerable population.

    View details for DOI 10.1097/OLQ.0000000000001577

    View details for Web of Science ID 000783600600001

    View details for PubMedID 34694276

    View details for PubMedCentralID PMC9018480

  • Wearable biosensors have the potential to monitor physiological changes associated with opioid overdose among people who use drugs: A proof-of-concept study in a real-world setting DRUG AND ALCOHOL DEPENDENCE Roth, A. M., Tran, N. K., Cocchiaro, B., Mitchell, A. K., Schwartz, D. G., Hensel, D. J., Ataiants, J., Brenner, J., Yahav, I., Lankenau, S. E. 2021; 229: 109138


    Wearable biosensors have the potential to monitor physiological change associated with opioid overdose among people who use drugs.We enrolled 16 individuals who reported ≥ 4 daily opioid use events within the previous 30 day. Each was assigned a wearable biosensor that measured respiratory rate (RR) and actigraphy every 15 s for 5 days and also completed a daily interview assessing drug use. We describe the volume of RR data collected, how it varied by participant characteristics and drug use over time using repeated measures one-way ANOVA, episodes of acute respiratory depression (≤5 breaths/minute), and self-reported overdose experiences.We captured 1626.4 h of RR data, an average of 21.7 daily hours/participant over follow-up. Individuals with longer injection careers and those engaging in polydrug use captured significantly fewer total hours of respiratory data over follow-up compared to those with shorter injections careers (94.7 vs. 119.9 h, p = 0.04) and injecting fentanyl exclusively (98.7 vs. 119.5 h, p = 0.008), respectively. There were 385 drug use events reported over follow-up. There were no episodes of acute respiratory depression which corresponded with participant reports of overdose experiences.Our preliminary findings suggest that using a wearable biosensor to monitor physiological changes associated with opioid use was feasible. However, more sensitive biosensors that facilitate triangulation of multiple physiological data points and larger studies of longer duration are needed.

    View details for DOI 10.1016/j.drugalcdep.2021.109138

    View details for Web of Science ID 000730154200004

    View details for PubMedID 34781097

    View details for PubMedCentralID PMC8672322

  • Practical data considerations for the modern epidemiology student. Global epidemiology Tran, N. K., Lash, T. L., Goldstein, N. D. 2021; 3


    As an inherent part of epidemiologic research, practical decisions made during data collection and analysis have the potential to impact the measurement of disease occurrence as well as statistical and causal inference from the results. However, the computational skills needed to collect, manipulate, and evaluate data have not always been a focus of educational programs, and the increasing interest in "data science" suggest that data literacy has become paramount to ensure valid estimation. In this article, we first motivate such practical concerns for the modern epidemiology student, particularly as it relates to challenges in causal inference; second, we discuss how such concerns may be manifested in typical epidemiological analyses and identify the potential for bias; third, we present a case study that exemplifies the entire process; and finally, we draw attention to resources that can help epidemiology students connect the theoretical underpinning of the science to the practical considerations as described herein.

    View details for DOI 10.1016/j.gloepi.2021.100066

    View details for PubMedID 35844206

    View details for PubMedCentralID PMC9286486

  • Countering the rise of syphilis: A role for doxycycline post-exposure prophylaxis? INTERNATIONAL JOURNAL OF STD & AIDS Tran, N. K., Goldstein, N. D., Welles, S. L. 2022; 33 (1): 18-30


