A low-threshold and multicomponent program for homeless or unstably housed people with HIV

San Francisco, USA

The Positive Health On-site Program for Unstably Housed Populations (POP-UP) provides a no-appointment, clinic-based, low-threshold model of HIV care. POP-UP includes primary care, housing assistance, case management and patient navigation. POP-UP looks to address barriers to HIV care for people who are homeless or unstably housed and ultimately improve their viral suppression. Of the 75 people enrolled in the program, all of whom were off antiretroviral treatment (ART) when enrolled, 79% restarted ART within 7 days and 91% returned for follow-up within 90 days. At 6 months, 55% of participants were virally supressed.

Program description

POP-UP was launched in January 2019 at an HIV clinic at the San Francisco General Hospital that serves publicly insured or underinsured patients. To be eligible for the program, patients had to meet the following criteria:

  • had an HIV viral load more than 200 copies/ml or were off ART;
  • were homeless or unstably housed; and
  • had missed at least one primary care appointment and had at least two drop-in visits over the prior 12 months.

Patients were identified through San Francisco Department of Public Health (SFDPH) surveillance data and electronic medical record review. Patients could also be referred through providers and a linkage-to care program at the SFDPH. POP-UP staff reviewed referral eligibility and contacted a SFDPH HIV linkage-to-care navigator to determine how to enrol patients in the POP-UP program.

Once enrolled in the POP-UP program, patients could access low-threshold, high-intensity services including drop-in, and same-day restart of ART. Patients could also receive substance use treatment, primary health services, on-site laboratory services and assistance with HIV medication adherence and distribution. Patients were provided with social services that included care coordination, case management, referrals to housing, assistance with accessing public insurance coverage, patient navigation and wellness checks. Patients were also offered financial incentives in the form of grocery store gift cards. They received $10 for visits with a provider or social worker or for having blood drawn for laboratory tests and $25 every four months for maintaining a viral load less than 200 copies/ml.

POP-UP services were provided by a variety of staff including physicians, a nurse practitioner with a specialization in HIV, nurses, a social worker, a pharmacist, a pharmacist technician and a linkage-to-care navigator. A psychiatrist was available to medical providers for phone consultation. Staff met weekly for a case conference to discuss patients.


An analysis was completed for patients who attended the program from January 2019 to February 2020. There were 192 patients referred to the program, of whom 152 were deemed eligible. Seventy-five of those patients enrolled in the program. Of those not enrolled (77), 67 had not been reached, eight preferred to stay with their primary care providers and two enrolled later. All of those enrolled were off ART and viremic (i.e., viral load greater than 200 copies/ml).

Of those enrolled in the program:

  • 100% had a substance use disorder (91% methamphetamine use; 15% opiate use)
  • 77% had a mental health diagnosis
  • 51% were homeless (at the time of enrolment)

Of the 75 patients enrolled in the study, 79% (59) restarted ART within seven days of enrolment, 68% (51) returned for a visit with POP-UP staff within one month and 91% (68) returned for follow-up within three months. At six months, 55% (41/75) of patients were virally supressed. Of those virally supressed at six months, eight went on to have a viral rebound over 200 copies/ml and 16 left the program for various reasons (e.g., died, transferred back to primary care providers). During the first six months of the program, the average incentive paid to each patient was $15.98.

What does this mean for service providers?

The POP-UP program demonstrates that a vulnerable population of homeless or unstably housed people with HIV can show positive outcomes in HIV viral load suppression in a low-threshold HIV care program. This program provided a variety of approaches to increase access and adherence to HIV treatment, such as patient navigation, intensive case management and financial incentives. There is evidence that these tactics have favourable outcomes in other programs.

The researchers recognized that affordable housing is an important strategy for ending the HIV epidemic, in addition to addressing the clinical needs of people with HIV and other factors (e.g., substance use) that patients may face.

Lastly, many of the patients referred to the program did not go on to be enrolled, which highlights the difficulty in reaching and maintaining contact with this patient population. Strategies to reach homeless or unstably housed people need to be explored in similar programs, as this continues to be a challenge for programs and limits outcomes.

Related resources

Harm Reduction Satellite Sites Program

Health Navigation

Project HOPE


Imbert E, Hickey MD, Clemenzi-Allen A et al. Evaluation of the POP-UP programme: a multicomponent model of care for people living with HIV with homelessness or unstable housing. AIDS. 2021;35:1241-1246.