Glenn-Milo Santos, PhD, MPH

Affiliated Faculty

I am Professor in the Department of Community Health Systems and the Division of Prevention Science at the University of California, San Francisco, and a Senior Research Scientist at the San Francisco Department of Public Health. I have been conducting research on the intersection between substance use (i.e., alcohol, methamphetamine, cocaine, and opioids), and HIV, and intervention research studies among key populations at risk for HIV (i.e., men who have sex with men [MSM], transgender individuals, and people who use drugs) for 15 years. My contributions to Science are summarized below:

1. A significant thread of my research has investigated the factors associated with HIV risk among key affected populations. I have published multiple articles that have demonstrated how a myriad of social, behavioral, and structural factors play a role in sustaining the HIV epidemic among men who have sex with men (MSM), transgender women, and people who use drugs. These publications describe how the co-occurrence of these factors may result in heightened risk for HIV and underscore the need for multi-level interventions that jointly address these “syndemic” conditions. Furthermore, I have published extensively on how stigma, discrimination, and criminalization impacts access to evidence-based interventions. Most recently, I also published one of the first global studies to document the disparate impact of COVID-19 on HIV prevention and treatment service accessibility among MSM who engage in sex work, were from immigrant backgrounds, were racial/ethnically minoritized, and who have lower socio-economic status in the journal AIDS and Behavior.

2. In addition to conducting epidemiologic studies on the determinants of HIV risk among key populations, I have actively engaged in the design and evaluation of interventions to address modifiable risk factors linked to HIV risk. In particular, I have conducted randomized-controlled, pharmacologic and behavioral intervention trials to reduce substance use and substance-associated sexual risk behaviors among key populations. I was the primary analyst in the first randomized, placebo-controlled trial that efficaciously reduced methamphetamine urine-positivity and methamphetamine-associated sexual risk behaviors in intention-to-treat analyses. Additionally, I was the lead author of the first article that have demonstrated the efficacy of Personalized Cognitive Counseling (PCC) in reducing alcohol and substance use among MSM—these findings has been included in the CDC’s Compendium of Evidence-Based Interventions and Best Practices for HIV Prevention. These studies are also unique because they have enrolled active-substance users who are not seeking substance use treatment and support the feasibility of conducting research based on harm-reduction principles.

3. I am also actively conducting research on the health outcomes among people living with HIV. In this capacity, I have examined outcomes along the HIV care continuum and evaluated predictors of linkage, retention and engagement in care, and virologic suppression. Additionally, I have published papers on the collateral benefits of ART initiation and the correlates of spontaneous HCV clearance using data from longitudinal cohort studies among people living with HIV. I was also involved in the seminal study that demonstrated the association between community viral load (i.e., a community's average level of HIV infectiousness) and newly diagnosed HIV infections. This paper, which has been cited 851 times, provided proof of concept data for the Treatment as Prevention (“TasP”) approach.

4. As a translational research scientist and epidemiologist, I have also endeavored to synthesize research findings across multiple studies. I conducted the first systematic review and meta-analysis on the efficacy of behavioral interventions on amphetamine-group substances, published on The Lancet. As the primary analyst in this paper, I created the fixed and random-effects models for the meta-analyses conducted in the review, which demonstrated that high-intensity behavioral interventions are efficacious in reducing methamphetamine in pooled analyses. I was also the lead author in a narrative review synthesizing the literature on non-injection substance use interventions among MSM. Most recently, I was the senior author in a narrative review on novel intervention to prevent HIV and Hepatitis C among people who inject drugs. Both narrative reviews provided an up-to-date account of the state of prevention science and highlighted the most promising interventions for substance users. Additionally, I published a meta-analyses on the psychometric properties of measures of substance use with collaborators from the HIV Prevention Trials Network.
B.A., - Biology, Carleton College
Ph.D., - Department of Epidemiology and Biostatistics, University of California San Francisco
- Diversity, Equity, and Inclusion Champion Training, University of California San Francisco
M.P.H., - Division of Epidemiology, School of Public Health, University of California, Berkeley
Honors and Awards
  • National Institutes of Health Director’s Early Independence Award, National Institutes of Health, Office of the Director, 2014
  • University of California President’s Dissertation-Year Fellowship Program Award, University of California Office of the President, 2013
  • Graduate Research Mentorship Fellowship, Graduate Division, University of California, San Francisco, 2012
  • National Institute on Drug Abuse Dissertation Research Award, National Institutes of Health, 2012
  • Young Innovator in HIV Research, 2011 National HIV Prevention Conference, Centers For Disease Control and Prevention, 2011
  • Gold Star Scientific Merit Award, 6th IAS Conference On HIV Pathogenesis, Treatment and Prevention, 2011
  • Youth Health Advisor, San Francisco Health Commission, 2005
  • Freeman Foundation Research Fellowship, Carleton College, 2003
  1. Santos GM, Hong C, Wilson N, Nutor JJ, Harris O, Garner A, Holloway I, Ayala G, Howell S. Persistent disparities in COVID-19-associated impacts on HIV prevention and care among a global sample of sexual and gender minority individuals. 2022. PMID: 35435149