    Doxycycline post-exposure prophylaxis (PEP) holds the potential to mitigate increasing rates of syphilis among sexual minority men (SMM) in the US yet has received limited attention. Since evaluation of this intervention in actual populations is not currently feasible, we used agent-based models (ABM) to assess the population-level impact of this strategy. We adapted ABM of HIV and HPV transmission, representing a population of 10,230 SMM in Philadelphia, Pennsylvania, US. Parameter inputs were derived from the literature, and ABM outputs during the pre-intervention period were calibrated to local surveillance data. Intervention scenarios varied doxycycline uptake by 20, 40, 60, 80 and 100%, while assuming continued condom use and syphilis screening and treatment. Under each intervention scenario, we incorporated treatment adherence at the following levels: 0, 20, 40, 60, 80 and 100%. Long-term population impact of prophylactic doxycycline was measured using the cumulative incidence over the 10-year period and the percentage of infections prevented attributable to doxycycline at year 10. An uptake scenario of 20% with an adherence level of 80% would reduce the cumulative incidence of infections by 10% over the next decade, translating to 57 fewer cases per 1000 SMM. At year 10, under the same uptake and adherence level, 22% of infections would be prevented due to doxycycline PEP in the instances where condoms were not used or failed. Findings suggest that doxycycline PEP will have a modest impact on syphilis incidence when assuming a reasonable level of uptake and adherence. Doxycycline PEP may be most appropriate as a secondary prevention measure to condoms and enhanced syphilis screening for reducing infections among SMM.

    View details for DOI 10.1177/09564624211042444

    View details for Web of Science ID 000703127500001

    View details for PubMedID 34565255

    View details for PubMedCentralID PMC8688295

  • Integrating HIV Preexposure Prophylaxis With Community-Based Syringe Services for Women Who Inject Drugs: Results From the Project SHE Demonstration Study JAIDS-JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES Roth, A. M., Tran, N. K., Felsher, M., Gadegbeku, A. B., Piecara, B., Fox, R., Krakower, D. S., Bellamy, S. L., Amico, K., Benitez, J. A., Van der Pol, B. 2021; 86 (3): E61-E70


    To guide future preexposure prophylaxis (PrEP) implementation for women who inject drugs (WWID), a population increasingly represented in new HIV cases in the United States, we present results from a demonstration project integrated within a syringe services program (SSP) in Philadelphia, PA.WWID ≥18 years were educated about and offered 24 weeks of daily PrEP. Participants completed surveys and clinical assessments at baseline and at weeks 1, 3, 12, and 24. We used descriptive statistics to estimate feasibility/acceptability, engagement in the care cascade, HIV/sexually transmitted diseases (STI) and pregnancy, issues of safety/tolerability, and preferences/satisfaction with PrEP services. Multivariable logistic regression with generalized estimating equations was used to identify factors associated with PrEP uptake and retention.We recruited 136 WWID. Of those, 95 were included in the final sample, and 63 accepted a PrEP prescription at week 1. Uptake was associated with greater baseline frequency of SSP access [adjusted odds ratio (aOR) = 1.85; 95% confidence interval (CI): 1.24 to 2.77], inconsistent condom use (aOR = 3.38; 95% CI: 1.07 to 10.7), and experiencing sexual assault (aOR = 5.89; 95% CI: 1.02, 33.9). Of these 95, 42 (44.2%) were retained at week 24. Retention was higher among women who reported more frequent baseline SSP access (aOR = 1.46; 95% CI: 1.04 to 2.24). Self-reported adherence was high but discordant with urine-based quantification of tenofovir. Baseline STI prevalence was 17.9%; there were 2 HIV seroconversions and 1 pregnancy. Safety/tolerability issues were uncommon, and acceptability/satisfaction was high.Integrating PrEP with SSP services is feasible and acceptable for WWID. This suggests that daily PrEP is a viable prevention tool for this vulnerable population.

    View details for DOI 10.1097/QAI.0000000000002558

    View details for Web of Science ID 000656643900002

    View details for PubMedID 33148998

    View details for PubMedCentralID PMC7878321

  • Intention to initiate and uptake of PrEP among women who injects drugs in a demonstration project: an application of the theory of planned behavior AIDS CARE-PSYCHOLOGICAL AND SOCIO-MEDICAL ASPECTS OF AIDS/HIV Tran, N. K., Felsher, M., Van der Pol, B., Bellamy, S. L., McKnight, J., Roth, A. M. 2021; 33 (6): 746-753


