Catherine Koss, MD

Associate Professor

Catherine Koss, MD is an Assistant Professor of Medicine in the Division of HIV, Infectious Diseases, and Global Medicine at San Francisco General Hospital. Dr. Koss conducts clinical research on HIV prevention and treatment, with a major focus on adherence measurement and strategies to optimize uptake of and adherence to pre-exposure prophylaxis (PrEP) among women in the United States and eastern Africa. She also has an interest in adherence to treatment and virologic outcomes among pregnant and postpartum women living with HIV. She is an attending physician on the HIV and Infectious Diseases consult service at San Francisco General Hospital and a clinical provider at the Ward 86 clinic.
Honors and Awards
  • Teri Liegler, PhD, Young Scientist Career Award, University of California, San Francisco, 2021
  • Population Health and Health Equity Scholar, University of California, San Francisco, 2020
  • IAS TB/HIV Research Prize, co-author, International AIDS Society, 2016
  • Early Career Award for Excellence in Clinical Research, UCSF Center for AIDS Research, 2016
  • Chief Fellow, Division of Infectious Diseases, University of California, San Francisco, 2013
  • John P. Phair Medical Student Award in infectious diseases, Northwestern University, 2009
  • Neil Stone Award for professionalism and compassion in medicine, Northwestern University, 2009
Websites
Publications

  1. Kabami J, Kabageni S, Koss CA, Okiring J, Nangendo J, Ruhamyankaka E, Ssebutinde P, Arinitwe E, Ayebare M, Napyo A, Mfitumukiza V, Tamu M, Kakande E, Katahoire AR, Musoke P, Kamya MR, Balzer LB, ENHANCED-SPS Study Team. A Peer-Mother Counseling Intervention Improves Early Infant HIV Testing in Rural Uganda. 2025. PMID: 40720828


  2. Kakande ER, Balzer LB, Kabami J, Ayieko J, Chamie G, Sutter N, Sunday H, Nyabuti M, Litunya J, Camlin C, Johnson-Peretz J, Temple J, Lavoy G, Koss C, Czarnogorski M, Petersen ML, Kamya MR, Havlir DV. Feasibility and acceptability of persons on long-acting cabotegravir for HIV prevention in the SEARCH Dynamic Choice HIV Prevention trial extension in rural Kenya and Uganda: a longitudinal cohort study. 2025. PMID: 40600471


  4. Ayieko J, Balzer LB, Aoko C, Sunday H, Kakande E, Kabami J, Koss C, Chamie G, Kamya MR, Petersen ML, Havlir DV. Uptake and patterns of PEP use within the context of a dynamic choice HIV prevention model in rural Uganda and Kenya: SEARCH Study. 2025. PMID: 40569865


  5. Jane Kabami, Laura B Balzer, Stella Kabageni, Catherine A Koss, Faith Kagoya, Jaffer Okiring, Joanita Nangendo, Emmanuel Ruhamyankaka, Peter Ssebutinde, Elizabeth Arinitwe, Michael Ayebare, John Bosco Tamu Munezeo, Valence Mfitumukiza, Anne R Katahoire, Moses R Kamya, Philippa Musoke. Peer-mother counseling improves HIV treatment adherence and status disclosure over time among pregnant and postpartum women in rural Uganda. 2025. PMID:


  6. Parikh UM, Gandhi M, Altamirano J, Safa H, Hazra A, Gomez LG, Shukla P, Hedberg T, Heaps AL, Halvas EK, Kuncze K, Okochi H, Walworth C, Conroy A, Bositis C, Chu C, Mellors JW, Koss CA. Early Virologic Success on Antiretroviral Therapy Among Individuals With Breakthrough HIV Acquisition on Long-Acting Cabotegravir Pre-exposure Prophylaxis. 2025. PMID: 40476034


  8. Kamya MR, Balzer LB, Ayieko J, Kabami J, Kakande E, Chamie G, Sutter N, Sunday H, Litunya J, Schwab J, Schrom J, Bacon M, Koss CA, Rinehart AR, Petersen M, Havlir DV, SEARCH Consortium. Dynamic choice HIV prevention with cabotegravir long-acting injectable in rural Uganda and Kenya: a randomised trial extension. 2024. PMID: 39395424