  2. Suen LW, McMahan VM, Rowe C, Bhardwaj S, Knight K, Kushel MB, Santos GM, Coffin P. Factors Associated with Pain Treatment Satisfaction Among Patients with Chronic Non-Cancer Pain and Substance Use. 2021. PMID: 34772764

  3. Santos GM, Ikeda J, Coffin P, Walker JE, Matheson T, McLaughlin M, Jain J, Vittinghoff E, Batki SL. Pilot study of extended-release lorcaserin for cocaine use disorder among men who have sex with men: A double-blind, placebo-controlled randomized trial. 2021. PMID: 34265007

  4. Rao A, Rucinski K, Jarrett BA, Ackerman B, Wallach S, Marcus J, Adamson T, Garner A, Santos GM, Beyrer C, Howell S, Baral S. Perceived Interruptions to HIV Prevention and Treatment Services Associated With COVID-19 for Gay, Bisexual, and Other Men Who Have Sex With Men in 20 Countries. 2021. PMID: 33443963

  5. Beliveau CM, McMahan VM, Arenander J, Angst MS, Kushel M, Torres A, Santos GM, Coffin PO. Stimulant use for self-management of pain among safety-net patients with chronic non-cancer pain. 2021. PMID: 33798030

  6. Haq N, McMahan VM, Torres A, Santos GM, Knight K, Kushel M, Coffin PO. Race, pain, and opioids among patients with chronic pain in a safety-net health system. 2021. PMID: 33810908

  7. Santos GM, Miller D, Jain J, Gyamerah A, Wilson E, Mcfarland W, Raymond HF. Prevalence and Correlates of Methamphetamine Use Among Older Men Who Have Sex with Men in San Francisco 2021. PMID:

  8. Santos GM, Ackerman B, Rao A, Wallach S, Ayala G, Lamontage E, Garner A, Holloway IW, Arreola S, Silenzio V, Strömdahl S, Yu L, Strong C, Adamson T, Yakusik A, Doan TT, Huang P, Cerasuolo D, Bishop A, Noori T, Pharris A, Aung M, Dara M, Chung SY, Hanley M, Baral S, Beyrer C, Howell S. Economic, Mental Health, HIV Prevention and HIV Treatment Impacts of COVID-19 and the COVID-19 Response on a Global Sample of Cisgender Gay Men and Other Men Who Have Sex with Men. 2021. PMID: 32654021

  9. Rowe CL, Santos GM, Kornbluh W, Bhardwaj S, Faul M, Coffin PO. Using ICD-10-CM codes to detect illicit substance use: A comparison with retrospective self-report. 2021. PMID: 33621806

  10. Zepf R, Greene M, Hessol NA, Johnson MO, Santos GM, John MD, Dawson-Rose C. Syndemic conditions and medication adherence in older men living with HIV who have sex with men. 2020. PMID: 32468831

  11. Santos GM, Strathdee SA, El-Bassel N, Patel P, Subramanian D, Horyniak D, Cook RR, McCullagh C, Marotta P, Choksi F, Kang B, Allen I, Shoptaw S. Psychometric properties of measures of substance use: a systematic review and meta-analysis of reliability, validity and diagnostic test accuracy. 2020. PMID: 32380951