    Some women who inject drugs (WWID) would benefit from pre-exposure prophylaxis (PrEP), yet there are few studies of issues related to uptake in real-world settings. In this study, participants (n = 95) were offered PrEP and responded to items measuring PrEP-related attitudes, norms, and perceived behavioral control based on the Theory of Planned Behavior. We tested associations with intention to initiate PrEP and uptake. Most WWID (88%) intended to initiate PrEP and 78% accepted a prescription. Compared to WWID who did not express PrEP intentions, those who did were less concerned about attitudinal and perceived behavioral control constructs such as temporary (75% vs. 36%, p = 0.01) and long-term (63% vs. 27%, p = 0.05) side effects, negative interactions with their birth control (93% vs. 38%, p < 0.01), their ability to take a daily pill (80% vs. 36%, p < 0.01), and the cost of PrEP (87% vs. 36%, p < 0.01). WWID who went on to take PrEP had fewer concerns with subjective norms constructs such as talking to health care providers about sex (91% vs. 65%, p < 0.01) and drug use (88% vs. 55%, p < 0.01) compared to those who did not. Attitudes and perceived behavioral control influenced intention while subjective norms had a greater impact on actual uptake.

    View details for DOI 10.1080/09540121.2021.1874267

    View details for Web of Science ID 000610175600001

    View details for PubMedID 33486981

    View details for PubMedCentralID PMC8140983

  • The heterogeneous effect of marijuana decriminalization policy on arrest rates in Philadelphia, Pennsylvania, 2009-2018 DRUG AND ALCOHOL DEPENDENCE Tran, N. K., Goldstein, N. D., Purtle, J., Massey, P. M., Lankenau, S. E., Suder, J. S., Tabb, L. P. 2020; 212: 108058


    Marijuana decriminalization holds potential to reduce health inequities. However, limited attention has focused on assessing the impact of decriminalization policies across different populations. This study aims to determine the differential effect of a marijuana decriminalization policy change in Philadelphia, PA on marijuana arrests by demographic characteristics.Using a comparative interrupted time series design, we assessed whether the onset of marijuana decriminalization in Philadelphia County was associated with reduction in arrests rates from 2009 to 2018 compared to Dauphin County. Stratified models were used to describe the differential impact of decriminalization across different demographic populations.Compared to Dauphin, the mean arrest rate for all marijuana-related crimes in Philadelphia declined by 19.9 per 100,000 residents (34.9% reduction), 17.1 per 100,000 residents (43.1% reduction) for possession, and 2.8 per 100,000 resident (15.9% reduction) for sales/manufacturing. Arrest rates also differed by demographic characteristics post-decriminalization. Notably, African Americans had a greater absolute/relative reduction in possession-based arrests than Whites. However, relative reductions for sales/manufacturing-based arrests was nearly 3 times lower for African Americans. Males had greater absolute/relative reduction for possession-based arrests, but lower relative reduction for sales/manufacturing-based arrests compared to females. There were no substantial absolute differences by age; however, youths (vs. adults) experienced higher relative reduction in arrest rates.Findings suggest an absolute/relative reduction for possession-based arrests post-decriminalization; however, relative disparities in sales/manufacturing-based arrests, specifically for African Americans, increased. More consideration towards the heterogeneous effect of marijuana decriminalization are needed given the unintended harmful effects of arrest on already vulnerable populations.

    View details for DOI 10.1016/j.drugalcdep.2020.108058

    View details for Web of Science ID 000540448800051

    View details for PubMedID 32442749

  • Prevalence and correlates of carrying naloxone among a community-based sample of opioid-using people who inject drugs INTERNATIONAL JOURNAL OF DRUG POLICY Reed, M., Wagner, K. D., Tran, N. K., Brady, K. A., Shinefeld, J., Roth, A. 2019; 73: 32-35