  9. Koss CA, Gandhi M, Halvas EK, Okochi H, Chu C, Glidden DV, Georgetti Gomez L, Heaps AL, Conroy AA, Tran M, Shetler C, Hoeth D, Kuncze K, Louie A, Rivera Garza H, Wafula Mugoma E, Penrose KJ, Chohan BH, Ayieko JO, Mills A, Patel RR, Mellors JW, Parikh UM. First Case of HIV Seroconversion With Integrase Resistance Mutations on Long-Acting Cabotegravir for Prevention in Routine Care. 2024. PMID: 39229286


  10. Gandhi M, Hill L, Grochowski J, Nelson A, Koss CA, Mayorga-Munoz F, Oskarsson J, Shiels M, Avery A, Bamford L, Baron J, Short WR, Hileman CO. Case Series of People With HIV on the Long-Acting Combination of Lenacapavir and Cabotegravir: Call for a Trial. 2024. PMID: 38628952


  11. Kabami J, Koss CA, Sunday H, Biira E, Nyabuti M, Balzer LB, Gupta S, Chamie G, Ayieko J, Kakande E, Bacon MC, Havlir D, Kamya MR, Petersen M, SEARCH Study Team. Randomized Trial of Dynamic Choice HIV Prevention at Antenatal and Postnatal Care Clinics in Rural Uganda and Kenya. 2024. PMID: 38489493


  12. Koss CA, Ayieko J, Kabami J, Balzer LB, Kakande E, Sunday H, Nyabuti M, Wafula E, Shade S, Biira E, Opel F, Atuhaire HN, Okochi H, Ogachi S, Gandhi M, Bacon MC, Bukusi EA, Chamie G, Petersen ML, Kamya MR, Havlir DV, SEARCH study team. Dynamic choice HIV prevention intervention at outpatient departments in rural Kenya and Uganda: a randomized trial. 2023. PMID: 37861683


  13. Kabami J, Kakande E, Chamie G, Balzer LB, Petersen ML, Camlin CS, Nyabuti M, Koss CA, Bukusi EA, Kamya MR, Havlir DV, Ayieko J. Uptake of a patient-centred dynamic choice model for HIV prevention in rural Kenya and Uganda: SEARCH SAPPHIRE study. 2023. PMID: 37408473


  14. Marquez C, Chen Y, Atukunda M, Chamie G, Balzer LB, Kironde J, Ssemmondo E, Mwangwa F, Kabami J, Owaraganise A, Kakande E, Abbott R, Ssekyanzi B, Koss C, Kamya MR, Charlebois ED, Havlir DV, Petersen ML. The Association Between Social Network Characteristics and Tuberculosis Infection Among Adults in Nine Rural Ugandan Communities. 2022. PMID: 35982635


  15. Camlin CS, Getahun M, Koss CA, Owino L, Akatukwasa C, Itiakorit H, Onyango A, Bakanoma R, Atwine F, Maeri I, Ayieko J, Atukunda M, Owaraganise A, Mwangwa F, Sang N, Kabami J, Kaplan RL, Chamie G, Petersen ML, Cohen CR, Bukusi EA, Kamya MR, Havlir DV, Charlebois ED. Providers' Attitudes and Experiences with Pre-Exposure Prophylaxis Implementation in a Population-Based Study in Kenya and Uganda. 2022. PMID: 36201226


  17. Phillips AN, Bershteyn A, Revill P, Bansi-Matharu L, Kripke K, Boily MC, Martin-Hughes R, Johnson LF, Mukandavire Z, Jamieson L, Meyer-Rath G, Hallett TB, Ten Brink D, Kelly SL, Nichols BE, Bendavid E, Mudimu E, Taramusi I, Smith J, Dalal S, Baggaley R, Crowley S, Terris-Prestholt F, Godfrey-Faussett P, Mukui I, Jahn A, Case KK, Havlir D, Petersen M, Kamya M, Koss CA, Balzer LB, Apollo T, Chidarikire T, Mellors JW, Parikh UM, Godfrey C, Cambiano V, HIV Modelling Consortium. Cost-effectiveness of easy-access, risk-informed oral pre-exposure prophylaxis in HIV epidemics in sub-Saharan Africa: a modelling study. 2022. PMID: 35489378


