Susan Cassels

Susie Cassels
University of California, Santa Barbara
Professor and Director of the Broom Center

Susan Cassels’ work spans many disciplines, including demography, epidemiology, and geography. Her research interests are in the areas of population health, migration, epidemic modeling, HIV/AIDS, and sexual networks. Currently, her research is focused on migration and residential mobility and its effects on sexual risk behavior, sexual network structure and HIV transmission. She has ongoing projects among heterosexuals in Ghana and among men who have sex with men in Seattle, Washington. Cassels’ and her colleagues have published a number of mathematical models that examine unexpected consequences of HIV prevention interventions. Cassels’ research has been funded by the National Institutes of Health and the Bill & Melinda Gates Foundation.

Grants, Awards and Distinctions:

Making space for HIV prevention: substance use among Latinx MSM in LA hotspots
NIH/NIDA 3R21 DA049643-02S1. PI. 7/2021 – 6/2023 (NCE). $148,692

Exploring Social and Structural Determinants of HIV Risk Among Latinx Immigrant MSM UCSB Migration Initiative. Cassels, S. and Cerezo, A. (Multiple PI). $9,848

Activity spaces for HIV risk and prevention among diverse men who have sex with men in Los Angeles NIH/NIDA R21 DA049643. 7/2020 – 6/2022. $402,151. PI.

 A data-driven approach to modeling the effects of non-pharmaceutical interventions in disease progression dynamics at varying geographic granularities, UCSB VCR Seed Grant Collaborative Project. $50,297. Co-PI

The Migration & Prevention Cluster: Sexual Health among LGBTQ+ Communities, UCSB Chicano Studies Institute Research Cluster grant. $1,850. Multiple PI.

Center for AIDS Research. 2013-2018. NIH/NIAID P30 AI27757. Co-investigator; Role:  Core faculty in Sociobehavioral and Prevention Research Group

UCSB. 2016-2017. Spatial models of human migration, environment, and infectious disease transmission: The case of Zika virus disease Hellman Family Faculty Fellows Program, Cassels, S (PI), $20,000.

PIMSA Research Award. 2015-2016: Mexican migrant men who have sex with men, sexual networks, and prevention hotspots in San Bernardino County. Programa de Investigacion en Migration Y Salud Cassels, S. & Magis-Rodriguez, C. (Multiple PI), 2017 – 2019. $30,000.

Regents’ Junior Faculty Fellowship (Internal UCSB). 2015-2016. Immigration, residential mobility, and HIV risk among minority men who have sex with men. Cassels, S. (PI), Percent effort: 1 summer month, $7,500.

NIH/NICHD R21 HD080523. 2015-2017. Mathematical models to inform effective home-use HIV testing strategies for MSM. Cassels, S. (PI). $434,851.UW Center for AIDS Research (P30 AI27757)

New Investigator Award. 2013-2015. “HIV and residential mobility among men who have sex with men over the lifecourse” Principle Investigator. $108,805.

The Bill & Melinda Gates Foundation. 2013-2014. “Improving the Interoperability of Data and Models for Surveillance and Intervention Monitoring.” Co-investigator.