    Overdose prevention programs are effective at reducing opioid overdose deaths through training people who inject drugs (PWID) how to respond to witnessed overdoses and use naloxone. This report examines prevalence and correlates of carrying naloxone among a community-based sample of PWID.Using respondent driven sampling, PWID (n = 571) in Philadelphia, PA were recruited for the 2015 National HIV Behavioral Surveillance project. The impact of socio-demographics, social services, and law enforcement interaction on naloxone carrying were analyzed using multivariable logistic regression.Odds of carrying naloxone were higher among PWID who were: homeless (adjusted odds ratio [aOR] = 1.65, 95% confidence interval [CI]: 1.01, 2.83), reported a syringe exchange program as their primary source of syringes (aOR = 2.92, CI: 1.68, 5.09), and had been stopped by police ≥6 times (aOR = 2.16, CI: 1.12, 4.16) or arrested (aOR = 1.84, CI: 1.02, 3.30) in the past year.Syringe exchange access was associated with naloxone carrying and is likely a primary source for naloxone and overdose reversal training for PWID. Homelessness and law enforcement encounters are known barriers to harm reducing behaviors; however, both were positively associated with carrying naloxone in this sample. Larger studies are needed to explore these relationships in greater depth.

    View details for DOI 10.1016/j.drugpo.2019.07.010

    View details for Web of Science ID 000504514600005

    View details for PubMedID 31336291

  • Heterosexual Men Anticipate Risk Compensatory Behaviors With Future Preexposure Prophylaxis Initiation: Findings From an Exploratory Cross-Sectional Study SEXUALLY TRANSMITTED DISEASES Roth, A. M., Nguyen Tran, Felsher, M., Szep, Z., Krakower, D. 2019; 46 (10): E97-E100


    Among 146 urban heterosexuals screening negative for human immunodeficiency virus, one third anticipated increased sexual risk taking with human immunodeficiency virus preexposure prophylaxis. Men (vs. women) and black (vs. white) participants had increased odds for anticipating decreased condom use. Men and persons reporting transactional sex expected to increase sexual partnerships. Risk compensation could affect reproductive health and disease control.

    View details for DOI 10.1097/OLQ.0000000000001012

    View details for Web of Science ID 000505802900002

    View details for PubMedID 31033806


    View details for DOI 10.1093/aje/kwz141

    View details for Web of Science ID 000492998200021

    View details for PubMedID 31172181

  • Factors Associated with Awareness of Pre-exposure Prophylaxis for HIV Among Persons Who Inject Drugs in Philadelphia: National HIV Behavioral Surveillance, 2015 AIDS AND BEHAVIOR Roth, A., Nguyen Tran, Piecara, B., Welles, S., Shinefeld, J., Brady, K. 2019; 23 (7): 1833-1840


    Persons who inject drugs (PWID) continue to experience disproportionate HIV burden. Though studies demonstrate PWID find pre-exposure prophylaxis (PrEP) acceptable, awareness and uptake remains low. Data from the 2015 PWID cycle of the National HIV Behavioral Surveillance (n = 612) in Philadelphia, Pennsylvania (USA) were analyzed to evaluate how socio-demographics and behavioral factors impact PrEP awareness. Only 12.4% of PWID surveyed were PrEP-aware and 2.6% reported receiving a prescription. Factors associated with PrEP awareness included having at least some college education (aOR 2.13, 95% CI 1.03, 4.43), sharing paraphernalia (aOR 2.37, 95% CI 1.23, 4.56), obtaining syringes/needles primarily from a syringe exchange program (aOR 2.28, 95% CI 1.35, 3.87), STI testing (aOR 1.71, 95% CI 1.01, 2.89) and drug treatment (aOR 2.81, 95% CI 1.62, 4.87). Accessing prevention and health services increased the odds of being PrEP-aware; however, awareness was low overall. Additional promotion efforts are warranted.