  18. Ayieko J, Petersen ML, Kabami J, Mwangwa F, Opel F, Nyabuti M, Charlebois ED, Peng J, Koss CA, Balzer LB, Chamie G, Bukusi EA, Kamya MR, Havlir DV. Uptake and outcomes of a novel community-based HIV post-exposure prophylaxis (PEP) programme in rural Kenya and Uganda. 2021. PMID: 34152067


  19. Okochi H, Louie A, Phung N, Zhang K, Tallerico RM, Kuncze K, Spinelli MA, Koss CA, Benet LZ, Gandhi M. Tenofovir and emtricitabine concentrations in hair are comparable between individuals on tenofovir disoproxil fumarate versus tenofovir alafenamide-based ART. 2021. PMID: 33742745


  20. Koss CA, Havlir DV, Ayieko J, Kwarisiima D, Kabami J, Chamie G, Atukunda M, Mwinike Y, Mwangwa F, Owaraganise A, Peng J, Olilo W, Snyman K, Awuonda B, Clark TD, Black D, Nugent J, Brown LB, Marquez C, Okochi H, Zhang K, Camlin CS, Jain V, Gandhi M, Cohen CR, Bukusi EA, Charlebois ED, Petersen ML, Kamya MR, Balzer LB. HIV incidence after pre-exposure prophylaxis initiation among women and men at elevated HIV risk: A population-based study in rural Kenya and Uganda. 2021. PMID: 33561143


  21. Mwangwa F, Getahun M, Itiakorit H, Jain V, Ayieko J, Owino L, Akatukwasa C, Maeri I, Koss CA, Chamie G, Clark TD, Kabami J, Atukunda M, Kwarisiima D, Sang N, Bukusi EA, Kamya MR, Petersen ML, Cohen CR, Charlebois ED, Havlir DV, Camlin CS. Provider and Patient Perspectives of Rapid ART Initiation and Streamlined HIV Care: Qualitative Insights From Eastern African Communities. 2021. PMID: 34841945


  22. Balzer LB, Havlir DV, Kamya MR, Chamie G, Charlebois ED, Clark TD, Koss CA, Kwarisiima D, Ayieko J, Sang N, Kabami J, Atukunda M, Jain V, Camlin CS, Cohen CR, Bukusi EA, van der Laan M, Petersen ML. Machine learning to identify persons at high-risk of HIV acquisition in rural Kenya and Uganda. 2019. PMID: 31697383


  23. Kabami J, Balzer LB, Saddiki H, Ayieko J, Kwarisiima D, Atukunda M, Charlebois ED, Clark TD, Koss CA, Ruel T, Bukusi EA, Cohen CR, Musoke P, Petersen ML, Havlir DV, Kamya MR, Chamie G. Population-level viral suppression among pregnant and postpartum women in a universal test and treat trial. 2020. PMID: 32472768


  24. Camlin CS, Koss CA, Getahun M, Owino L, Itiakorit H, Akatukwasa C, Maeri I, Bakanoma R, Onyango A, Atwine F, Ayieko J, Kabami J, Mwangwa F, Atukunda M, Owaraganise A, Kwarisiima D, Sang N, Bukusi EA, Kamya MR, Petersen ML, Cohen CR, Charlebois ED, Havlir DV. Understanding Demand for PrEP and Early Experiences of PrEP Use Among Young Adults in Rural Kenya and Uganda: A Qualitative Study. 2020. PMID: 31955361


  25. Budak JZ, Brickman CE, Abdoler EA, Wallender EK, Mulliken JS, Kerkhoff AD, Lampiris H, Babik JM, Koss CA, Schwartz BS. Response to: Is Burnout Infectious? Understanding Drivers of Burnout and Job Satisfaction Among Academic Infectious Diseases Physicians. 2020. PMID: 32284950