  12. Coffin PO, Rowe C, Oman N, Sinchek K, Santos GM, Faul M, Bagnulo R, Mohamed D, Vittinghoff E. Illicit opioid use following changes in opioids prescribed for chronic non-cancer pain. 2020. PMID: 32365132

  13. McFarland W, Lin J, Santos GM, Arayasirikul S, Raymond HF, Wilson E. Low PrEP Awareness and Use Among People Who Inject Drugs, San Francisco, 2018. 2019. PMID: 31563984

  14. Hsiang E, Offer C, Prescott M, Rodriguez A, Behar E, Matheson T, Santa Maria D, Santos GM. Bridging the Digital Divide Among Racial and Ethnic Minority Men Who Have Sex With Men to Reduce Substance Use and HIV Risk: Mixed Methods Feasibility Study. 2020. PMID: 32347807

  15. Coffin PO, Santos GM, Hern J, Vittinghoff E, Walker JE, Matheson T, Santos D, Colfax G, Batki SL. Effects of Mirtazapine for Methamphetamine Use Disorder Among Cisgender Men and Transgender Women Who Have Sex With Men: A Placebo-Controlled Randomized Clinical Trial. 2020. PMID: 31825466

  16. Coffin PO, Santos GM, Behar E, Hern J, Walker J, Matheson T, Kinnard EN, Silvis J, Vittinghoff E, Fox R, Page K. Randomized feasibility trial of directly observed versus unobserved hepatitis C treatment with ledipasvir-sofosbuvir among people who inject drugs. 2019. PMID: 31158245

  17. Behar E, Chang JS, Countess K, Matheson T, Santos GM, Coffin P. Perceived Causes of Personal versus Witnessed Overdoses among People who Inject Opioids. 2019. PMID: 31070106

  18. Baguso GN, Turner CM, Santos GM, Raymond HF, Dawson-Rose C, Lin J, Wilson EC. Successes and final challenges along the HIV care continuum with transwomen in San Francisco. 2019. PMID: 31037858

  19. Hsiang E, Jennings D, Matheson T, Hern J, Euren J, Santos GM. Acceptability of pharmacotherapy for hazardous alcohol use among men who have sex with men: Findings from a qualitative study. 2018. PMID: 30258972

  20. Santos GM, Rowe C, Hern J, Walker JE, Ali A, Ornelaz M, Prescott M, Coffin P, McFarland W, Raymond HF. Prevalence and correlates of hazardous alcohol consumption and binge drinking among men who have sex with men (MSM) in San Francisco. 2018. PMID: 30118495

  21. Rowe C, Wheeler E, Vittinghoff E, Santos GM, Behar E, Coffin PO. Quantity fluctuations of illicitly used opioids and overdose risk. 2018. PMID: 29807248

  22. Turner C, Chandrakumar D, Rowe C, Santos GM, Riley ED, Coffin PO. Cross-sectional cause of death comparisons for stimulant and opioid mortality in San Francisco, 2005-2015. 2018. PMID: 29486419

  23. Rowe C, Vittinghoff E, Colfax G, Coffin PO, Santos GM. Correlates of Validity of Self-Reported Methamphetamine Use among a Sample of Dependent Adults. 2018. PMID: 29461134

  24. Santa Maria D, Padhye N, Yang Y, Gallardo K, Santos GM, Jung J, Businelle M. Drug use patterns and predictors among homeless youth: Results of an ecological momentary assessment. 2017. PMID: 29286835

  25. Smith-Bernardin S, Rowe C, Behar E, Geier M, Washington S, Santos GM, Euren J, Martin J, Gleghorn A, Coffin PO. Low-threshold extended-release naltrexone for high utilizers of public services with severe alcohol use disorder: A pilot study. 2017. PMID: 29150316

  26. Coffin PO, Santos GM, Matheson T, Behar E, Rowe C, Rubin T, Silvis J, Vittinghoff E. Behavioral intervention to reduce opioid overdose among high-risk persons with opioid use disorder: A pilot randomized controlled trial. 2017. PMID: 29049282

  27. Coffin PO, Santos GM, Hern J, Vittinghoff E, Santos D, Matheson T, Colfax G, Batki SL. Extended-release naltrexone for methamphetamine dependence among men who have sex with men: a randomized placebo-controlled trial. 2017. PMID: 28734107