    View details for DOI 10.1007/s10461-018-2293-0

    View details for Web of Science ID 000471709800015

    View details for PubMedID 30267367

  • Modeling HPV vaccination scale-up among urban young men who have sex with men in the context of HIV VACCINE Goldstein, N. D., LeVasseur, M. T., Tran, N. K., Purtle, J., Welles, S. L., Eppes, S. C. 2019; 37 (29): 3883-3891


    Young men who have sex with men (YMSM) are at high risk to contract human papillomavirus (HPV). While an effective vaccination exists, its use among YMSM is markedly lower compared to non-MSM and women. This study compares scaling up HPV vaccination in conjunction with other prevention strategies.An agent-based model of urban YMSM (≤26 years of age) reflective of the demography of Philadelphia, PA, simulated for up to ten years of follow-up to examine anal and oral transmission of the HPV genotypes covered in the nonavalent (9v) vaccine: 6, 11, 16, 18, 31, 33, 45, 52, 58. Starting HPV prevalences ranged from a high of 18% (type 6) to a low of 6% (type 31); overall 65% of individuals carried any HPV genotype. Simulated levels of vaccination were ranged from 0% to 13% (present-day level), 25%, 50%, 80% (Healthy People 2020 target), and 100% in conjunction with condom use and HIV seroadaptive practices. The primary outcome was the relative reduction in HPV infection.Compared to present-day vaccination levels (13%), scaling-up vaccination led to expected declines in 10-year post-simulation HPV prevalence. Anal HPV (any 9v types) declined by 9%, 27%, 46%, and 58% at vaccination levels of 25%, 50%, 80%, and 100%, respectively. Similarly, oral HPV (any 9v types) declined by 11%, 33%, 57%, and 71% across the same levels of vaccine uptake. Comparing the prevention strategies, condoms blocked the greatest number of anal transmissions when vaccination was at or below present-day levels. For oral transmission, vaccination was superior to condom use at all levels of coverage.Public health HPV preventions strategies should continue to emphasize the complementary roles of condoms and vaccination, especially for preventing oral infection. Improving vaccination coverage will ultimately have the greatest impact on reducing HPV infection among YMSM.

    View details for DOI 10.1016/j.vaccine.2019.05.047

    View details for Web of Science ID 000472984900019

    View details for PubMedID 31155416

  • Four Decades of Epidemiologic Science on HIV Infection and Disease, and Its Impact on Public Health Practice and Policy for Sexual and Gender Minority Persons. Delaware journal of public health Tran, N. K., Welles, S. L. 2019; 5 (2): 64-71


    Even at the cusp of the second decade of the new millennia, HIV continues to be a significant public health challenge for sexual and gender minorities (SGM). Men who have sex with men and transgender women, in particular, continue to report higher rates of HIV incidence compared to their heterosexual counterparts, while facing significant barriers to comprehensive sexual healthcare. In Delaware, HIV infection impacts a substantial number of individuals with approximately 14.5 incident cases per 100,000. This ranks Delaware as the 14th highest for HIV incidence among U.S. states. However, the largest healthcare provider in Delaware, Christiana Care Health System, has created many health initiatives to support the health needs of SGM and those living with HIV. The current sustained rate of HIV infection indicates the need for enhanced epidemiologic work to identify HIV cases in subgroups of diverse sexuality and gender identity, collaboration within and across research institution and community organizations, as well as engagement in creative solutions that target the multiple levels of factors contributing to HIV incidence. In addition, it is imperative that local agencies and health organizations continue to support these communities of SGM individuals during the current sociopolitical climate of the national U.S. government.

    View details for DOI 10.32481/djph.2019.05.011

    View details for PubMedID 34467031

    View details for PubMedCentralID PMC8396754

  • Pre-Exposure Prophylaxis (PrEP) Awareness Is Low Among Heterosexual People of Color Who Might Benefit From PrEP in Philadelphia JOURNAL OF PRIMARY CARE AND COMMUNITY HEALTH Roth, A. M., Tran, N. K., Piecara, B. L., Shinefeld, J., Brady, K. A. 2019; 10: 2150132719847383


    We assessed awareness of pre-exposure prophylaxis (PrEP) among HIV-negative Black and Latinx persons living in the Philadelphia Metropolitan Statistical Area.Using chi-square and Wilcoxon rank-sum tests, we analyzed data from the 2016 heterosexual cycle of the National HIV Behavioral Surveillance system to assess how sociodemographic factors, health care utilization, and risk behaviors affected PrEP awareness.Participants (n = 472) were predominately Black, non-Hispanic (88.1%) with a median age of 41.5 years. Most participants reported having a usual source of medical care (92.1%) and seeing a medical provider within 12 months (87.0%). However, PrEP awareness was low in this sample (4.9%) and was lower among those who had a medical visit compared with those who had not ( P < .01).Current Centers for Disease Control and Prevention clinical guidelines suggest that providers counsel high-risk patients about PrEP. Our data suggest that this is not happening with people of color in Philadelphia. Interventions targeting medical providers working with HIV-risk people of color may be appropriate.