  26. Koss CA, Charlebois ED, Ayieko J, Kwarisiima D, Kabami J, Balzer LB, Atukunda M, Mwangwa F, Peng J, Mwinike Y, Owaraganise A, Chamie G, Jain V, Sang N, Olilo W, Brown LB, Marquez C, Zhang K, Ruel TD, Camlin CS, Rooney JF, Black D, Clark TD, Gandhi M, Cohen CR, Bukusi EA, Petersen ML, Kamya MR, Havlir DV. Uptake, engagement, and adherence to pre-exposure prophylaxis offered after population HIV testing in rural Kenya and Uganda: 72-week interim analysis of observational data from the SEARCH study. 2020. PMID: 32087152


  27. Lesosky M, Raboud JM, Glass T, Brummel SS, Ciaranello AL, Currier JS, Essajee S, Havlir DV, Koss CA, Ogwu A, Shapiro RL, Abrams EJ, Myer L. Comparison of guidelines for HIV viral load monitoring among pregnant and breastfeeding women in sub-Saharan Africa. 2020. PMID: 31634186


  28. Olilo WA, Petersen ML, Koss CA, Wafula E, Kwarisiima D, Kadede K, Clark TD, Cohen CR, Bukusi EA, Kamya MR, Charlebois ED, Havlir DV, Ayieko J, SEARCH Collaboration. Pre-exposure Prophylaxis (PrEP) Uptake Among Older Individuals in Rural Western Kenya. 2019. PMID: 31490343


  29. Jehan Budak, Cristina Brickman, Emily Abdoler, Erika Wallender, Jennifer S Mulliken, Andrew D Kerkhoff, Harry Lampiris, Jennifer M Babik, Catherine Koss, Brian Schwartz, Brian Schwartz. 2534. Development of an Infectious Diseases Fellowship Well-Being Program. 2019. PMID:


  30. Riley ED, Vittinghoff E, Koss CA, Christopoulos KA, Clemenzi-Allen A, Dilworth SE, Carrico AW. Housing First: Unsuppressed Viral Load Among Women Living with HIV in San Francisco. 2019. PMID: 31324996


  31. Havlir DV, Balzer LB, Charlebois ED, Clark TD, Kwarisiima D, Ayieko J, Kabami J, Sang N, Liegler T, Chamie G, Camlin CS, Jain V, Kadede K, Atukunda M, Ruel T, Shade SB, Ssemmondo E, Byonanebye DM, Mwangwa F, Owaraganise A, Olilo W, Black D, Snyman K, Burger R, Getahun M, Achando J, Awuonda B, Nakato H, Kironde J, Okiror S, Thirumurthy H, Koss C, Brown L, Marquez C, Schwab J, Lavoy G, Plenty A, Mugoma Wafula E, Omanya P, Chen YH, Rooney JF, Bacon M, van der Laan M, Cohen CR, Bukusi E, Kamya MR, Petersen M. HIV Testing and Treatment with the Use of a Community Health Approach in Rural Africa. 2019. PMID: 31314966


  32. Guimaraes AO, Cao Y, Hong K, Mayba O, Peck M, Gutierrez J, Ruffin F, Carrasco-Triguero M, Dinoso JB, Clemenzi-Allen A, Koss CA, Maskarinec S, Chambers HF, Fowler VG, Baruch A, Rosenberger CM. A prognostic model of persistent bacteremia and mortality in complicated S. aureus bloodstream infection. 2018. PMID: 30165412


  33. Mayer CM, Owaraganise A, Kabami J, Kwarisiima D, Koss CA, Charlebois ED, Kamya MR, Petersen ML, Havlir DV, Jewell BL. Distance to clinic is a barrier to PrEP uptake and visit attendance in a community in rural Uganda. 2019. PMID: 31037845


  34. Gutierrez J, Guimaraes AO, Lewin-Koh N, Berhanu A, Xu M, Cao Y, Kim J, Yan D, Chang JK, Dinoso JB, Koss CA, Clemenzi-Allen A, Chambers HF, Peck MC, Baruch A, Rosenberger CM. Sustained Circulating Bacterial Deoxyribonucleic Acid Is Associated With Complicated Staphylococcus aureus Bacteremia. 2019. PMID: 31024970