Reid S, Wang V, Assaf R, Kaloper S, Gorbach PM, Shoptaw S, Murray AT, Cassels S. 2023. 
"Implementation and Validation of Location-Based Survey to Assess Geographic Network and Hotspots of Sex and Drug Use in Los Angeles County. "
 JMIR Formative Research 7:e45188 (PMCID: PMC10337421)
Cassels, S., Cerezo, A., Reid, S. C., Rivera, D. B., Loustalot, C., & Meltzer, D. (2023)
"Geographic mobility and its impact on sexual health and ongoing HIV transmission among migrant latinx men who have sex with men."
Social Science & Medicine, 320, 115635. 
Reid, S. C., Wang, V., Assaf, R. D., Kaloper, S., Murray, A. T., Shoptaw, S., Gorbach, P., & Cassels, S. (2023)
"Novel Location-Based Survey Using Cognitive Interviews to Assess Geographic Networks and Hotspots of Sex and Drug Use: Implementation and Validation Study."
JMIR Formative Research, 7(1), e45188.
Cassels S, Mwenda KM, Biney AAE, Jenness SM. 2021. 
"Is it the timing? Short-term mobility and coital frequency in Agbogbloshie, Ghana. "
Archives of Sexual Behavior 50(2):589-600. (PMCID: PMC7889649)
Hamilton DT, Katz DA, Luo W, Stekler JD, Rosenberg ES, Sullivan PS, Goodreau SM, Cassels S. 2021. 
"Effective strategies to promote HIV self-testing for men who have sex with men: evidence from a mathematical model. "
Epidemics 37:100518.
Cassels S, Van Den Abbeele S. 2021.
"A call for epidemic modeling to examine historical and structural drivers of racial disparities in infectious disease. "
Social Science & Medicine 276:113833. (PMCID: PMC8168281)
Cassels S. 2020. 
"Time, population mobility, and HIV transmission. "
The Lancet HIV. ePub Jan 14: DOI:
Lee J, Cassels S. 2020. 
"Immigrant generational differences in social support and sexual risk behaviors among men who have sex with men in Seattle, Washington. "
AIDS Education and Prevention.
Cassels S, Meltzer D, Loustalot C, Ragsdale A, Shoptaw S, Gorbach PM. 2020.
"Geographic mobility, place attachment, and the changing geography of sex among African American and Latinx MSM who use substances in Los Angeles. "
Journal of Urban Health 97(5):609-622.
Cassels S, Jenness SM, Biney AAE. 2019. 
"Coital frequency and male concurrent partnerships during pregnancy and postpartum in Agbogbloshie, Ghana. "
AIDS and Behavior: 23(6): 1508-1517
Camlin C, Cassels S, Seeley J. 2018. 
"Editorial: Bringing population mobility into focus to achieve HIV prevention goals."
JIAS: Journal of the International AIDS Society 21(S4):e25136. (PMCID: PMC6053544) 
Cassels S, Camlin C, Seeley. 2018. 
"One Step Ahead: timing and sexual networks in population mobility and HIV prevention and care."
JIAS: Journal of the International AIDS Society 21(S4):e25140. (PMCID: PMC6053478) 
Luo W, Katz DA, Hamilton DT, McKenney J, Jenness SM, Goodreau SM, Stekler JD, Rosenberg ES, Sullivan PS, Cassels S. 2018. 
"Development of an agent-based model to investigate the impact of HIV self-testing programs on men who have sex with men in Atlanta and Seattle."
JMIR Public Health and Surveillance 4(2):e58. (PMCID: PMC6045793) 
Luo W, Gao P, Cassels S. 2018. 
"A large-scale location-based social network to understanding the impact of human geo-social interaction patterns on vaccination strategies in an urbanized area."
Computers, Environment and Urban Systems.
Tuholske, C., Tane, Z., López-Carr, D., Roberts, D., & Cassels, S. 2017.
"Thirty Years of Land Use/Cover Change in the Caribbean: Assessing the Relationship between Urbanization and Mangrove Loss in Roatán, Honduras"
Applied Geography, 88, 84-93.
Toren KG, Buskin SE, Dombrowski JC, Cassels S, Golden MR. 2016. 
"Time from HIV diagnosis to viral load suppression: 2007-2013."
Sexually Transmitted Diseases 43(1): 34-40. (PMCID: PMC4902572).
Cassels S, Camlin CS. 2016. 
"Geographical mobility and heterogeneity of the HIV epidemic."
Published online first July 8 2016. The Lancet HIV.
Roberts ST, Khanna A, Barnabas RV, Goodreau SM, Baeten JM, Celum C, Cassels S. 2016. 
"Estimating the impact of universal antiretroviral therapy for HIV serodiscordant couples through home HIV testing: Insights from mathematical models."
JIAS: Journal of the International AIDS Society 19:20864. (PMCID: PMC4865806).
Jenness SM, Goodreau SM, Morris M, Cassels S. 2016. 
"Effectiveness of Combination Packages for HIV-1 Prevention in Sub-Saharan Africa Depends on Partnership Network Structure: A Mathematical Modeling Study."
Sexually Transmitted Infections. Published Online First: 9 June 2016.
Huang CE, Cassels S, Winer RL. 2015. 
"Self-reported sex partner dates for use in measuring concurrent partnerships: Correspondence between two assessment methods."
Archives of Sexual Behavior44(4): 873-883. (PMCID: PMC4382421).
Jenness SM, Biney AAE, Ampofo WK, Dodoo FN, Cassels S. 2015.
"Minimal Coital Dilution in Accra, Ghana."
JAIDS: Journal of Acquired Immune Deficiency Syndromes 69(1): 85-91.  (PMCID: PMC4424052).
Khanna A, Roberts ST, Cassels S, Ying R, John-Stewart G, Goodreau SM, Baeten JM, Murnane P, Celum C, Barnabas RV. 2015.
"Estimating PMTCT's Impact on Heterosexual HIV Transmission: A Mathematical Modeling Analysis."
PLoS ONE 10(8): e0134271. (PMCID: PMC4532442).
Katz DA, Cassels S, Stekler JD. 2014. 
"Response to the modelling analysis by Katz et al on the impact of replacing clinic-based HIV tests with home testing among men who have sex with men in Seattle: Authors' reply."
Sexually Transmitted Diseases 41(5):320.
Pearson CR, Cassels S. 2014. 
"Place and sexual partnership transition among young American Indian and Alaska Native Women."
AIDS & Behavior. 18(8): 1443-1453. NIMHMS 544384.
Research Themes:
Katz DA, Cassels S, Stekler JD. 2014. 
"Replacing Clinic-based Tests with Home-use Tests May Increase HIV Prevalence among Seattle Men Who Have Sex with Men: Evidence from a Mathematical Model."
Sexually Transmitted Diseases 41(1): 2-9. (PMCID: PMC3955208)
Cassels S, Jenness SM, Biney AAE, Ampofo WK, Dodoo FN. Forthcoming. 
"Migration, sexual networks, and HIV in Agbogbloshie, Ghana."
Demographic Research. 
Cassels S and Katz DA. 2013. 
"Seroadaptation among men who have sex with men: emerging research themes."
Current HIV/AIDS Reports10(4): 305-313. (PMCID: PMC3946930).
Research Themes:
Cassels S, Jenness SM, Khanna A. 2013. 
"Conceptual Framework and Research Methods for Migration and HIV Transmission Dynamics."
AIDS & Behavior: Nov 21. NIMHMS 543091.
Cassels S, Manhart L, Jenness S, and Morris M. 2013. 
"Short-term mobility and increased partnership concurrency among men in Zimbabwe."
PLoS ONE8(6): e66342. (PMCID: PMC368871)