    View details for DOI 10.1177/2150132719847383

    View details for Web of Science ID 000468917300001

    View details for PubMedID 31079518

    View details for PubMedCentralID PMC6537238

  • Potential Relationship Between HIV Criminalization and Structural Stigma Related to Sexual Orientation in the United States JAIDS-JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES Tran, N. K., Hatzenbuehler, M. L., Goldstein, N. D. 2019; 80 (5): E106-E108

    View details for DOI 10.1097/QAI.0000000000001961

    View details for Web of Science ID 000480767800001

    View details for PubMedID 30664076

  • Drawing from the Theory of Planned Behaviour to examine pre-exposure prophylaxis uptake intentions among heterosexuals in high HIV prevalence neighbourhoods in Philadelphia, Pennsylvania, USA: an observational study SEXUAL HEALTH Roth, A., Felsher, M., Nguyen Tran, Bellamy, S., Martinez-Donate, A., Krakower, D., Szep, Z. 2019; 16 (3): 218-224


    Background Research surrounding attitudes and intentions concerning pre-exposure prophylaxis (PrEP) among at-risk heterosexuals, women and ethnic and racial minorities is needed to inform programs to scale this effective HIV prevention intervention among these populations.The study sample includes 192 HIV-negative heterosexuals recruited from HIV testing sites operating in high HIV prevalence neighbourhoods in a mid-Atlantic city. Participants received brief educational sessions on PrEP and completed a self-administered survey assessing sociodemographic factors, HIV risk behaviours and theoretical determinants of PrEP uptake, based on the Theory of Planned Behaviour.Participants were majority persons of colour (86%), with a median age of 43 years. Compared with Whites, a higher percentage of Black and Brown persons had more than five sex partners (75.0%), used condoms inconsistently (85.6%) and engaged in transactional sex (84.4%). Most expressed positive PrEP attitudes and indicated intention to adopt PrEP, especially if recommended by their doctor. In a multivariable model, willingness to take PrEP if suggested by a healthcare provider (aOR: 4.17; 95% CI: 1.42-12.24) and willingness to take PrEP even if it caused side-effects (aOR: 1.98; 95% CI: 1.01-3.90) were both associated with greater PrEP adoption intentions.A diverse at-risk population was identified through community-based HIV testing. Low perceived HIV risk, as well as PrEP-related attitudes, subjective norms and perceived behavioural control were associated with PrEP use intentions. These factors are potential targets for interventions to increase PrEP adoption among diverse heterosexual samples.

    View details for DOI 10.1071/SH18081

    View details for Web of Science ID 000474861300003

    View details for PubMedID 31079596

  • Examining unmet needs: a cross-sectional study exploring knowledge, attitudes and sexually transmitted infection screening preferences among persons who inject drugs in Camden, New Jersey SEXUALLY TRANSMITTED INFECTIONS Roth, A., Nguyen Khai Tran, Chavis, M., Van Der Pol, B. 2018; 94 (8): 598-603


