Trends in HIV Viral Suppression in the POP-UP Low-Barrier Care Program for People With HIV Experiencing Homelessness or Unstable Housing

Elizabeth Imbert; Lisa Fleming; Jon Oskarsson; Caycee Cullen; Mary Shiels; John Friend; Joi Jackson; Lindsay Felten; Negin Zahedikia; Francis Montgomery; Liria Santos; Francis Mayorga-Munoz; Yesenia Rodriguez; Yenifer Breganza; Janet Grochowski; Jennifer Cohen; Ayesha Appa; Kim Koester; Xavier Erguera; Edwin Charlebois; Monica Gandhi; Diane V Havlir; Katerina Christopoulos; Matthew D Hickey

doi:10.1093/ofid/ofag263

Trends in HIV Viral Suppression in the POP-UP Low-Barrier Care Program for People With HIV Experiencing Homelessness or Unstable Housing

Open Forum Infect Dis. 2026 Apr 30;13(5):ofag263. doi: 10.1093/ofid/ofag263. eCollection 2026 May.

Authors

Elizabeth Imbert¹, Lisa Fleming¹, Jon Oskarsson¹, Caycee Cullen¹, Mary Shiels¹, John Friend¹, Joi Jackson¹, Lindsay Felten¹, Negin Zahedikia¹, Francis Montgomery², Liria Santos¹, Francis Mayorga-Munoz¹, Yesenia Rodriguez¹, Yenifer Breganza¹, Janet Grochowski¹, Jennifer Cohen¹, Ayesha Appa¹, Kim Koester³, Xavier Erguera¹, Edwin Charlebois³, Monica Gandhi¹, Diane V Havlir¹, Katerina Christopoulos¹, Matthew D Hickey¹

Affiliations

¹ Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, SanFrancisco, San Francisco, California, USA.
² Alliance Health Project, University of California, SanFrancisco, San Francisco, California, USA.
³ Center for AIDS Prevention Studies, Department of Medicine, University of California, SanFrancisco, San Francisco, California, USA.

Abstract

Background: Human immunodeficiency virus (HIV) viral suppression remains suboptimal among people with HIV (PWH) facing barriers such as homelessness, substance use, and mental health disorders. In 2019, Ward 86 launched the POP-UP program, a low-barrier HIV care model serving PWH with unstable housing and difficulty engaging in care. In 2021, we introduced long-acting antiretroviral therapy (LA-ART), including for PWH unable to attain viral suppression on oral antiretroviral therapy. This study evaluates temporal trends in viral suppression and mortality rates within the POP-UP program.

Methods: We conducted a retrospective cohort study of PWH enrolled in the POP-UP program between August 2019 and December 2024. Eligibility included viremia (HIV viral load ≥200 copies/mL) or being off antiretroviral therapy, homelessness/unstable housing, and difficulty engaging in care. Criteria later expanded to include PWH with severe mental health or substance use disorders. The primary outcomes were viral suppression (<200 copies/mL) and death.

Results: Among 241 PWH ever enrolled in POP-UP, 86% attained viral suppression at least once during follow-up. Cross-sectional viral suppression was 47% in August 2019 (8 months after program inception) and increased to 64% in December 2024. By December 2024, 46% of suppressed patients were on LA-ART. The mortality rate declined from 8.8/100 person-years in 2020 to 2.6/100 person-years in 2024, with reductions in both AIDS-related and overdose deaths.

Conclusions: The POP-UP program improved viral suppression and may have reduced the mortality rate among PWH with substantial barriers to care. Improvements were likely driven by integration of LA-ART and continued quality improvement. Persistent viremia within the program highlights the need for additional strategies to address structural and psychosocial barriers.

Keywords: HIV; long-acting antiretroviral therapy; low-barrier care.