  28. Guigayoma J, Chen YH, Snowden JM, Santos GM, Hecht J, Raymond HF. Self-Perceived Viral Load and Sexual Risk Behavior Among Known HIV-Positive MSM in San Francisco, 2014. 2017. PMID: 28604432

  29. Rowe C, Vittinghoff E, Santos GM, Behar E, Turner C, Coffin PO. Performance Measures of Diagnostic Codes for Detecting Opioid Overdose in the Emergency Department. 2017. PMID: 27763703

  30. John Walker, Deirdre Santos, Chris Rowe, Glenn-Milo Santos, Sue Jung, Phillip Coffin. A novel approach to naltrexone injections may reduce complications and increase adherence. 2017. PMID:

  31. Behar E, Rowe C, Santos GM, Santos N, Coffin PO. Academic Detailing Pilot for Naloxone Prescribing Among Primary Care Providers in San Francisco. 2017. PMID: 28218937

  32. Glenn-Milo Santos, Phillip Coffin, D. Santos, S. Huffaker, T. Matheson, Jason Euren, Anna DeMartini, Christopher Rowe, Judith Hahn, David Vlahov, Eric Vittinghoff, Steven L. Batki. Feasibility, acceptability, tolerability of targeted naltrexone for non-dependent methamphetamine – Using and binge-drinking men who have sex with men. 2017. PMID:

  33. Jennifer P. Jain, Glenn-Milo Santos, Susan Scheer, Steve Gibson, Pierre-Cedric Crouch, Robert Kohn, Walter Chang, Adam Carrico. Rates and correlates of syphilis reinfection among men who have sex with men in San Francisco. 2017. PMID:

  34. Turner CM, Coffin P, Santos D, Huffaker S, Matheson T, Euren J, DeMartini A, Rowe C, Batki S, Santos GM. Race/ethnicity, education, and age are associated with engagement in ecological momentary assessment text messaging among substance-using MSM in San Francisco. 2017. PMID: 28237053

  35. Rowe C, Santos GM, Raymond HF, Coffin PO. Social mixing and correlates of injection frequency among opioid use partnerships. 2017. PMID: 28113118

  36. Jain J, Santos GM, Scheer S, Gibson S, Crouch PC, Kohn R, Chang W, Carrico AW. Rates and Correlates of Syphilis Reinfection in Men Who Have Sex with Men. 2016. PMID: 27991843

  37. Behar E, Rowe C, Santos GM, Coffa D, Turner C, Santos NC, Coffin PO. Acceptability of Naloxone Co-Prescription Among Primary Care Providers Treating Patients on Long-Term Opioid Therapy for Pain. 2016. PMID: 27815762

  38. Behar E, Rowe C, Santos GM, Murphy S, Coffin PO. Primary Care Patient Experience with Naloxone Prescription. 2016. PMID: 27621159

  39. Scheim AI, Santos GM, Arreola S, Makofane K, Do TD, Hebert P, Thomann M, Ayala G. Inequities in access to HIV prevention services for transgender men: results of a global survey of men who have sex with men. 2016. PMID: 27431466

  40. Coffin PO, Behar E, Rowe C, Santos GM, Coffa D, Bald M, Vittinghoff E. Nonrandomized Intervention Study of Naloxone Coprescription for Primary Care Patients Receiving Long-Term Opioid Therapy for Pain. 2016. PMID: 27366987

  41. Rowe C, Liou T, Vittinghoff E, Coffin PO, Santos GM. Binge drinking concurrent with anal intercourse and condom use among men who have sex with men. 2016. PMID: 27241085

  42. Santos GM, Coffin P, Santos D, Huffaker S, Matheson T, Euren J, DeMartini A, Rowe C, Hahn JA, Vlahov D, Vittinghoff E, Batki SL. Feasibility, Acceptability, and Tolerability of Targeted Naltrexone for Nondependent Methamphetamine-Using and Binge-Drinking Men Who Have Sex with Men. 2016. PMID: 26674372