    To inform the development of targeted sexually transmitted infection (STI) control programmes for persons who inject drugs (PWID).We recruited 116 PWID (aged ≥ 18 years) from a community-based syringe exchange programme (SEP) and assessed their STI knowledge and screening preferences via technology assisted self-interview. We estimated prevalence of STI transmission knowledge, attitudes and screening preferences as well as the association between reported sexual behaviours (past 6 months) and willingness to self-collect specimens.Participants were white (77%), female (51%) and heterosexual (77%). STI knowledge regarding transmission and testing was high among the sample. More than 70% of participants were aware extragenital infections were possible and were least likely to know urine tests do not detect rectal infections (40.9%). Site-specific specimen collection was highly reflective of reported sexual behaviour. PWID who reported receptive sex (36% vs 5%, p<0.01) and insertive anal sex (31% vs 6%, p=0.01) were more likely to collect rectal specimens than those who did not. A similar trend was seen for oral sex performance on men and self-collection of oropharyngeal swabs (15% vs 3%, p=0.04). In addition, participants preferred collecting their own sample to having a clinician collect it for them (69% vs 31%, p<0.01) and testing at the SEP compared with a STI clinic (86% vs 14%, p<0.01).Our findings suggest site-specific specimen collection may be a proxy for risk behaviour engagement in this fairly knowledgeable high-risk population. To increase case finding, STI control programmes should educate patients about site-specific screening and pair outreach with the infrastructure provided by SEPs, in settings where these programmes exist.

    View details for DOI 10.1136/sextrans-2017-053498

    View details for Web of Science ID 000452793400016

    View details for PubMedID 29960982



    The Health Belief Model has been useful for studying uptake of HIV prevention behaviors and has had limited application to understanding utilization of pre-exposure prophylaxis (PrEP), a biomedical strategy to reduce HIV acquisition. We recruited 90 persons undergoing HIV screening and educated them about PrEP. We followed up with 35 participants approximately 3 weeks later and quantitatively assessed PrEP uptake. No participant had initiated PrEP. We conducted in-depth interviews with 15 participants to explore situational factors impacting this decision. In this paper we provide an overview of PrEP-related engagement using qualitative data to contextualize (in)action. While participants perceived PrEP as beneficial, perceived benefits did not outweigh real- and perceived barriers, such as financial and time-related constraints. In order to promote PrEP uptake, cues to action that increase the benefits of PrEP during seasons of risk, and interventions that reduce real and perceived barriers are needed.

    View details for DOI 10.1521/aeap.2018.30.5.369

    View details for Web of Science ID 000447642100002

    View details for PubMedID 30332306

    View details for PubMedCentralID PMC8558876

  • Bias Adjustment Techniques Are Underutilized in HIV Sexual Risk Estimation: A Systematic Review INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH Tran, N. K., Goldstein, N. D., Welles, S. L. 2018; 15 (8)


    Background: Valid measurement of determinants of HIV infection among men who have sex with men (MSM) is critical for intervention planning and resource allocation. However, sexual minority research concerning HIV risk often relies on proxy exposures of sexual behaviors such as sexual orientation and partner gender. Inferring high risk sexual behaviors (i.e., condomless anal intercourse) from these proxies inaccurately captures HIV risk, but few studies have attempted to correct for this bias. Methods: We performed a systematic review of methodological practices for estimating risk of HIV infection among MSM. Results: We identified 32 studies in which high risk sexual behavior was assessed: 82% (n = 26) measured and used sexual risk behaviors (e.g., condomless anal intercourse or sexual positioning) to assess risk of HIV infection; 9% (n = 3) used proxy measures; and 9% (n = 3) used both behavior and proxy variables. Various treatments of misclassification reported by investigators included the following: 82% (n = 26) discussed misclassification of sexual behavior as a potential limitation; however, among these studies, no attempts were made to correct misclassification; 12% (n = 4) did not report exposure misclassification, and 6% (n = 2) explicitly considered this information bias and conducted a Bayesian approach to correct for misclassification. Conclusions: Our systematic review indicates that a majority of studies engaging in collecting primary data have taken additional steps to acquire detailed information regarding sexual risk behaviors. However, reliance on population-based surveys may still lead to potentially biased estimates. Thus, bias analytic techniques are potential tools to control for any suspected biases.

    View details for DOI 10.3390/ijerph15081696

    View details for Web of Science ID 000443168200136

    View details for PubMedID 30096874

    View details for PubMedCentralID PMC6121670