  35. Koss CA, Ayieko J, Mwangwa F, Owaraganise A, Kwarisiima D, Balzer LB, Plenty A, Sang N, Kabami J, Ruel TD, Black D, Camlin CS, Cohen CR, Bukusi EA, Clark TD, Charlebois ED, Petersen ML, Kamya MR, Havlir DV, SEARCH Collaboration. Early Adopters of Human Immunodeficiency Virus Preexposure Prophylaxis in a Population-based Combination Prevention Study in Rural Kenya and Uganda. 2018. PMID: 29741594


  36. Koss CA, Liu AY, Castillo-Mancilla J, Bacchetti P, McHugh C, Kuncze K, Morrow M, Louie A, Seifert S, Okochi H, MaWhinney S, Gandhi M, Anderson PL. Similar tenofovir hair concentrations in men and women after directly observed dosing of tenofovir disoproxil fumarate/emtricitabine: implications for preexposure prophylaxis adherence monitoring. 2018. PMID: 30212404


  37. Gandhi M, Bacchetti P, Rodrigues WC, Spinelli M, Koss CA, Drain PK, Baeten JM, Mugo NR, Ngure K, Benet LZ, Okochi H, Wang G, Vincent M. Development and Validation of an Immunoassay for Tenofovir in Urine as a Real-Time Metric of Antiretroviral Adherence. 2018. PMID: 30906930


  38. Johnny Gutierrez, Alessander Guimaraes, Melicent C. Peck, Aklile Barhanu, Min Xu, Yi Cao, Janice Kim, Donghong Yan, Joanna K. Chang, Jason Dinoso, Catherine Koss, Angelo Clemenzi-Allen, Henry F. Chambers, Carrie Rosenberger, Amos Baruch. Circulating bacterial DNA is associated with disease severity in patients with S. aureus bacteremia. 2018. PMID:


  39. McDonald CR, Conroy AL, Gamble JL, Papp E, Hawkes M, Olwoch P, Natureeba P, Kamya M, Silverman M, Cohan D, Koss CA, Dorsey G, Kain KC, Serghides L. Estradiol Levels Are Altered in Human Immunodeficiency Virus-Infected Pregnant Women Randomized to Efavirenz-Versus Lopinavir/Ritonavir-Based Antiretroviral Therapy. 2018. PMID: 29136115


  40. Koss CA, Hosek SG, Bacchetti P, Anderson PL, Liu AY, Horng H, Benet LZ, Kuncze K, Louie A, Saberi P, Wilson CM, Gandhi M. Comparison of Measures of Adherence to Human Immunodeficiency Virus Preexposure Prophylaxis Among Adolescent and Young Men Who Have Sex With Men in the United States. 2018. PMID: 29020194


  41. Roh ME, Shiboski S, Natureeba P, Kakuru A, Muhindo M, Ochieng T, Plenty A, Koss CA, Clark TD, Awori P, Nakalambe M, Cohan D, Jagannathan P, Gosling R, Havlir DV, Kamya MR, Dorsey G. Protective effect of indoor residual spraying of insecticide on preterm birth among pregnant women with HIV in Uganda: A secondary data analysis. Volume 216 of Issue 12. 2017. PMID: 29029337


  42. Pintye J, Bacchetti P, Teeraananchai S, Kerr S, Prasitsuebsai W, Singtoroj T, Kuncze K, Louie A, Koss CA, Jin C, Phung N, Horng H, Sohn AH, Gandhi M. Brief Report: Lopinavir Hair Concentrations Are the Strongest Predictor of Viremia in HIV-Infected Asian Children and Adolescents on Second-Line Antiretroviral Therapy. 2017. PMID: 28825944


  44. Gandhi M, Murnane PM, Bacchetti P, Elion R, Kolber MA, Cohen SE, Horng H, Louie A, Kuncze K, Koss CA, Anderson PL, Buchbinder S, Liu A. Hair levels of preexposure prophylaxis drugs measure adherence and are associated with renal decline among men/transwomen. 2017. PMID: 28832411


  45. Natureeba P, Kakuru A, Muhindo M, Ochieng T, Ategeka J, Koss CA, Plenty A, Charlebois ED, Clark TD, Nzarubara B, Nakalembe M, Cohan D, Rizzuto G, Muehlenbachs A, Ruel T, Jagannathan P, Havlir DV, Kamya MR, Dorsey G. Intermittent Preventive Treatment With Dihydroartemisinin-Piperaquine for the Prevention of Malaria Among HIV-Infected Pregnant Women. 2017. PMID: 28329368


