EpidemiologyPopulation Impact and Efficiency of Improvements to HIV PrEP Under Conditions of High ART Coverage Among San Francisco Men Who Have Sex With MenLe Guillou, Adrien MD, MPHa,b; Buchbinder, Susan MDc; Scott, Hyman MDc; Liu, Albert MD, MPHc; Havlir, Diane MDd; Scheer, Susan PhD, MPHc,e; Jenness, Samuel M. PhDa Author Information aDepartment of Epidemiology, Emory University, Atlanta, GA; bDepartment of Research and Public Health, Reims Teaching Hospitals, Robert Debré Hospital, Reims, France; cBridge HIV, San Francisco Department of Public Health, San Francisco, CA; dDepartment of Medicine, University of California San Francisco, San Francisco, CA; and eHIV Epidemiology Section, San Francisco Department of Public Health, San Francisco, CA. Correspondence to: Adrien Le Guillou, MD, MPH, Emory University, 1520 Clifton Road, Atlanta, GA 30323 (e-mail: [email protected]). Supported by National Institutes of Health grants R21 MH112449 and R01 AI138783. A.L. has received funding for investigator sponsored research grants from Gilead Sciences and Viiv Healthcare, and he has led studies in which Gilead Sciences has donated study drug. The remaining authors have no conflicts of interest to disclose. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.jaids.com). JAIDS Journal of Acquired Immune Deficiency Syndromes: December 1, 2021 - Volume 88 - Issue 4 - p 340-347 doi: 10.1097/QAI.0000000000002781 Buy SDC Metrics Abstract Background: Key components of Ending the HIV Epidemic (EHE) plan include increasing HIV antiretroviral therapy (ART) and HIV pre-exposure prophylaxis (PrEP) coverage. One complication to addressing this service delivery challenge is the wide heterogeneity of HIV burden and health care access across the United States. It is unclear how the effectiveness and efficiency of expanded PrEP will depend on different baseline ART coverage. Methods: We used a network-based model of HIV transmission for men who have sex with men (MSM) in San Francisco. Model scenarios increased varying levels of PrEP coverage relative under current empirical levels of baseline ART coverage and 2 counterfactual levels. We assessed the effectiveness of PrEP with the cumulative percentage of infections averted (PIA) over the next decade and efficiency with the number of additional person-years needed to treat (NNT) by PrEP required to avert one HIV infection. Results: In our projections, only the highest levels of combined PrEP and ART coverage achieved the EHE goals. Increasing PrEP coverage up to 75% showed that PrEP effectiveness was higher at higher baseline ART coverage. Indeed, the PIA was 61% in the lowest baseline ART coverage population and 75% in the highest. The efficiency declined with increasing ART (NNT range from 41 to 113). Conclusions: Improving both PrEP and ART coverage would have a synergistic impact on HIV prevention even in a high baseline coverage city such as San Francisco. Efforts should focus on narrowing the implementation gaps to achieve higher levels of PrEP retention and ART sustained viral suppression. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.