  43. Rowe C, Matheson T, Das M, DeMicco E, Herbst JH, Coffin PO, Santos GM. Correlates of recent HIV testing among substance-using men who have sex with men. 2016. PMID: 27000299

  44. Rowe C, Santos GM, Vittinghoff E, Wheeler E, Davidson P, Coffin PO. Neighborhood-Level and Spatial Characteristics Associated with Lay Naloxone Reversal Events and Opioid Overdose Deaths. 2016. PMID: 26800987

  45. Rowe C, Santos GM, Behar E, Coffin PO. Correlates of overdose risk perception among illicit opioid users. 2015. PMID: 26754425

  46. Cohen JK, Santos GM, Moss NJ, Coffin PO, Block N, Klausner JD. Regular clinic attendance in two large San Francisco HIV primary care settings. 2015. PMID: 26654093

  47. Phillip O. Coffin, Christopher Rowe, Glenn-Milo Santos, Eric Vittinghoff, Eliza Wheeler. Characteristics and predictors of naloxone utilization in a community-based overdose prevention program. 2015. PMID:

  48. de Haan G, Santos GM, Arayasirikul S, Raymond HF. Non-Prescribed Hormone Use and Barriers to Care for Transgender Women in San Francisco. 2015. PMID: 26788772

  49. Visconti AJ, Santos GM, Lemos NP, Burke C, Coffin PO. Opioid Overdose Deaths in the City and County of San Francisco: Prevalence, Distribution, and Disparities. 2015. PMID: 26077643

  50. Rowe C, Santos GM, Vittinghoff E, Wheeler E, Davidson P, Coffin PO. Predictors of participant engagement and naloxone utilization in a community-based naloxone distribution program. 2015. PMID: 25917125

  51. Asiimwe SB, Fatch R, Emenyonu NI, Muyindike WR, Kekibiina A, Santos GM, Greenfield TK, Hahn JA. Comparison of Traditional and Novel Self-Report Measures to an Alcohol Biomarker for Quantifying Alcohol Consumption Among HIV-Infected Adults in Sub-Saharan Africa. 2015. PMID: 26148140

  52. Coffin PO, Rowe C, Santos GM. Novel interventions to prevent HIV and HCV among persons who inject drugs. 2015. PMID: 25589380

  53. Scheim AI, Arreola S, Do T, Makofane K, Santos GM, Thomann M, Wilson PA, Ayala G. Potential for conceptual bias in studies of racial disparities in HIV infection. 2015. PMID: 25296101

  54. Arreola S, Santos GM, Beck J, Sundararaj M, Wilson PA, Hebert P, Makofane K, Do TD, Ayala G. Sexual stigma, criminalization, investment, and access to HIV services among men who have sex with men worldwide. 2015. PMID: 25086670

  55. Behar E, Santos GM, Wheeler E, Rowe C, Coffin PO. Brief overdose education is sufficient for naloxone distribution to opioid users. 2014. PMID: 25595053

  56. Ayala G, Makofane K, Santos GM, Arreola S, Hebert P, Thomann M, Wilson P, Beck J, Do TD. HIV Treatment Cascades that Leak: Correlates of Drop-off from the HIV Care Continuum among Men who have Sex with Men Worldwide 2014. PMID:

  57. Coffin PO, Santos GM, Colfax G, Das M, Matheson T, DeMicco E, Dilley J, Vittinghoff E, Raiford JL, Carry M, Herbst JH. Adapted personalized cognitive counseling for episodic substance-using men who have sex with men: a randomized controlled trial. 2014. PMID: 24510401

  58. Phillip O. Coffin, G. Santos, M. Das, D. Santos, T. Matheson, J. Gasper, E. Vittinghoff, G. Colfax. Aripiprazole for the treatment of methamphetamine dependence: A randomized, double-blind, placebo-controlled trial. 2014. PMID:

  59. Dennis J. Dacarett-Galeano, G.M. Santos, D. Santos, M. Das, Phillip O. Coffin. Spatial and neighborhood-level correlates of retention in pharmacologic efficacy trials. 2014. PMID:

  60. Knight KR, Das M, DeMicco E, Raiford JL, Matheson T, Shook A, Antunez E, Santos GM, Dadasovich R, Dilley JW, Colfax GN, Herbst JH. A roadmap for adapting an evidence-based HIV prevention intervention: personal cognitive counseling (PCC) for episodic substance-using men who have sex with men. 2014. PMID: 23412947