  46. Kajubi R, Huang L, Jagannathan P, Chamankhah N, Were M, Ruel T, Koss CA, Kakuru A, Mwebaza N, Kamya M, Havlir D, Dorsey G, Rosenthal PJ, Aweeka FT. Antiretroviral Therapy With Efavirenz Accentuates Pregnancy-Associated Reduction of Dihydroartemisinin-Piperaquine Exposure During Malaria Chemoprevention. 2017. PMID: 28187497


  47. Koss CA, Bacchetti P, Hillier SL, Livant E, Horng H, Mgodi N, Mirembe BG, Gomez Feliciano K, Horn S, Liu AY, Glidden DV, Grant RM, Benet LZ, Louie A, van der Straten A, Chirenje ZM, Marrazzo JM, Gandhi M. Differences in Cumulative Exposure and Adherence to Tenofovir in the VOICE, iPrEx OLE, and PrEP Demo Studies as Determined via Hair Concentrations. 2017. PMID: 28253024


  48. Koss CA, Natureeba P, Kwarisiima D, Ogena M, Clark TD, Olwoch P, Cohan D, Okiring J, Charlebois ED, Kamya MR, Havlir DV. Viral Suppression and Retention in Care up to 5 Years After Initiation of Lifelong ART During Pregnancy (Option B+) in Rural Uganda. 2017. PMID: 27828878


  49. Gerona R, Wen A, Koss C, Bacchetti P, Gandhi M, Metcalfe J. A multi-analyte panel for non-invasive pharmacokinetic monitoring of second-line anti-tuberculosis drugs. 2016. PMID: 27287660


  51. Koss CA, Natureeba P, Nyafwono D, Plenty A, Mwesigwa J, Nzarubara B, Clark TD, Ruel TD, Achan J, Charlebois ED, Cohan D, Kamya MR, Havlir DV, Young SL. Brief Report: Food Insufficiency Is Associated With Lack of Sustained Viral Suppression Among HIV-Infected Pregnant and Breastfeeding Ugandan Women. 2016. PMID: 26397935


  52. Koss CA, Jarlsberg LG, den Boon S, Cattamanchi A, Davis JL, Worodria W, Ayakaka I, Sanyu I, Huang L. A Clinical Predictor Score for 30-Day Mortality among HIV-Infected Adults Hospitalized with Pneumonia in Uganda. 2015. PMID: 25962069


  53. Koss CA, Natureeba P, Mwesigwa J, Cohan D, Nzarubara B, Bacchetti P, Horng H, Clark TD, Plenty A, Ruel TD, Achan J, Charlebois ED, Kamya MR, Havlir DV, Gandhi M. Hair concentrations of antiretrovirals predict viral suppression in HIV-infected pregnant and breastfeeding Ugandan women. 2015. PMID: 25985404


  54. Cohan D, Natureeba P, Koss CA, Plenty A, Luwedde F, Mwesigwa J, Ades V, Charlebois ED, Gandhi M, Clark TD, Nzarubara B, Achan J, Ruel T, Kamya MR, Havlir DV. Efficacy and safety of lopinavir/ritonavir versus efavirenz-based antiretroviral therapy in HIV-infected pregnant Ugandan women. 2015. PMID: 25426808


  55. Koss CA, Natureeba P, Plenty A, Luwedde F, Mwesigwa J, Ades V, Charlebois ED, Clark TD, Achan J, Ruel T, Nzarubara B, Kamya MR, Havlir DV, Cohan D. Risk factors for preterm birth among HIV-infected pregnant Ugandan women randomized to lopinavir/ritonavir- or efavirenz-based antiretroviral therapy. 2014. PMID: 25072616


  56. Koss CA, Baras DC, Lane SD, Aubry R, Marcus M, Markowitz LE, Koumans EH. Investigation of metronidazole use during pregnancy and adverse birth outcomes. 2012. PMID: 22751543


  58. Huskamp HA, Donohue JM, Koss C, Berndt ER, Frank RG. Generic entry, reformulations and promotion of SSRIs in the US. 2008. PMID: 18563951