  61. Asher AK, Santos GM, Evans J, Dokubo EK, Lee TH, Martin JN, Deeks SG, Tobler LH, Busch M, Hunt PW, Page K. A closer look at hepatitis C clearance in HIV controllers: a response. 2014. PMID: 25028914

  62. Santos GM, Wilson EC, Rapues J, Macias O, Packer T, Raymond HF. HIV treatment cascade among transgender women in a San Francisco respondent driven sampling study. 2014. PMID: 24714446

  63. Santos GM, Rapues J, Wilson EC, Macias O, Packer T, Colfax G, Raymond HF. Alcohol and substance use among transgender women in San Francisco: prevalence and association with human immunodeficiency virus infection. 2014. PMID: 24628655

  64. Santos GM, Coffin PO, Vittinghoff E, DeMicco E, Das M, Matheson T, Raiford JL, Carry M, Colfax G, Herbst JH, Dilley JW. Substance use and drinking outcomes in Personalized Cognitive Counseling randomized trial for episodic substance-using men who have sex with men. 2014. PMID: 24641808

  65. Pyun T, Santos GM, Arreola S, Do T, Hebert P, Beck J, Makofane K, Wilson PA, Ayala G. Internalized homophobia and reduced HIV testing among men who have sex with men in China. 2014. PMID: 24554493

  66. Santos GM, Do T, Beck J, Makofane K, Arreola S, Pyun T, Hebert P, Wilson PA, Ayala G. Syndemic conditions associated with increased HIV risk in a global sample of men who have sex with men. 2014. PMID: 24431183

  67. Asher AK, Santos GM, Evans J, Dokubo EK, Lee TH, Martin JN, Deeks SG, Tobler LH, Busch M, Hunt PW, Page K. Human leukocyte antigen B*57 does not fully explain hepatitis C clearance in HIV controllers. 2013. PMID: 23939233

  68. Santos GM, Emenyonu NI, Bajunirwe F, Rain Mocello A, Martin JN, Vittinghoff E, Bangsberg DR, Hahn JA. Self-reported alcohol abstinence associated with ART initiation among HIV-infected persons in rural Uganda. 2013. PMID: 24169501

  69. Santos GM, Beck J, Wilson PA, Hebert P, Makofane K, Pyun T, Do T, Arreola S, Ayala G. Homophobia as a barrier to HIV prevention service access for young men who have sex with men. 2013. PMID: 24135782

  70. Santos GM, Coffin PO, Das M, Matheson T, DeMicco E, Raiford JL, Vittinghoff E, Dilley JW, Colfax G, Herbst JH. Dose-response associations between number and frequency of substance use and high-risk sexual behaviors among HIV-negative substance-using men who have sex with men (SUMSM) in San Francisco. 2013. PMID: 23572012

  71. Coffin PO, Santos GM, Das M, Santos DM, Huffaker S, Matheson T, Gasper J, Vittinghoff E, Colfax GN. Aripiprazole for the treatment of methamphetamine dependence: a randomized, double-blind, placebo-controlled trial. 2013. PMID: 23186131

  72. Colfax GN, Santos GM, Das M, Santos DM, Matheson T, Gasper J, Shoptaw S, Vittinghoff E. Mirtazapine to reduce methamphetamine use: a randomized controlled trial. 2011. PMID: 22065532

  73. Colfax G, Santos GM, Chu P, Vittinghoff E, Pluddemann A, Kumar S, Hart C. Amphetamine-group substances and HIV. 2010. PMID: 20650520

  74. Das M, Chu PL, Santos GM, Scheer S, Vittinghoff E, McFarland W, Colfax GN. Decreases in community viral load are accompanied by reductions in new HIV infections in San Francisco. 2010. PMID: 20548786

  75. Das M, Santos D, Matheson T, Santos GM, Chu P, Vittinghoff E, Shoptaw S, Colfax GN. Feasibility and acceptability of a phase II randomized pharmacologic intervention for methamphetamine dependence in high-risk men who have sex with men. 2010. PMID: 20397286